“If we knew what it is we were doing, it would not be called research. Would it?” -Albert Einstein.

Published Research - 2024

Artificial Intelligent Agent Architecture and Clinical Decision-Making in the Healthcare Sector

Hospitals in distressed communities have higher emergency general surgery mortality

Hospitals with decreasing cost-to-charge ratios bill greater surgical charges for similar outcomes

For the Love of the Game: Calculating the Premium Associated with Academic Surgical Practice

Clinical Applications of Machine Learning

Lower Socioeconomic Status Predicts Greater Obstacles to Care: Using Outpatient Cholecystectomy as a Model Cohort

Meta-Analysis in Surgical Research: Methodology and Statistical Application

Statewide Hospital Admissions for Adult Survivors of Infant Surgical Diseases Over a 10-Year Period

Expanded analysis for patients with acute cholecystitis indicates outcomes vary based on COVID-19 status and treatment modality

Prolonged Ileus Due to Underlying Shigella Infection After Bilateral Open Inguinal Hernia Repair

The continued financial effect of COVID: Increasing costs for non-elective major lower extremity amputations

Cirrhosis Increases the Rate of Failure of Nonoperative Management in Blunt Liver Injuries

Utility of mean nocturnal baseline impedance and post-reflux swallow-induced peristaltic wave index in clinical pH-impedance reflux study

Transition to Permitless Open Carry and Association with Firearm-Related Suicide

Examining surgeon stress in robotic and laparoscopic surgery

Survival Tree Provides Individualized Estimates of Survival After Lung Transplant

Huang KA, Choudhary HK, Kuo PC.

This paper examines the decision-making processes of physicians and intelligent agents within the healthcare sector, particularly focusing on their characteristics, architectures, and approaches. We provide a theoretical insight into the evolving role of artificial intelligence (AI) in healthcare, emphasizing its potential to address various healthcare challenges. Defining features of intelligent agents are explored, including their perceptual abilities and behavioral properties, alongside their architectural frameworks, ranging from reflex-based to general learning agents, and contrasted with the rational decision-making structure employed by physicians. Through data collection, hypothesis generation, testing, and reflection, physicians exhibit a nuanced approach informed by adaptability and contextual understanding. A comparative analysis between intelligent agents and physicians reveals both similarities and disparities, particularly in adaptability and contextual comprehension. While intelligent agents offer promise in enhancing clinical decisions, challenges with types of dataset biases pose significant hurdles. Informing and educating physicians about AI concepts can build trust and transparency in intelligent programs. Such efforts aim to leverage the strengths of both human and AI toward improving healthcare delivery and outcomes.

Keywords: ai; cognition; intelligent agents; physician decision-making; physician metacognition. Read More

Kendall MA, Zander T, Torikashvili J, Kuo PC, Grimsley EA

Emergency general surgery (EGS) is not only an independent risk factor for developing a major complication but also death, accounting for 50 ​% of operative mortality in the United States.1,2 Social determinants of health (SDOH) also impact operative outcomes, specifically mortality.3 One metric for SDOH is the Distressed Communities Index (DCI) which scores United States zip codes based on socioeconomic factors and categorizes them into quintiles: 1) prosperous, 2) comfortable, 3) mid-tier, 4) at-risk, and 5) distressed.4

Studies have largely focused on how patients’ SDOH impacts surgical outcomes. However, hospital socioeconomic factors may play a role in EGS patient outcomes and have yet to be studied. We hypothesize that EGS patients treated at distressed area hospitals (DAH) will have inferior outcomes to those treated at prosperous area hospitals (PAH).

Florida Agency for Healthcare Administration inpatient dataset (2018–2021) was queried for adult patients undergoing EGS within 24 hours of admission and stratified into low- (appendectomy, cholecystectomy, inguinal hernia repair) and high-risk procedures (small bowel resection, colon resection, lysis of adhesions, gastric excision/repair). Definition of high-risk was based on calculated risk of mortality >1 ​% and/or morbidity >15 ​%.5 DCI was linked to hospital zip code. Centers for Medicare and Medicaid Services (CMS) database linked hospital demographics to hospital Medicare number.

Univariable analysis compared patient demographics, hospital demographics, and outcomes (inpatient mortality and length of stay [LOS]) between hospital DCI quintiles. Propensity score matching (PSM) using k-nearest neighbors analysis method with a 1:1 ratio controlled for age, sex, race, ethnicity, comorbid conditions, acute conditions present on admission, high-risk vs. low-risk procedure type, and modality to compare PAH to DAH. To control for patient DCI, we performed adjusted subgroup analysis based on patient DCI and compared outcomes of PAH vs DAH. Multivariable logistic regression evaluated specific factors associated with inpatient mortality and non-home discharge, reported as odds ratio (OR) with 95 ​% confidence interval (CI). Subgroup analysis of DAH identified hospital factors associated with inpatient mortality and discharge status.

Overall, our results shed light on hospital SDOH and their association with inferior EGS outcomes. Healthcare policy development should target hospital DCI to allocate funding and resources towards stand-alone emergency departments and emergency medical services access. Read More

Zander T, Kendall MA, Janjua HM, Kuo PC, Grimsley EA.

Background: The cost-to-charge ratio reflects the markup of hospital services. A lower cost-to-charge ratio indicates lower costs and/or greater charges. This study examines factors associated with cost-to-charge ratio trends to determine whether decreasing cost-to-charge ratio is associated with worse surgical outcomes.

Methods: The Florida Agency for Healthcare Administration Inpatient database (2018-2020) was queried for common surgical procedures and linked to the Distressed Communities Index, RAND Corporation Hospital data, Center for Medicare Services Cost Reports, and American Hospital Association data. Only hospitals with monotonically increasing or decreasing cost-to-charge ratio were included in the study. Univariable analysis compared these hospitals. Using patient-level data, interpretable machine learning predicted cost-to-charge ratio trend while identifying influential factors.

Results: The cohort had 67 hospitals (27 increasing cost-to-charge ratio and 40 decreasing cost-to-charge ratio) with 35,661 surgeries. Decreasing cost-to-charge ratio hospitals were more often proprietarily owned (78% vs 33%, P = .01) and had greater mean total charges ($134,349 ± $114,510 vs $77,185 ± $82,027, P < .01) with marginally greater mean estimated costs ($14,863 ± $12,343 vs $14,458 ± $15,440, P < .01). Patients from decreasing cost-to-charge ratio hospitals had greater rates of most comorbidities (P < .05) but no difference in mortality or overall complications. Machine-learning models revealed charges rather than clinical factors as most influential in cost-to-charge ratio trend prediction.

Conclusions: Decreasing cost-to-charge ratio hospitals charge vastly more despite minimally greater estimated costs and no difference in outcomes. Although differences in case-mix existed, charges were the predominant differentiators. Patient clinical factors had far less of an impact. Read More

Grimsley EA, Anderson DO, Kendall MA, Zander T, Parikh R, Weigel RJ, Kuo PC.

Objective: We sought to determine the premium associated with a career in academic surgery, as measured by compensation normalized to the work relative value unit (wRVU).

Background: An academic surgical career, embodying innovation and mentorship, offers intrinsic rewards, but is not well monetized. We know compensation for academic surgeons is less than their non-academic counterparts, but the value of clinical effort, as normalized to the wRVU, between academic and non-academic surgeons has not been well characterized. Thus, we analyzed the variations in the valuation of academic and non-academic surgical work from 2010 to 2022.

Methods: We utilized Medical Group Management Association Provider Compensation data from 2010, 2014, 2018, and 2022 to compare academic and non-academic surgeons. We analyzed raw total cash compensation (TCC), wRVU, TCC per wRVU (TCC/wRVU), and TCC to collections (TCCtColl). We calculated collections per wRVU (Coll/wRVU). We adjusted TCC and TCCtColl for inflation using the Consumer Price Index. Linear modeling for trend analysis was performed.

Results: Compared to non-academic, academic surgeons had lower TCC (2010: $500,415.0±23,666 vs. $631,515.5±23,948.2, -21%; 2022: $564,789.8±23,993.9 vs. $628,247.4±15,753.2, -10%), despite higher wRVUs (2022: 9,109.4±474.9 vs. 8,062.7±252.7) and higher Coll/wRVU (2022: 76.68±8.15 vs. 71.80±6.10). Trend analysis indicated TCC will converge in 2038 at an estimated $660,931.

Conclusions: In 2022, academic surgeons had more clinical activity and superior organizational revenue capture, despite less total and normalized clinical compensation. Based on TCC/wRVUs, academia charges a premium of 16% over non-academic surgery. However, trend analysis suggests that TCC will converge within the next twenty years.

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Mateussi N, Rogers MP, Grimsley EA, Read M, Parikh R, Pietrobon R, Kuo PC.

Objective: This review introduces interpretable predictive machine learning approaches, natural language processing, image recognition, and reinforcement learning methodologies to familiarize end users.

Background: As machine learning, artificial intelligence, and generative artificial intelligence become increasingly utilized in clinical medicine, it is imperative that end users understand the underlying methodologies.

Methods: This review describes publicly available datasets that can be used with interpretable predictive approaches, natural language processing, image recognition, and reinforcement learning models, outlines result interpretation, and provides references for in-depth information about each analytical framework.

Results: This review introduces interpretable predictive machine learning models, natural language processing, image recognition, and reinforcement learning methodologies.

Conclusions: Interpretable predictive machine learning models, natural language processing, image recognition, and reinforcement learning are core machine learning methodologies that underlie many of the artificial intelligence methodologies that will drive the future of clinical medicine and surgery. End users must be well versed in the strengths and weaknesses of these tools as they are applied to patient care now and in the future.

Keywords: image recognition; interpretable predictive machine learning; machine learning; natural language processing; reinforcement learning. Read More

McGee MY, Janjua HM, Read MD, Kuo PC, Grimsley EA.

Background: Patients with low socioeconomic status (SES) are disadvantaged in terms of access to health care. A novel metric for SES is the Distressed Communities Index (DCI). This study evaluates the effect of DCI on hospital choice and distance traveled for surgery.

Methods: A Florida database was queried for patients with symptomatic cholelithiasis or chronic cholecystitis who underwent an outpatient cholecystectomy between 2016 and 2019. Patients' DCI was compared with hospital ratings, comorbidities, Charlson Comorbidity Index, and distance traveled for surgery. Stepwise logistic regression was used to determine which factors most influenced distance traveled for surgery.

Results: There were 54,649 cases-81 open, 52,488 laparoscopic, and 2,080 robotic. There was no difference between surgical approach and patient's DCI group (p = 0.12). Rural patients traveled the farthest for surgery (avg 21.29 miles); urban patients traveled the least (avg 5.84 miles). Patients from distressed areas more often had surgery at one- or two-star hospitals than prosperous patients (61% vs 36.3%). Regression indicated distressed or at-risk areas predicted further travel for rural/small-town patients, while higher hospital ratings predicted further travel for suburban/urban patients.

Discussion: Compared to prosperous areas, patients from distressed areas have surgery at lower-rated hospitals, travel further if they live in rural/small-town areas, but travel less if they live in suburban areas. We postulate that farther travel in rural areas may be explained by a lack of health care resources in poor, rural areas, while traveling less in suburban areas may be explained by personal lack of resources for patients with low SES.

Keywords: biliary; gastrointestinal; hepatobiliary; socioeconomic. Read More

Choi JH, Grimsley EA, Read MD, Rogers MP, Bulard B, Kuo PC.

Abstract

In evidence-based medicine, systematic review continues to carry the highest weight in terms of quality and reliability, synthesizing robust information from previously published cohort studies to provide a comprehensive overview of a topic. Meta-analysis provides further depth by allowing for comparative analysis between the studied intervention and the control group, providing the most up-to-date evidence on their characteristics and efficacy. We discuss the principles and methodology of meta-analysis, and its applicability to the field of surgical research. The clinical question is defined using PICO framework (Problem, Intervention, Comparison, Outcome). Then a systematic article search is performed across multiple medical databases using relevant search terms, which are then filtered out based on appropriate screening tools. Pertinent data from the selected articles are collected and undergo critical appraisal by at least two independent reviewers. Additional statistical tests may be performed to identify the presence of any significant bias. The data are then synthesized to perform comparative analysis between the intervention and comparison groups. In this article, we discuss specifically the usage of R software (R Foundation for Statistical Computing, Vienna, Austria) for data analysis and visualization. Meta-analysis results of the pooled data are presented using forest plots. Concerns for potential bias may be addressed through the creation of funnel plots. Meta-analysis is a powerful tool to provide highly reliable medical evidence. It may be readily performed by independent researchers with minimal need for funding or institutional approval. The ability to conduct such studies is an asset to budding medical scholars.

Keywords: general surgery; other; special topics. Read More

Rogers MP, Janjua H, Kuo PC, Chang HL.

Introduction: The number of patients with congenital disease living to adulthood continues to grow. Often undergoing surgical correction in infancy, they continue to require lifelong care. Their numbers are largely unknown. We sought to evaluate hospital admissions of adult patients with esophageal atresia with tracheoesophageal fistula (EA/TEF), congenital diaphragmatic hernia (CDH), and Hirschsprung disease (HD).

Methods: The Florida Agency for Healthcare Administration inpatient database was merged with the Distressed Communities Index and Centers for Medicare and Medicaid Services Hospital and Physician Compare datasets. The dataset was queried for adult patients (≥18 y, born after 1970) with EA/TEF, CDH, and HD in their problem list from 2010 to 2020. Patient demographics, hospitalization characteristics, and discharge information were obtained.

Results: In total, 1140 admissions were identified (266 EA/TEF, 135 CDH, 739 HD). Patients were mostly female (53%), had a mean age of 31.6 y, and often admitted to an adult internist in a general hospital under emergency. Principal diagnoses and procedures (when performed) varied with diagnosis and age at admission. EA patients were admitted with dysphagia and foregut symptoms and often underwent upper endoscopy with dilation. CDH patients were often admitted for diaphragmatic hernias and underwent adult diaphragm repair. Hirschsprung patients were often admitted for intestinal obstructive issues and frequently underwent colonoscopy but trended toward operative intervention with increasing age.

Conclusions: Adults with congenital disease continue to require hospital admission and invasive procedures. As age increases, diagnoses and performed procedures for each diagnoses evolve. These data could guide the formulation of multispecialty disease-specific follow-up programs for these patients.

Keywords: Adult congenital disease; Congenital diaphragmatic hernia; Esophageal atresia; Hirschsprung disease; Tracheoesophageal fistula. Read More

Grimsley EA, Torikashvili JV, Janjua HM, Pietrobon R, Zander T, Kendall MA, Kuo PC, Read MD; N3C Consortium.

Background: The impact of different phases of COVID-19 infection on outcomes from acute calculous cholecystitis (ACC) is not well understood. Therefore, we examined outcomes of acute cholecystitis during the COVID-19 pandemic, comparing the effect of different treatment modalities and COVID-19 infection status. We hypothesized that patients with acute COVID-19 would have worse outcomes than COVID-negative patients, but there would be no difference between COVID-negative and COVID-recovered patients.

Methods: We used 2020-2023 National COVID Cohort Collaborative data to identify adults with ACC. Treatment (antibiotics-only, cholecystostomy tube, or cholecystectomy) and COVID-19 status (negative, active, or recovered) were collected. Treatment failure of nonoperative managements was noted. Adjusted analysis using a series of generalized linear models controlled for confounders (age, sex, body mass index, Charlson comorbidity index, severity at presentation, and year) to better assess differences in outcomes among treatment groups, as well as between COVID-19 groups.

Results: In total, 32,433 patients (skewed count) were included: 29,749 COVID-negative, 2112 COVID-active, and 572 (skewed count) COVID-recovered. COVID-active had higher rates of sepsis at presentation. COVID-negative more often underwent cholecystectomy. Unadjusted, COVID-active had higher 30-day mortality, 30-day complication, and longer length of stay than COVID-negative and COVID-recovered. Adjusted analysis revealed cholecystectomy carried lower odds of mortality for COVID-active and COVID-negative patients than antibiotics or cholecystostomy. COVID-recovered patients' mortality was unaffected by treatment modality. Treatment failure from antibiotics was more common for COVID-negative patients.

Conclusion: Acute cholecystitis outcomes are affected by phase of COVID-19 infection and treatment modality. Cholecystectomy does not lead to worse outcomes for COVID-active and COVID-recovered patients than nonoperative treatments; thus, these patients can be considered for cholecystectomy if their physiology is not prohibitive.

Keywords: Acute cholecystitis; COVID-19; COVID-19 pandemic. Read More

Dalby C, Lippincott M, Olafson J, Kuo PC.

Abstract

We present a rare case of prolonged ileus caused by underlying Shigella infection after surgical hernia repair. Infectious disease is an uncommon cause of postoperative prolonged ileus in adults. Our 48-year-old male patient underwent bilateral open inguinal hernia repair and open umbilical hernia repair without complication at an academic institution, with same-day discharge. Eight days later, he presented to the emergency department with complaints of severe cramping abdominal pain, nausea, emesis, and watery diarrhea. Physical examination, computed tomography scan of the abdomen and pelvis, and abdominal X-ray were initially concerning for bowel obstruction. The patient was admitted to the general surgery service. Concern for ileus with underlying gastritis arose after a small bowel follow-through showed contrast eventually reaching the rectum. A subsequent gastrointestinal pathogens panel was positive for Shigella. The patient's symptoms resolved after appropriate antibiotic treatment. Shigellosis and other infectious diseases should be considered in the differential diagnosis of postoperative prolonged ileus.

Keywords: general surgery complication; ileus; infectious disease; inguinal hernia repair; shigella; umbilical hernia repair. Read More

Torikashvili JV, Read MD, Janjua HM, Parikh R, Kuo PC, Grimsley EA.

Background: The COVID-19 pandemic necessitated changes in processes of care, which significantly impacted surgical care. This study evaluated the impact of these changes on patient outcomes and costs for non-elective major lower extremity amputations (LEA).

Methods: The 2019-2021 Florida Agency for Health Care Administration database was queried for adult patients who underwent non-elective major LEA. Per-patient inflation-adjusted costs were collected. Patient cohorts were established based on Florida COVID-19 mortality rates: COVID-heavy (CH) included nine months with the highest mortality, COVID-light (CL) included nine months with the lowest mortality, and pre-COVID (PC) included nine months before COVID (2019). Outcomes included in-hospital patient outcomes and hospitalization cost.

Results: 6132 patients were included (1957 PC, 2104 CH, and 2071 CL). Compared to PC, there was increased patient acuity at presentation, but morbidity (31%), mortality (4%), and length of stay (median 12 [8-17] days) were unchanged during CH and CL. Additionally, costs significantly increased during the pandemic; median total cost rose 9%, room costs increased by 16%, ICU costs rose by 15%, and operating room costs rose by 15%. When COVID-positive patients were excluded, cost of care was still significantly higher during CH and CL.

Conclusions: Despite maintaining pre-pandemic standards, as evidenced by unchanged outcomes, the pandemic led to increased costs for patients undergoing non-elective major LEA. This was likely due to increased patient acuity, resource strain, and supply chain shortages during the pandemic.

Key message: While patient outcomes for non-elective major lower extremity amputations remained consistent during the COVID-19 pandemic, healthcare costs significantly increased, likely due to increased patient acuity and heightened pressures on resources and supply chains. These findings underscore the need for informed policy changes to mitigate the financial impact on patients and healthcare systems for future public health emergencies.

Keywords: COVID-19; Chronic limb ischemia; Lower extremity amputation; Pandemic; Vascular surgery. Read More

Grimsley EA, Lippincott M, Read MD, Lorch S, Farach SM, Kuo PC, Diaz JJ.

Abstract

Pre-existing cirrhosis is associated with increased mortality in blunt liver injury. Despite widespread use of nonoperative management (NOM) for blunt liver injury, there is a relative paucity of data regarding how pre-existing cirrhosis impacts the success of NOM. Herein, we perform a retrospective cohort study using ACS TQIP 2017-2020 data to assess the relationship between cirrhosis and failure of NOM for adult patients with blunt liver injury. 37,176 patients were included (342 cirrhosis and 36,834 without cirrhosis). After propensity-score matching, patients with pre-existing cirrhosis had higher rates of failure of NOM (32.2 vs 14.1%, p < 0.01) and in-hospital mortality (36.3 vs 10.8%, p < 0.01) than patients without cirrhosis. Hesitancy to operate on patients with pre-existing cirrhosis and trauma, as well as significant underlying coagulopathy, may explain these findings.

Keywords: blunt liver injury; cirrhosis; hepatobiliary; liver; trauma. Read More

Angelica B, Tippett M, Lim A, Wong S, Kuo P.

Background and aims: Analysis of mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave index (PSPWi) have been proposed to increase the diagnostic yield of pH-impedance studies in reflux disease. However, routine use of these indices in clinical studies is yet to be established, particularly with PSPWi, which requires laborious manual analysis. Our study aimed to assess the utility of MNBI and PSPWi and their potential for future incorporation into clinical practice.

Methods: pH-impedance recordings from consecutive patients referred to the Motility Laboratory at Royal Adelaide Hospital for evaluation of gastro-oesophageal reflux disease (GORD) were prospectively collected and manually analysed. Baseline demographic characteristics, symptoms, acid exposure time (AET), number of reflux episodes, and MNBI and PSPWi were collected.

Results: Eighty-nine patients were included in the study (age 50 ± 17 years, 35 males). MNBI and PSPWi inversely correlated with AET (R = -0.678, P < 0.0001 and R = -0.460, P < 0.0001 respectively) and with reflux episodes (R = -0.391, P = 0.0002 and R = -0.305, P = 0.0037 respectively). In patients with a negative pH study, but with typical reflux symptoms, 4/30 (13%) had pathologic MNBI and PSPWi. There was a positive correlation between MNBI and PSPWi values (R = 0.525, P < 0.0001). Performing analysis of PSPWi was substantially more laborious than MNBI.

Conclusion: MNBI and PSPWi are both useful adjuncts in the diagnosis of reflux disease, although in our cohort MNBI showed stronger correlation with AET with less time to analyse. The role of these indices remains to be further explored, particularly in patients with inconclusive AET and in those with positive compared to negative symptom association.

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Grimsley EA, Torikashvili JV, Janjua HM, Read MD, Kuo PC, Diaz JJ.

Background: Firearm-related death rates continue to rise in the US. As some states enact more permissive firearm laws, we sought to assess the relationship between a change to permitless open carry (PLOC) and subsequent firearm-related death rates, a currently understudied topic.

Study design: Using state-level data from 2013 to 2021, we performed a linear panel analysis using a state fixed-effects model. We examined total firearm-related death, suicide, and homicide rates separately. If a significant association between OC law and death rate was found, we then performed a difference-in-difference (DID) analysis to assess for a causal relationship between changing to PLOC and increased death rate. For significant DID results, we performed confirmatory DID separating firearm and nonfirearm death rates.

Results: Nineteen states maintained a no OC or permit-required law, whereas 5 changed to permitless and 26 had a PLOC before 2013. The fixed-effects model indicated more permissive OC law that was associated with increased total firearm-related deaths and suicides. In DID, changing law to PLOC had a significant average treatment effect on the treated of 1.57 (95% CI 1.05 to 2.09) for total suicide rate but no significant average treatment effect for the total firearm-related death rate. Confirmatory DID results found a significant average treatment effect on the treated of 1.18 (95% CI 0.90 to 1.46) for firearm suicide rate.

Conclusions: OC law is associated with total firearm-related death and suicide rates. Based on our DID results, changing to PLOC is indeed strongly associated with increased suicides by firearm. Read More

Sujka J, Ahmed A, Kang R, Grimsley EA, Weche M, Janjua H, Mi Z, English D, Martinez C, Velanovich V, Bennett RD, Docimo S, Saad AR, DuCoin C, Kuo PC.

Abstract

Robotic surgery may decrease surgeon stress compared to laparoscopic. To evaluate intraoperative surgeon stress, we measured salivary alpha-amylase and cortisol. We hypothesized robotic elicited lower increases in surgeon salivary amylase and cortisol than laparoscopic. Surgical faculty (n = 7) performing laparoscopic and robotic operations participated. Demographics: age, years in practice, time using laparoscopic vs robotic, comfort level and enthusiasm for each. Operative data included operative time, WRVU (surgical "effort"), resident year. Saliva was collected using passive drool collection system at beginning, middle and end of each case; amylase and cortisol measured using ELISA. Standard values were created using 7-minute exercise (HIIT), collecting saliva pre- and post-workout. Linear regression and Student's t test used for statistical analysis; p values < 0.05 were significant. Ninety-four cases (56 robotic, 38 laparoscopic) were collected (April-October 2022). Standardized change in amylase was 8.4 ± 4.5 (p < 0.001). Among operations, raw maximum amylase change in laparoscopic and robotic was 23.4 ± 11.5 and 22.2 ± 13.4; raw maximum cortisol change was 44.21 ± 46.57 and 53.21 ± 50.36, respectively. Values normalized to individual surgeon HIIT response, WRVU, and operative time, showing 40% decrease in amylase in robotic: 0.095 ± 0.12, vs laparoscopic: 0.164 ± 0.16 (p < 0.02). Normalized change in cortisol was: laparoscopic 0.30 ± 0.44, robotic 0.22 ± 0.4 (p = NS). On linear regression (p < 0.001), surgeons comfortable with complex laparoscopic cases had lower change in normalized amylase (p < 0.01); comfort with complex robotic was not significant. Robotic may be less physiologically stressful, eliciting less increase in salivary amylase than laparoscopic. Comfort with complex laparoscopic decreased stress in robotic, suggesting laparoscopic experience is valuable prior to robotic.

Keywords: Laparoscopic; Robotic; Salivary amylase; Salivary cortisol; Stress.

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Amika Moro, Haroon M. Janjua, Michael P Rogers, Madan G. Kundu, Ricardo Pietrobon, Meagan D. Read, Melissa Kendall, Tyler Zander, Paul C. Kuo, Emily A. Grimsley

Introduction: Identifying contributors to lung transplant survival is vital in mitigating mortality. To enhance individualized mortality estimation and determine variable interaction, we employed a survival tree algorithm utilizing recipient and donor data.                                                                                                                                                                                                               

Methods: United Network Organ Sharing data (2000-2021) was queried for single and double lung transplants in adult patients. Graft survival time <7 days was excluded. Sixty preoperative and immediate postoperative factors were evaluated with stepwise logistic regression on mortality; final model variables were included in survival tree modeling. Data were split into training and testing sets, and additionally validated with ten-fold cross validation. Survival tree pruning and model selection was based on Akaike information criteria and log-likelihood values. Estimated survival probabilities and log-rank pairwise comparisons between subgroups were calculated.

Results: A total of 27,296 lung transplant patients (8,175 single; 19,121 double) were included. Stepwise logistic regression yielded 47 significant variables associated with mortality. Survival tree modeling returned six significant factors: recipient age, length of stay from transplant to discharge, recipient ventilator duration post-transplant, double lung transplant, recipient reintubation post-transplant, and donor cytomegalovirus status. Eight subgroups consisting of combinations of these factors were identified with distinct Kaplan-Meier survival curves. Conclusions: Survival trees provide the ability to understand the effects and interactions of covariates on survival after lung transplantation. Individualized survival probability with this technique found that pre- and post-operative factors influence survival after lung transplantation. Thus, pre-operative patient counseling should acknowledge a degree of uncertainty given the influence of post-operative factors. Keywords: machine learning, lung transplant, survival tree analysis

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Recipient Survival Using Heart Transplant Survival Trees (RESILIENT): A Machine Learning Algorithm for Individualized Mortality Prediction

Michael P. Rogers, Haroon M. Janjua, Meagan Read, Madan G. Kundu, Ricardo Pietrobon, Paul C. Kuo

Purpose: Identifying factors affecting heart transplant survival is crucial in improving post-transplant outcomes. In effort to augment patient-specific mortality probability estimation and elucidate covariate interaction, we employed a survival tree modeling approach to the UNOS transplant database.                                                                                                                           

Methods: The UNOS database (2000-2021) was queried for all isolated orthotopic heart transplants in patients ≥18 years old. Pre-operative variables (n = 139) were evaluated with stepwise logistic regression; 47 significant factors were used in survival tree modeling. Graft survival time less than 7 days and instances of graft failure were excluded. Data were split into training (70%) and testing (30%) sets for modeling and further validated with ten-fold cross validation. Survival tree pruning and model selection was determined using AIC and log-likelihood. Log-rank pairwise comparisons between subgroups and estimated survival probabilities were calculated.                                                                                                                                  

Results: A total of 44,709 heart transplant patients were included for analysis. Logistic regression AUC = 0.768, F1 = 0.812; survival tree modeling returned 7 significant factors: recipient age, hospital length of stay, recipient diabetes, recipient education level, recipient primary payor source, prior cardiac surgery at transplant listing, and recipient functional status at time of transplant. Seventeen subgroups consisting of combinations of these factors were identified with distinct Kaplan-Meier survival curves (Figure 1) with five and ten-year estimated survival probability. 

Conclusions: Survival tree modeling is an innovative and flexible approach to understand the complex interactions between covariates on heart transplant survival. Individualized estimated survival probability following cardiac transplant may be possible with this technique, allowing for more cogent medical decision making and coherent patient and family counseling. 

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The downtrending cost of robotic bariatric surgery: a cost analysis of 47,788 bariatric patients

Effect of low-level creatinine clearance on short-term postoperative complications in patients with colorectal cancer

Meagan D Read, Johnathan Torikashvili, Haroon Janjua, Emily A Grimsley , Paul C Kuo, Salvatore Docimo

Background: The surgical robot is assumed to be a fixed, indirect cost. We hypothesized rising volume of robotic bariatric procedures would decrease cost per patient over time.

Methods: Patients who underwent elective, initial gastric bypass (GB) or sleeve gastrectomy (SG) for morbid obesity were selected from Florida Agency for Health Care Administration database from 2017 to 2021. Inflation-adjusted cost per patient was collected. Cost-over-time ($/patient year) and change in cost-over-time were calculated for open, laparoscopic, and robotic cases. Linear regression on cost generated predictive parameters. Density plots utilizing area under the curve demonstrated cost overlap.

Results: Among 76 hospitals, 11,472 bypasses (223 open, 6885 laparoscopic, 4364 robotic) and 36,316 sleeves (26,596 laparoscopic, 9724 robotic) were included. Total cost for robotic was approximately 1.5-fold higher (p < 0.001) than laparoscopic for both procedures. For GB, laparoscopic had lower total ($15,520) and operative ($6497) average cost compared to open (total $17,779; operative $9273) and robotic (total $21,756; operative $10,896). For SG, laparoscopic total cost was significantly less than robotic ($10,691 vs. $16,393). Robotic GB cost-over-time increased until 2021, when there was a large decrease in cost (-$944, compared with 2020).

Conclusion: Robotic SG total cost-over time fluctuated but decreased significantly in 2021 (-$490 compared with 2020). While surgical costs rose significantly in 2020 for bariatric procedures, our study suggests a possible downward trend in robotic bariatric surgery as total and operative costs are decreasing at a higher rate than laparoscopic costs.

Keywords: Bariatric surgery; Robotic surgery; Surgical cost, robotic bariatric surgery. Read More

Chen WS, Lin J, Zhang WT, Chen WJ, Gabriel EM, Kuo PC, Caycedo-Marulanda A, Cai YQ, Chen XD, Wu WY. Background: Renal function is closely related to cancer prognosis. Since preoperative renal insufficiency has been identified as a risk factor for postoperative complications, this study aimed to investigate the effect of preoperative creatinine clearance rate (CrCl) on short-term prognosis of patients undergoing colorectal surgery.

Methods: A retrospective analysis was conducted of the electronic health records of 526 adult patients who underwent elective colorectal cancer (CRC) surgery from September 2014 to February 2019 at the First Affiliated Hospital of Wenzhou Medical University. Cases were divided into two groups according to CrCl level and clinical variables were compared. Risk factors associated with postoperative complications were evaluated through univariate and multivariate logistic regression analyses.

Results: A total of 526 patients met the inclusion criteria. The overall rate of postoperative complications was 28.14%. Overall, the incidence of postoperative complications was significantly higher in the low CrCl patients. A low-level CrCl, multi-organ combined resection, and Charlson comorbidity index (CCI) were independent risk factors for short-term complications in patients with CRC. However, a low CrCl was identified as an independent risk factor for short-term postoperative complications in elderly, but not young patients in a subgroup analysis.

Conclusions: Preoperative low-level CrCl, multi-organ combined resection, and CCI were significant risk factors of postoperative complications in CRC patients. Preoperative low-level CrCl and multi-organ combined resection has a poor prognostic impact for elderly patients with CRC. These findings should have important implications for health care decision-making among patients with CRC who are at higher risk for post-operative complications.

Keywords: Outcomes; hospitalization cost; malignant tumor; renal function. Read More

Creating an integrated strategic plan

A of analytics and B of big data in healthcare research: Telling the tale of health outcomes research from the eyes of data

Christopher DuCoin, Paul C Kuo

Abstract: The modern surgical leader now requires many tools for successful leadership. One critical tool is developing an integrated strategic plan where team and culture are developed with a directed common mission. This mission or strategic plan must fit within certain constraints, such as the larger institutional goals and constrained resources. To help develop this strategic plan, the surgical leader has many resources to use. The most common strategic planning tool is the Strengths, Weaknesses, Opportunities, and Threats analysis. Here, both internal and external factors are evaluated. From here, the contribution will review the Political, Economic, Social, Technological, Legal, and Environmental analysis (ideal for external factors) and Mission, Objectives, Strategies and Tactics analysis (ideal for internal factors), along with the Blue Ocean Strategy, Scenario Planning, and Ansoff Matrix, all of which are excellent for future planning. Porter's Five Forces will review standard competing forces, whereas Six Sigma reviews measurable process development, and Balanced Scorecard provides the framework for measurable advancements. After the paper, the reader will better understand the various tools that can be used to develop an integrated strategic plan.   

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Haroon M Janjua, Michael Rogers, Meagan Read, Emily A Grimsley, Paul C Kuo

Introduction: With the availability of sophisticated data science algorithms on free, open-source platforms such as R and Python, Big Data and predictive analytics are increasingly utilized by the healthcare research community. Herein, we aim to articulate and explain the various steps in performing health outcomes research using Big Data, data science, predictive analytics, and machine learning (ML) algorithms. Healthcare research is a multi-faceted process involving various elements, including data acquisition, construction of a data analysis plan, data cleaning and preprocessing, modeling, and finally, the presentation of research findings. It involves analyzing data to study patient demographics and health. When using big data for healthcare research, data quality should be evaluated to determine its usefulness for any project, including consistency, accuracy, completeness, and metadata. Superior quality data are consistent and standardized, i.e., there is not a lot of variation in the measurement of the data elements. Data completeness is another critical feature, as missing data can affect model accuracy and require imputation, all of which shape the reliability of analyses. Clinical datasets encompass various data types and may be collected through surveys, electronic health records, and/or claims. Some contain information on patient health, demographics, socio-economic status, social determinants of health, hospital profiles, and physician information, among other healthcare factors.

Conclusion: In conclusion, data is the driving force in predictive analytics, ML, and Big Data. The quality and availability of data are vital to the growth of the healthcare research sector and focus should be given to building platforms to ease access to this gold.

Keywords: Administrative dataset; Big data; Healthcare analytics; Healthcare research; Machine learning Read More

Is Non-operative Management of Appendicitis Inferior in the COVID-19 Era?

Emily A Grimsley, Michael P Rogers, Haroon M Janjua, Ricardo Pietrobon, Jose J Diaz, Paul C Kuo, Meagan D Read; N3C Consortium

Background: Previous studies on non-operative management of acute appendicitis indicated comparable outcomes to surgery, but the effect of COVID-19 infection on appendicitis outcomes remains unknown. Thus, we evaluate appendicitis outcomes during the COVID-19 pandemic to determine the effect of COVID-19 infection status and treatment modality. We hypothesized that active COVID-19 patients would have worse outcomes than COVID-negative patients, but that outcomes would not differ between recovered COVID-19 and COVID-negative patients. Moreover, we hypothesized that outcomes would not differ between non-operative and operative management groups, regardless of COVID-19 status.

Methods: We queried the National COVID Cohort Collaborative from 2020-2023 to identify adults with acute appendicitis who underwent operative or non-operative management. COVID-19 status was denoted: COVID-negative, -active, or -recovered. Intention to treat was utilized for non-operative management. Propensity score-balanced analysis was performed to compare outcomes within COVID groups, as well as within treatment modalities.

Results: A total of 37,868 patients were included: 34,866 COVID-negative, 2,540 COVID-active, and 460 COVID-recovered. COVID-active and -recovered less-often underwent operative management. Unadjusted, there was no difference in mortality between COVID groups for operative management. There was no difference in rate of failure of non-operative management between COVID groups. Adjusted analysis indicated, compared with operative, non-operative management carried higher odds of mortality and readmission for COVID-negative and -active patients.

Conclusions: This study demonstrates higher odds of mortality amongst non-operative management of appendicitis, and near equivalent outcomes for operative management regardless of COVID-19 status. We conclude that non-operative management of appendicitis is associated with worse outcomes for COVID-active and -negative patients. Additionally, we conclude that a positive COVID test or recent COVID-19 illness alone should not preclude a patients from appendectomy for acute appendicitis. Surgeon clinical judgement of a patient's physiology and surgical risk should, of course, inform the decision to proceed to the operating room. Read More

Patient outcomes and cost in robotic emergency general surgery

Emily A Grimsley, Haroon M Janjua, Thomas Herron, Meagan D Read, Steven Lorch, John Y Cha, Sandra M Farach, Geoffrey P Douglas, Paul C Kuo

Background: The use of robotic technology in general surgery continues to increase, though its utility for emergency general surgery remains under-studied. This study explores the current trends in patient outcomes and cost of robotic emergency general surgery (REGS). Methods: The Florida Agency for Healthcare Administration database (2018-2020) was queried for adult patients undergoing intra-abdominal emergency general surgery within 24 h of admission and linked to CMS Cost Reports/Hospital Compare, American Hospital Association, and Rand Corporation Hospital datasets. Patients from the four most common REGS procedures were propensity matched to laparoscopic equivalents for hospital cost analysis. A telephone survey was performed with the top 10 REGS hospitals to identify key qualities for successful REGS programs. 181 hospitals (119 REGS, 62 non-REGS) performed 60,733 emergency surgeries. Six-percent were REGS. Results: The most common REGS were cholecystectomy, appendectomy, inguinal and ventral hernia repairs. Before and after propensity matching, total cost for these four procedures were significantly higher than their laparoscopic equivalents, which was due to higher surgical cost as the non-operative costs did not differ. There were no differences in mortality, individual complications, or length of stay for most of the four procedures. REGS volume significantly increased each year. Conclusion: The survey found that 8/10 hospitals have robotic-trained staff available 24/7. Although REGS volume is increasing in Florida, cost remains significantly higher than laparoscopy. Given higher costs and lack of significantly improved outcomes, further study should be undertaken to better inform which specific patient populations would benefit from REGS. Read More

Interpretable machine learning accurately reclassifies lobectomy surgical approaches by cost

Michael P Rogers, Haroon Janjua, Meagan Read, Ricardo Pietrobon, Paul C Kuo

Background: The volume of robotic lung resection continues to increase despite its higher costs and unproven superiority to video-assisted thoracoscopic surgery. We evaluated whether machine learning can accurately identify factors influencing cost and reclassify high-cost operative approaches into lower-cost alternatives. Methods: The Florida Agency for Healthcare Administration and Centers for Medicare and Medicaid Services Hospital and Physician Compare datasets were queried for patients undergoing open, video-assisted thoracoscopic surgery and robotic lobectomy. K-means cluster analysis was used to identify robotic clusters based on total cost. Predictive models were built using artificial neural networks, Support Vector Machines, Classification and Regression Trees, and Gradient Boosted Machines algorithms. Models were applied to the high-volume robotic group to determine patients whose cost cluster changed if undergoing a video-assisted thoracoscopic surgery approach. A local interpretable model-agnostic explanation approach personalized cost per patient. Results: Of the 6,618 cases included in the analysis, we identified 4 cost clusters. Application of artificial neural networks to the robotic subgroup identified 1,642 (65%) cases with no re-assignment of cost cluster, 583 (23%) with reduced costs, and 300 (12%) with increased costs if they had undergone video-assisted thoracoscopic surgery approach. The 5 overall highest cost predictors were patient admission from the clinic, diagnosis of metastatic cancer, presence of cancer, urgent hospital admission, and dementia.

Conclusion: K-means cluster analysis and machine learning identify a patient population that may undergo video-assisted thoracoscopic surgery or robotic lobectomy without a significant difference in total cost. Local interpretable model-agnostic explanation identifies individual patient factors contributing to cost. Application of this modeling may reliably stratify high-cost patients into lower-cost approaches and provide a rationale for reducing expenditure. Read More

COVID-Induced Alterations in Surgical Care and Outcomes in Perforated Diverticulitis

Emily A Grimsley, Haroon M Janjua, Meagan D Read, Paul C Kuo

Background: COVID-19 caused healthcare systems to significantly alter processes of care. Literature on the pandemic's effect on healthcare processes and resulting surgical outcomes is lacking. This study aims to determine outcomes of open colectomy in patients with perforated diverticulitis during the pandemic. Methods: Using CDC data, the highest and lowest COVID mortality rates were calculated and used to establish 9-month COVID-heavy (CH) and COVID-light (CL) timeframes, respectively. Nine-months of 2019 were assigned as pre-COVID (PC) control. Florida AHCA database was utilized for patient-level data. Primary outcomes were length of stay (LOS), morbidity, and in-hospital mortality. Stepwise regression with 10-fold cross-validation determined factors most impacting outcomes. A parallel analysis excluding COVID-positive patients was performed to differentiate COVID-infection from processes of care. Results: There were 3862 patients in total. COVID-positive patients had longer LOS, more intensive care unit admissions, and higher morbidity and mortality. After excluding 105 COVID-positive patients, individual outcomes were not different per timeframe. Regression showed timeframe did not affect primary outcomes. Discussion: Outcomes following colectomy for perforated diverticulitis were worse for COVID-positive patients. Despite increased stress on the healthcare system during the pandemic, major outcomes were unchanged for COVID-negative patients. Our results indicate that despite COVID-associated changes in processes of care, acute care surgery can still be performed in COVID-negative patients without increased mortality and minimal change in morbidity. Keywords: acute care surgery; colorectal; surgical quality Read More

Association of state-level factors with rate of firearm-related deaths

Emily A Grimsley, Meagan D Read, Michelle Y McGee, Johnathan V Torikashvili, Noah T Richmond, Haroon M Janjua, Paul C Kuo 

Background: Over 48,000 people died by firearm in the United States in 2021. Firearm violence has many inciting factors, but the full breadth of associations has not been characterized. We explored several state-level factors including factors not previously studied or insufficiently studied, to determine their association with state firearm-related death rates.

Methods: Several state-level factors, including firearm open carry (OC) and concealed carry (CC) laws, state rank, partisan lean, urbanization, poverty rate, anger index, and proportion of college-educated adults, were assessed for association with total firearm-related death rates (TFDR). Secondary outcomes were firearm homicide (FHR) and firearm suicide rates (FSR). Exploratory data analysis with correlation plots and ANOVA was performed. Univariable and multivariable linear regression on the rate of firearm-related deaths was also performed.

Results: All 50 states were included. TFDR and FSR were higher in permitless OC and permitless CC states. FHR did not differ based on OC or CC category. Open carry and CC were eliminated in all three regression models due to a lack of significance. Significant factors for each model were: 1) TFDR – partisan lean, urbanization, poverty rate, and state ranking; 2) FHR – poverty rate; 3) FSR – partisan lean and urbanization. Conclusions: Neither open nor concealed carry is associated with firearm-related death rates when socioeconomic factors are concurrently considered. Factors associated with firearm homicide and suicide differ and will likely require separate interventions to reduce firearm-related deaths. Key message: Neither open carry nor concealed carry law are associated with total firearm-related death rate, but poverty rate, urbanization, partisan lean, and state ranking are associated. When analyzing firearm homicide and suicide rates separately, poverty rate is strongly associated with firearm homicide rate, while urbanization and partisan lean are associated with firearm suicide rate. Keywords: Firearm-related deaths, Firearm-related mortality, Firearm violence, Gun violence, Gun-related mortality, Gun-related deaths Read More

Nonelective coronary artery bypass graft outcomes are adversely impacted by Coronavirus disease 2019 infection, but not altered processes of care: A National COVID Cohort Collaborative and National Surgery Quality Improvement Program analysis

Emily A Grimsley, Johnathan V Torikashvili, Haroon M Janjua, Meagan D Read, Anai N Kothari, Nate B Verhagen, Ricardo Pietrobon, Paul C Kuo, Michael P Rogers; N3C Consortium

Objective: The effects of Coronavirus disease 2019 (COVID-19) infection and altered processes of care on nonelective coronary artery bypass grafting (CABG) outcomes remain unknown. We hypothesized that patients with COVID-19 infection would have longer hospital lengths of stay and greater mortality compared with COVID-negative patients, but that these outcomes would not differ between COVID-negative and pre-COVID controls. Methods: The National COVID Cohort Collaborative 2020-2022 was queried for adult patients undergoing CABG. Patients were divided into COVID-negative, COVID-active, and COVID-convalescent groups. Pre-COVID control patients were drawn from the National Surgical Quality Improvement Program database. Adjusted analysis of the 3 COVID groups was performed via generalized linear models. Results: A total of 17,293 patients underwent nonelective CABG, including 16,252 COVID-negative, 127 COVID-active, 367 COVID-convalescent, and 2254 pre-COVID patients. Compared to pre-COVID patients, COVID-negative patients had no difference in mortality, whereas COVID-active patients experienced increased mortality. Mortality and pneumonia were higher in COVID-active patients compared to COVID-negative and COVID-convalescent patients. Adjusted analysis demonstrated that COVID-active patients had higher in-hospital mortality, 30- and 90-day mortality, and pneumonia compared to COVID-negative patients. COVID-convalescent patients had a shorter length of stay but a higher rate of renal impairment.

Conclusions: Traditional care processes were altered during the COVID-19 pandemic. Our data show that nonelective CABG in patients with active COVID-19 is associated with significantly increased rates of mortality and pneumonia. The equivalent mortality in COVID-negative and pre-COVID patients suggests that pandemic-associated changes in processes of care did not impact CABG outcomes. Additional research into optimal timing of CABG after COVID infection is warranted.

Keywords: COVID-19; nonelective coronary artery bypass grafting; outcomes; pandemic. Read More

Artificial Intelligence in Surgical Research: Accomplishments and Future Directions

Michael P Rogers, Haroon M Janjua, Steven Walczak, Marshall Baker, Meagan Read, Konrad Cios, Vic Velanovich, Ricardo Pietrobon, Paul C Kuo

Objective: The study introduces various methods of performing conventional ML and their implementation in surgical areas, and the need to move beyond these traditional approaches given the advent of big data. Investigate current understanding and future directions of machine learning applications, such as risk stratification, clinical data analytics, and decision support, in surgical practice. Summary background data: The advent of the electronic health record, near unlimited computing, and open-source computational packages have created an environment for applying artificial intelligence, machine learning, and predictive analytic techniques to healthcare. The "hype" phase has passed, and algorithmic approaches are being developed for surgery patients through all stages of care, involving preoperative, intraoperative, and postoperative components. Surgeons must understand and critically evaluate the strengths and weaknesses of these methodologies. Methods: The current body of AI literature was reviewed, emphasizing on contemporary approaches important in the surgical realm. Results and conclusions: The unrealized impacts of AI on clinical surgery and its subspecialties are immense. As this technology continues to pervade surgical literature and clinical applications, knowledge of its inner workings and shortcomings is paramount in determining its appropriate implementation. Keywords: Artificial intelligence; Big data; Machine learning. Read More

Machine Learning Analysis of Post-Laparoscopy Hernias and “I’m Leaving You to Close” Strategy

Jae Hwan Choi, Haroon Janjua, Konrad Cios, Michael P. Rogers, Meagan Read, MD, Salvatore Docimo Jr., Paul C. Kuo

Background: Contributing factors to post-laparoscopy hernia are unknown. We hypothesized that post-laparoscopy incisional hernias are increased when the index surgery was performed in teaching hospitals. Laparoscopic cholecystectomy was chosen as the archetype for open umbilical access. Materials and Methods: Maryland and Florida SID/SASD databases (2016-2019) was used to track one-year hernia incidence in both inpatient and outpatient settings, which was then linked to Hospital Compare, distressed communities index (DCI), and ACGME. Postoperative umbilical/incisional hernia following laparoscopic cholecystectomy were identified using CPT and ICD-10. Propensity matching and logistic regression techniques were utilized. Results: Postoperative hernia incidence was 0.2% (total=286; 261 incisional and 25 umbilical) in 117,570 laparoscopic cholecystectomy cases. Days to presentation (mean±SD) were incisional 141±92 and umbilical 66±74. Logistic regression performed best (AUC 0.75 (95% ci 0.67-0.82) and accuracy 0.68 (95% ci 0.60-0.75) using 10-fold cross validation) in propensity matched groups (1:1; n=279). Postoperative malnutrition (OR 3.5), hospital DCI of comfortable, mid-tier, at risk or distressed (OR 2.2 to 3.5), LOS > 1 day (OR 2.2), postop asthma (OR 2.1), hospital mortality below national average (OR 2.0) and emergency admission (OR 1.7) were associated with increased hernias. A decreased incidence was associated with patient location of small metropolitan areas with < 1 million residents (OR 0.5) and Charlson Comorbidity Index-Severe (OR 0.5). Teaching hospitals were not associated with postoperative hernia after laparoscopic cholecystectomy. Conclusions: Different patient factors as well as underlying hospital factors are associated with post-laparoscopy hernias. Performance of laparoscopic cholecystectomy at teaching hospitals is not associated with increased postoperative hernias. Keywords: laparoscopy, cholecystectomy, incisional hernia, postoperative complication, residency education Read More

Causal Analysis of Socioeconomic Influence on Cost of Care: The Emergency General Surgery Model

Meagan D. Read, Rohan Shah , Haroon Janjua , Salvatore Docimo , Emily A. Grimsley , McWayne Weche , Paul C. Kuo 

Background: This study characterizes the relationship between SES and cost of emergency general surgery (EGS). Methods: Utilizing Florida AHCA (2016-2020), patients undergoing the 7 most common EGS were identified. Distressed Community Index (DCI) was linked, which quantifies SES through unemployment, poverty, and other factors. Zipcodes are assigned DCI 0 (no distress) to 100 (severe distress). Linear regression with stepwise elimination was conducted. Top and bottom DCI quintiles were propensity matched for demographics, comorbidities, and procedure. Results: 144,924 admissions were included. Linear regression eliminated 5 of 28 variables, including DCI. Top cost contributors were discharge-43%; comorbidities-14%; age-9%. Distressed patients received less home health and inpatient rehab. Distressed patients utilized 4-/5-star hospitals less and had higher odds of mortality. Conclusion: Discharge, mortality, and hospital characteristics differ significantly between DCI communities. Total cost was similar, and is strongly influenced by discharge status, while DCI had no effect.

Keywords: distressed community index, emergency general surgery Read More

Determining The Value Proposition of Surgical Care in CMS Star Rated Hospitals

Cios K, MS, Janjua H, Rogers MP, Read M, Docimo S, Kuo PC

Background: CMS Hospital Quality Star ratings reflect the quality of care given to patients. It is hypothesized that increased Star-rating is associated with higher cost and that the value proposition is diminished. Methods: This study used the Florida AHCA inpatient dataset, CY2019. Partial colectomy was selected as a representative inpatient surgical procedure. Analysis was performed on this data to compare high and low Star-rated hospitals. Results: Total costs were equivalent among all Star levels on initial analysis. In a propensity matched comparison with 1 Star, 5 Star hospitals had significantly lower length-of-stay and ICU, anesthesia, radiology and lab costs, and conversely, had higher total (+2%), operating room and med-surg supply costs. Conclusions: These results demonstrate that total colectomy costs are functionally equivalent among the CMS 1- and 5- Star categories. The results indicate that higher CMS Star ratings fulfill the value proposition and indeed offer higher quality without significantly increased cost. Read More

Recipient Survival after Orthotopic Liver Transplantation: Interpretable Machine Learning Survival Tree Algorithm for Patient Specific Outcomes

Michael P. Rogers, Haroon M. Janjua, Meagan Read, Konrad Cios, Madan G.Kundu, Ricardo Pieterobon, Paul C. Kuo

Background: Elucidating contributors affecting liver transplant survival is paramount. Current methods offer crude global group outcomes. To refine patient-specific mortality probability estimation and determine covariate interaction using recipient and donor data, we generated a survival tree algorithm (ReSOLT) using UNOS transplant data.

Study design: The UNOS database was queried for liver transplants in patients ≥18 years old between 2000-2021. Pre-operative factors were evaluated with stepwise logistic regression; 43 significant factors were used in survival tree modeling. Graft survival <7 days was excluded. Data were split into training and testing sets and further validated with ten-fold cross validation. Survival tree pruning and model selection was achieved based on AIC and log-likelihood values. Log-rank pairwise comparisons between subgroups and estimated survival probabilities were calculated. Results: A total of 122,134 liver transplant patients were included for modeling. Multivariable logistic regression (AUC = 0.742, F1 = 0.822) and survival tree modeling returned 8 significant recipient survival factors: recipient age, donor age, recipient primary payment, recipient Hepatitis C status, recipient diabetes, recipient functional status at registration and at transplantation, and deceased donor pulmonary infection. Twenty subgroups consisting of combinations of these factors were identified with distinct Kaplan-Meier survival curves (p<0.001 among all by log rank test) with five-year and ten-year survival probabilities. Conclusions: Survival trees are a flexible and effective approach to understand the effects and interactions of covariates on survival. Individualized survival probability following liver transplant is possible with ReSOLT, allowing for more coherent patient and family counseling and prediction of patient outcome using both recipient and donor factors.

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Analysis of temporal Trends in Robotic Surgery Costs Using the Outpatient inguinal Hernia Repair Model

Read M, Janjua H, Rogers M, Kuo PC

Background: Robotic technology is increasingly utilized despite increased costs compared to laparoscopic procedures. As the robot is a fixed, indirect cost, we hypothesized increased volume of robotic procedures will decrease operative costs per patient. The model of same-day, unilateral, primary inguinal hernia (IH) surgery in males was chosen.

Methods: The Florida AHCA database was queried for IH repairs in 2015-2020. Inflation adjusted total and operative costs per patient were collected. Cost-over-time ($/patient/year) and change in cost-over-time were calculated for open, laparoscopic and robotic cases. Linear regression using cost as the dependent variable generated predictive parameters.

Results: 36,393 cases (19,364 open, 12,322 laparoscopic, 4,707 robotic) among 86 hospitals were included. 18 hospitals were “high volume”, defined as total robotic IH volume of >100 (range: 107-368) during the study period, and included 8,604 cases (3,915 open, 1,786 laparoscopic, 2,903 robotic). When compared to laparoscopic, total robotic cost and cost over time were 1.22- (p<0.001) and 1.5- fold higher (p<0.002). The change in cost-over-time was increased significantly in robotic cases: 358, 420, 548, 691, and 1542 $/pt/year for 2015 to 2020, respectively. Positive contributors to total hospital robotic costs were total robotic IH volume (17.3), total laparoscopic IH volume (12.6), and number of hospital beds (1.9). Total open IH volume was a negative contributor (-10). Conclusion: We conclude, in the short term, robotic surgical costs are not behaving as traditional fixed costs in outpatient, unilateral IH surgeries. Hospital methodology for cost assignment and increase robotic fixed costs such as purchase of additional instruments may explain these results. Key words: Robotic, laparoscopy, inguinal hernia, surgery, Cost trends, Robotic Costs Read More

A machine learning approach to high-risk cardiac surgery risk scoring

Rogers MC, Janjua H, Fishberger G, Harish A, Sukja J, Toloza E, DeSantis A, Hooker R, Pietrobon R, Lozonschi L, Kuo PC

Introduction: In patients undergoing high-risk cardiac surgery, the uncertainty of outcome may complicate the decision process to intervene. To augment decision-making, a machine learning approach was used to determine weighted personalized factors contributing to mortality. Methods: American College of Surgeons National Surgical Quality Improvement Program was queried for cardiac surgery patients with predicted mortality ≥10% between 2012 and 2019. Multiple machine learning models were investigated, with significant predictors ultimately used in gradient boosting machine (GBM) modeling. GBM-trained data were then used for local interpretable model-agnostic explanations (LIME) modeling to provide individual patient-specific mortality prediction. Results: A total of 194 patient deaths among 1291 high-risk cardiac surgeries were included. GBM performance was superior to other model approaches. The top five factors contributing to mortality in LIME modeling were preoperative dialysis, emergent cases, Hispanic ethnicity, steroid use, and ventilator dependence. LIME results individualized patient factors with model probability and explanation of fit. Conclusions: The application of machine learning techniques provides individualized predicted mortality and identifies contributing factors in high-risk cardiac surgery. Employment of this modeling to the Society of Thoracic Surgeons database may provide individualized risk factors contributing to mortality. Keywords: adult cardiac surgery; machine learning; model interpretability; risk scoring. Read More

Disparities in coronary artery bypass grafting between high- and low-volume surgeons and hospitals

Michael P. Rogers, Haroon M. Janjua, Paul C. Kuo

Background: High-volume surgeons and hospitals performing coronary artery bypass grafting have been associated with improved patient outcomes. However, patients of increased socioeconomic distress may have worse outcomes because of health care disparities. We sought to identify trends and outcomes in patients of elevated distress undergoing bypass grafting. Methods: The Florida Agency for Healthcare Administration administrative data set was merged with Centers for Medicare and Medicaid Services Physician and Hospital Compare and Economic Innovation Group Distressed Community Index data sets to build a comprehensive database. The data set was queried to identify patients undergoing coronary artery bypass procedures between 2016 and 2020. High- and low-volume hospitals and surgeons were compared. Patient and hospital demographics, comorbidities, length of stay, and postoperative complications were analyzed by χ2 and t test where appropriate. Results: A total of 41,571 coronary artery bypass grafting procedures were performed by 174 surgeons at 67 Florida hospitals. Low- and high-volume hospitals did not differ with respect to hospital ownership, overall star rating, national comparisons of mortality, readmission, or cost effectiveness. Patients from at-risk and distressed communities were more likely to undergo surgery at low-volume hospitals. Hospital length of stay was increased for low-volume hospitals (10.2 vs 9.4 days, P < .05). Postoperative complications including pneumonia, arrhythmia, respiratory failure, acute renal failure, shock, pleural effusion, and sepsis were more frequent at low-volume hospitals and for low-volume surgeons.

Conclusion: High-volume hospitals and surgeons have improved postoperative outcomes and hospital length of stay when compared to low-volume hospitals and surgeons performing coronary artery bypass grafting. At-risk and distressed populations are more likely to undergo bypass surgery at low-volume hospitals, potentially contributing to worse patient outcome. Efforts should be made to mitigate the potential impact of low socioeconomic status to improve outcomes in this population. Read More

Exploring the paradigm of robotic surgery and its contribution to the growth of surgical volume

Grimsley EA, Barry TM, Janjua H, Eguia E, DuCoin C, Kuo PC

Background: Robotic surgery is an appealing option for both surgeons and patients. The question around the introduction of new surgical technology, such as robotics, with the potential link to increased procedure-specific volume has not been addressed. We hypothesize that hospital adoption of robotic technology increases the total volume of specific procedures as compared to nonrobotic hospitals. Methods: The 2010–2020 Florida Agency for Health Care Administration Inpatient database was queried for open, laparoscopic, and robotic colectomy, lobectomy, gastric bypass, and antireflux procedures. International Classification of Diseases, 9th and 10th Revisions, codes were used. Difference in difference method was used to evaluate
the impact of robotics on total procedure-specific volume of robotic hospitals versus nonrobotic hospitals before and after adopting robotic technology. Incident rate ratios from the difference in difference analysis determined the significance of adding robotics. Patient demographics were evaluated using χ2 test. Results: A total of 291,826 procedures were performed at 217 hospitals, 151 with robotic capabilities. Robotic hospitals experienced a 37% increase in surgical volume due to robotic technology (incident rate ratio 1.37, P < .05), which was consistent for each surgery except antireflux procedures (incident rate ratio 0.95). Robotic procedures
had significantly higher charges for medical/surgical supplies; however, the mean length of stay for robotic procedures was significantly shorter than that of laparoscopic and open cases.

Conclusion: Hospital adoption of robotic technology significantly increases surgical volume for select procedures. Hospitals should consider the benefits of introducing robotic technology which leads to higher volume and decreased length of stay, benefitting both hospital systems and patients. Read More

Outcomes of Transcatheter and Surgical Aortic Valve Replacement in Distressed Socioeconomic Communities

Rogers MP, DeSantis AJ, Janjua HM Kulshrestha S, Kuo PC, Lozonschi L

Objective: Patients of low socioeconomic status have an increased risk of complications following cardiac surgery. We aimed to identify disparities in patients undergoing aortic valve replacement using the Distressed Communities Index (DCI), a comparative measure of community well-being. The DCI incorporates seven distinct socioeconomic indicators into a single composite score to depict the economic well-being of a community. Methods: The Healthcare Cost and Utilization Project State Inpatient Database (HCUP-SID) for Florida and Washington was queried to identify patients undergoing surgical and transcatheter aortic valve replacement (surgical aortic valve replacement [SAVR], transcatheter aortic valve replacement [TAVR]) between 2012-2015. Patients undergoing TAVR and SAVR were propensity-matched and stratified based on the quintile of DCI score. A distressed community was defined as those in quintiles 4 and 5 (at-risk and distressed, respectively); a non-distressed community was defined as those in quintiles 1 and 2 (prosperous and comfortable, respectively). Outcomes following aortic valve replacement were compared across groups in distressed communities. Propensity score matching was used to balance baseline covariates between groups. Results: A total of 27,591 patients underwent aortic valve replacement. After propensity matching, 5,331 patients were identified in each TAVR and SAVR group. Distressed TAVR patients had lower rates of postoperative pneumonia (7.6% vs. 3.8%, p<0.001), sepsis (3.6% vs. 1.9%, p<0.05), and cardiac complications (15.4% vs. 7.5%, p<0.001) when compared to highly distressed SAVR patients. When comparing distressed SAVR and TAVR and low distressed SAVR and TAVR groups, no significant difference was found in postoperative outcomes, except distressed TAVR experienced more cases of UTI. Conclusion: Highly distressed TAVR patients had lower incidences of postoperative sepsis, pneumonia, and cardiac complications when compared to the highly distressed SAVR cohort. Patients undergoing TAVR in highly distressed communities had an increased incidence of postoperative urinary tract infection. DCI may be a useful adjunct to current risk scoring systems.

Keywords: Aortic Valve Surgery, Socioeconomic Factors, Socioeconomic Determinants, Transcatheter Aortic Replacement, Adult Cardiac Surgery Read More

Machine Learning Refinement of the NSQIP Risk Calculator – Who Survives the “Hail Mary” Case?

Rogers MP, Janjua H, Anthony D, Emily G, Pietrobon R, Kuo PC.

Background: The ACS-NSQIP risk calculator helps guide operative decision making. In patients with significant surgical risk, it may be unclear whether to proceed with “Hail Mary” type interventions. To refine predictions, a local interpretable model-agnostic explanations machine (LIME) learning algorithm was explored to determine weighted patient-specific factors’ contribution to mortality. Study Design: The ACS-NSQIP database was queried for all surgical patients with mortality probability greater than 50% between 2012 and 2019. Pre-operative factors (n=38) were evaluated using stepwise logistic regression; 26 significant factors were used in gradient boosted machine (GBM) modeling. Data were divided into training and testing sets, and model performance substantiated with ten-fold cross validation. LIME provided individual subject mortality. The GBM-trained model was interpolated to LIME, and predictions made using the test dataset. Results: There were 6,483 deaths (53%) among 12,248 admissions. GBM modeling displayed good performance (AUC 0.65, 95% CI 0.636-0.671). The top 5 factors (% contribution) to mortality included: septic shock (27%), elevated INR (22%), ventilator-dependence (14%), thrombocytopenia (14%), and elevated serum creatinine (5%). LIME modeling subset personalized patients by factors and weights on survival. In the entire cohort, mortality positive predictive value with two factor combinations was 53.5% (specificity 0.713), three combinations 64.2% (specificity 0.835), four combinations 72.1% (specificity 0.943), and all five combinations 77.9% (specificity 0.993). Conversely, mortality positive predictive value fell to 34% in the absence of 4 factors. Conclusion: Through the application of machine learning algorithms (GBM and LIME), our model individualized predicted mortality and contributing factors with substantial ACS-NSQIP predicted mortality. Utilization of machine learning techniques may better inform operative decisions and family conversations in cases of significant surgical risk.

Keywords: machine learning, NSQIP, mortality prediction Read More

Predictive modeling of in-hospital mortality following elective surgery

Michael P. Rogers, Anthony J.DeSantis, Paul C. Kuo, Haroon M. Janjua

Introduction: The specific healthcare macroenvironment factors contributing to in-hospital mortality following elective surgery remain nuanced. We hypothesize an accurate global elective surgical mortality model can be created. Methods: FL AHCA and Hospital Compare (2016-2019) were queried for in-hospital mortality following elective surgeries. Stepwise logistic regression with 47 patient and hospital factors was followed by gradient boosting machine (GBM) modeling describing the relative influence on risk for in-hospital mortality. Deceased and surviving patients were matched (1:2) to perform univariate analysis and logistic regression of significant factors. Results: A total of 511,897 admissions, 2,266 patient deaths and 162 Florida hospitals were included. GBM factors (AUC 0.94) included post-operative patient and hospital factors. In the final regression model, patient age older than 70 years of age and hospital 5-star rating were significant (OR 2.87, 0.47, respectively). Hospitals rated 5-stars were protective of mortality.

Conclusion: In-patient mortality following elective surgery is influenced by patient and hospital level factors. Efforts should be made to mitigate these risks or enhance those that are protective. Keywords: Elective surgery; Hospital quality; In-hospital mortality; Machine learning; Predictive analytics Read More

Adopting Robotic Thoracic Surgery Impacts Hospital Overall Lung Resection Case Volume

Rogers MP, Janjua H, Eguia E, Lozonschi L, Toloza EM, Kuo PC.

Purpose: We sought to evaluate the role of robotic-assisted lung surgery on hospital volume using difference in difference (DID). We propose hospital adoption of robotic thoracic technology increases total volume of specific procedures as compared to non-robotic hospitals. Methods: The 2010-2015 Florida Agency for Health Care Administration dataset was queried for open, video-assisted thoracoscopic, and robotic-assisted thoracic surgeries. Incident Rate Ratios (IRR) from DID analysis determined the significance of robotic technology. For each technique, length of stay and elements of charges were compared to determine statistical significance. Results: A total of 28,484 lung resection procedures performed at 162 hospitals, 65 of which had robotic capabilities were included. Robotic hospitals experienced an 85% increase in total lung surgical volume (IRR 1.85, p-value <0.001). This increase in volume was consistent for each lung resection procedure separately Conclusion: Hospital adoption of robotic technology significantly increases the overall lung surgical volume for select lung resection procedures. Keywords: Robotics, hospital volume, difference in difference

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Introduction of Transcatheter Aortic Valve Replacement Technology Increases Overall Aortic Valve Surgical Volume: Evaluating the Florida Experience

Rogers MP, Janjua H, Eguia E, Lozonschi L, Kuo PC

Purpose: Transcatheter aortic valve replacement (TAVR) technology is increasingly utilized for aortic valve stenosis. We sought to evaluate the adoption of TAVR technology with respect to overall surgical aortic valve replacement (SAVR) volume in Florida. Methods: The 2010-2019 Florida Agency for Health Care Administration dataset was queried. DID analysis was used to evaluate the impact of TAVR on the total aortic valve surgical volume of TAVR versus non-performing hospitals. Length of stay and elements of charges were compared for the raw and 1:1 propensity matched data. Results: A total of 46,032 surgical aortic valve procedures were performed at 88 hospitals. TAVR performing hospitals experienced a 21% increase in total aortic valve surgical volume. Length of stay was significantly less for patients undergoing TAVR. Propensity matched TAVR patients had less gross total charges. Conclusion: Introduction of TAVR technology significantly increased overall surgical aortic valve volume and may be associated with less gross total hospital charges. Keywords: TAVR, Difference-in-difference, aortic valve replacement, aortic stenosis

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Elements of The Care Environment Influence Coronary Artery Bypass Surgery Readmission

Michael P. Rogers, Evelena Cousin-Peterson, Tara M. Barry, Marshall S. Baker, Paul C. Kuo, Haroon M. Janjua

Background: CABG 30-day unplanned readmission is a focus for the CMS Hospital Readmissions Reduction Program. Awareness of the critical elements of the care delivery environment, including hospital infrastructure and patient clinical profiles that predispose toward readmission, is essential to proactively decrease readmissions. Methods: The HCUP-SID, AHA, and HIMMS datasets were merged to create a single dataset of patient and hospital-level data from 8 states. Isolated CABG procedures were queried for all cause 30-day readmission and backwards stepwise logistic regression performed. Readmission rate was then used to categorize hospitals into quartiles and analysis focused on the hospitals with the lowest (Q1) and highest (Q4) readmission rates. Univariate analysis was performed comparing Q1 and Q4 hospitals. Results: A total of 150,215 patients underwent isolated CABG with 23,244 (15.5%) readmitted patients among 903 hospitals. Model AUC was 0.709 (95% CI, 0.702-0.716), with the top three readmission determinants related to discharge disposition. Compared to Q1, Q4 patients were more often female, > 70 years of age, and had Medicare as a primary payor (p < 0.001). Low readmission rate hospitals were characterized by higher costs, not for-profit status, having Joint Commission accreditation, and higher total admissions, operative volume, hospital/ICU beds, full time physicians, nurses, and ancillary personnel (p < 0.001). Conclusion: Readmission after CABG is strongly influenced by discharge disposition. However, hospital factors such as scale, personnel, and ownership structure are significant contributors to readmission. Focus beyond patient factors to include the entire continuum of care is required to enhance outcomes, of which readmission is one surrogate measure.

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Identifying and Mitigating Factors Contributing to 30-Day Hospital Readmission in High Risk Patient Populations

Rogers MP, Kuo PC

Unanticipated hospital readmission may significantly impact patient quality of life, hospital system resource utilization, and healthcare expenditure. The cost of unplanned hospital readmission is estimated between $20–40 billion dollars annually in the United States (1,2). Particular conditions have been identified to contribute disproportionally to readmission and include congestive heart failure (CHF), septicemia, and pneumonia (2). Accordingly, significant attempts have been made to identify and mitigate factors contributing to 30-day hospital readmission. Efforts by the Centers for Medicare and Medicaid Services (CMS) Hospital Readmissions Reduction Program (HRRP), Joint Commission on Accreditation of Healthcare Organizations (JCAHO) performance metrics, and readmission rates as a measure of quality and hospital financial performance have endeavored to reduce unnecessary readmissions to the benefit of patients and hospitals alike (3). Robust national datasets have allowed researchers to identify predictors of hospital readmission unique to individual diagnoses and procedures (4-7). Consequently, readmission rates declined from 21.5% in 2007 to 17.8% in 2015 for conditions targeted by CMS, and from 15.3% to 13.1% for non-targeted conditions (8). As reimbursement and quality metrics are increasingly tied to patient outcome (i.e., mortality, infection, and unplanned 30-day readmission), interest in further identifying contributing factors remains a priority.

Reducing unplanned 30-day hospital readmission remains a priority for patients, physicians, healthcare systems, and payors alike. It is estimated that approximately one-third of readmissions in this cohort may be preventable (22). These events significantly impact patient quality of life, hospital system resource utilization, and overall healthcare cost. Identifying potential patient and hospital factors that may reduce these readmissions is therefore of significant consequence. Garg and colleagues are to be congratulated on their excellent contribution to the literature and in providing insight on the contributors to readmission in this previously understudied cohort using a large nationally representative database.

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Does Adoption of New Technology Increase Surgical Volume? The Robotic Inguinal Hernia Model

Tara M. Barry, Haroon M. Janjua, Christopher DuCoin, Emanuel Eguia, Paul C. Kuo

Introduction: Robotic Inguinal Hernia repair has been associated with higher costs but shorter length of stay. Robotic surgery is an appealing option for patients undergoing elective hernia surgery however given the high startup, maintenance and operating costs, the adoption of robotic technology may not guarantee increased profitability. Our hypothesis is that the introduction of robotic technology increases the overall surgical volume of inguinal hernia repairs within a hospital as compared to non-robotic hospitals.

Methods: The 2010-2018 Florida Agency for Health Care Administration Ambulatory Patient data was queried for Open, Laparoscopic and Robotic inguinal hernia repairs using ICD9, ICD10 and CPT codes. Using a difference in difference (DID) technique, we determined the difference of the total hernia volume of robotic hospitals pre- and post- adoption of robotic technology. In addition, selected hospitals which were early adopters of robotic technology were compared to with their surrounding nonrobotic competitor hospitals. Incident Rate Ratios- IRR, from the difference in difference analysis determined the significance of robotic technology. Hospital and patient demographic data were evaluated, and chi square test were used to determine statistical significance. p < 0.05 was considered significant.

Results: There were a total of 258,785 inguinal hernia repairs (5,774 Robotic, 88,265 Laparoscopic and 164,746 Open) performed at 398 hospitals, 94 of which had robotic capabilities. Of all the procedure types, around 90% were primary inguinal hernia repairs. Majority of patients in this cohort were white non-Hispanic or Latino males (85%, 84%, 92%), age group 51-70(46%), holding commercial health insurance (43%) and belonged to lowest Charlson comorbidity level (82%). Facility types designation for almost all robotic hospitals was hospital (99%), whereas 65% of non-robotic hospitals were ambulatory surgery centers and all other hospitals. Robotic hospitals experienced a 9.5% increase in total volume of inguinal hernia repairs after introduction of robotic technology (Incident Rate Ratios- IRR 1.095, p value <0.0001). A significant increase in total hernia volume was observed for the early adopter hospitals with the IRR(s) ranging 1.20-2.51(all p values < 0.0001), implying that adoption of robotic technology can in fact lead to very significant increase in total hernia volume for a hospital.

Conclusion: The introduction of robotic technology leads to an increase in the overall volume of inguinal hernia repairs performed at a given hospital. To further evaluate the impact of robotic technology and significance of this methodology, additional work is underway by using additional procedures and data from other states.

Key words: Robotic, laparoscopy, inguinal hernia, surgery, case volume, difference in difference

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Discharge timing: Does targeting an ideal length of stay for patients undergoing colectomy impact readmissions and costs of care?

Evelena Cousin-Peterson, Haroon M Janjua, Tara M Barry, Marshall S Baker, Paul C Kuo

Introduction: In colorectal surgery, enhanced recovery protocols reduce length-of-stay (LOS). Concerns remain about increased readmission rates. Using a predictive model targeting ideal LOS (iLOS), we evaluate the impact of discharge timing on readmission. Methods: The HCUP-SID and AHA databases combined patient and hospital-level data from four states. Colectomy patients were stratified and propensity-matched based. We predicted iLOS using multivariate linear regression, created a discharge timing variable and used multivariate logistic regression to analyze 30-day and 90-day readmissions. Results: Of 100,701 patients, 6903 (6.85%) were Lap-Left, 16,883 (16.77%) were Open-Left, 32,173 (31.95%) were Lap-Right, and 44,742 (44.43%) were Open-Right. Very early discharge (>4d before iLOS) and very late discharge (>4d after iLOS) were predictors of readmission in Lap- Left (p < 0.05) and Open-Right (p < 0.05). In Lap-Right, early discharge was a significant predictor of readmission (p < 0.01). Conclusion: Targeting using iLOS may optimize discharge timing after colectomy and avoid unplanned readmissions. Keywords: Colectomy; Cost; Ideal length of stay; Predictive modeling; Readmission.

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Pain as the Fifth Vital Sign

Michael P Rogers, Paul C Kuo

Devastating consequences of the opioid epidemic, including prescription misuse, opioid overdose, and the rising incidence of newborns experiencing withdrawal symptoms, continue to plague communities in the US. In 2017, the Department of Health and Human Services declared a Public Health Emergency to address the national opioid crisis and unveiled a 5-point Opioid Strategy to combat the epidemic.1 Despite these efforts, available data suggest enough opioid prescriptions are written each year for half of all Americans to receive one. According to the CDC, more than 1 in 5 Americans had an opioid prescription filled in 2018.2 Shockingly, in the same year nearly 40 people died per day after taking prescription opioids. Rates of opioid misuse range from 21% to 29% by some estimates, with addiction developing in approximately 8% of those prescribed opioids.3 Uniquely, surgeon's prescribing habits, especially in the outpatient ambulatory surgery domain, can play an integral role in battling this ongoing health crisis.

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Do high-volume centers mitigate complication risk and reduce costs associated with performing pancreaticoduodenectomy in ethnic minorities?

Emanuel Eguia, Gerard V Aranha, Gerard Abood, Constantine Godellas, Paul C Kuo, Marshall S Baker

Introduction: Few studies examine the impact of ethnicity on post-operative outcomes and costs associated with pancreaticoduodenectomy (PD). Methods: Multivariable regression (MVR) was used to perform a risk-adjusted comparison of patients within the Healthcare Cost and Utilization Project Databases undergoing PD. Results: 4742 patients underwent PD. 3871 (81%) were white, 456 (10%) black, and 415 (9%) Hispanic. Black and Hispanics were less likely than whites to undergo PD in high volume centers. Blacks and Hispanics had a higher risk of select post-operative complications, prolonged lengths of stay, and high-cost outliers. When PDs done in high volume centers were evaluated separately, blacks and Hispanics had a lower adjusted-risk of any serious morbidity (OR 0.44, 95% CI [0.33, 0.57], OR 0.56, 95% CI [0.43, 0.73]) than whites but costs for PD among the three ethnic groups were statistically identical. Conclusion: Racial and ethnic minorities undergoing PD are less likely to receive care at high-volume centers, are at an increased risk of post-operative morbidity, and have higher odds of being high-cost outliers than NHW. Keywords: Benign and malignant pancreatic tumors; Cost-volume; Healthcare economics; Laparoscopic surgery; Pancreaticoduodenectomy.

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The Impact of the Affordable Care Act Medicaid Expansion on Vascular Surgery

Emanuel Eguia, Marshall S Baker, Carlos Bechara, Murray Shames, Paul C Kuo

Background: The Affordable Care Act (ACA) Medicaid expansion increased Medicaid eligibility such that all adults with an income level up to 138% of the federal poverty threshold in 2014 qualified for Medicaid benefits. Prior studies have shown that the ACA Medicaid expansion was associated with increased access to care. The impact of the ACA Medicaid expansion on patients undergoing complex care for major vascular pathology has not been evaluated. Methods: The Healthcare Cost and Utilization Project State Inpatient Database was used to identify patients undergoing care for major vascular pathology in 6 states from 2010 to 2014. The analysis cohort included adult patients between the ages of 18 and 64 years who underwent a nonemergent surgical procedure for an abdominal aortic aneurysm, thoracic aortic aneurysm, carotid artery stenosis, peripheral vascular disease, or chronic kidney disease. Poisson regression was used to determine the incidence rate ratios (IRRs). Results: There were a total of 83,960 patients in the study cohort. Compared with nonexpansion states, inpatient admissions for Medicaid patients with an abdominal or thoracic aneurysm and carotid stenosis diagnosis increased significantly (IRR, 1.20, 1.27, 1.06, respectively; P < 0.05) in states that expanded Medicaid. Vascular-related surgeries increased for carotid endarterectomy, lower extremity revascularization, lower extremity amputation, and arteriovenous fistula in expansion states (IRR, 1.24, 1.10, 1.11, 1.16, respectively; P < 0.05) compared with nonexpansion states. Conclusions: In states that expanded Medicaid coverage under the ACA, the rate of vascular-related surgeries and admissions for Medicaid patients increased. We conclude that expanding insurance coverage results in enhanced access to vascular surgery.

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Laparoscopic partial hepatectomy is cost-effective when performed in high volume centers: A five state analysis

Emanuel Eguia, Patrick J Sweigert, Ruojia Debbie Li, Paul C Kuo, Haroon Janjua, Gerard Abood, Marshall S Baker

Background: Prior studies comparing the efficacy of laparoscopic (LHR) and open hepatic resection (OHR) have not evaluated inpatient costs. Methods: We conducted a retrospective cohort study using the Healthcare Cost and Utilization Project State Inpatient Databases to identify patients undergoing hepatic resection between 2010 and 2014. Results: 10,239 patients underwent hepatic resection. 865 (8%) underwent LHR and 9374 (92%) underwent OHR. On adjusting for hospital volume, patients undergoing LHR had a lower risk of respiratory (OR 0.64, 95% CI [0.52, 0.78]), wound (OR 0.48; 95% CI [0.29, 0.79]) and hematologic (OR 0.57; 95% CI [0.44, 0.73]) complication as well as a lower risk of being in the highest quartile of cost (0.58; 95% CI [0.43, 0.77]) than those undergoing OHR. Patients undergoing LHR in very high volume (>314 hepatectomies/year) centers had lower risk-adjusted 90-day aggregate costs of care than those undergoing OHR (-$8022; 95% CI [-$11,732, -$4311). Discussion: Laparoscopic partial hepatectomy is associated with lower risk of postoperative complication than OHR. This translates to lower aggregate costs in very high-volume centers. Keywords: Cost-volume; Healthcare economics; Hepatectomy; Laparoscopic surgery.

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Defining the relative contribution of health care environmental components to patient outcomes in the model of 30-day readmission after coronary artery bypass graft (CABG)

Haroon Janjua, Tara M Barry, Evelena Cousin-Peterson, Paul C Kuo

Background: Patient outcomes following health care interventions may be dependent on a variety of factors: patient, surgeon, hospital, information technology, and temporal, cultural, and socioeconomic factors, among others. In this study, we characterize the relative contribution of each of these factors using a model of 30-day readmission following coronary artery bypass graft. Methods: The Healthcare Cost and Utilization Project, the American Hospital Association Annual Health Survey Databases, the Healthcare Information and Management Systems Society, and the Distressed Communities Index from 2010 to 2013 were linked for Florida, Iowa, Massachusetts, Maryland, New York, and Washington. Logistic regression, random forest, decision tree, gradient boosting, k-nearest-neighbors classification, and XGBoost tree models were implemented. Modeling results were compared on the basis of predictive accuracy, sensitivity, specificity, and area under the curve. Decision tree performed best and was selected for further analysis. A gradient-boosted model was used to quantify factor contribution. Results: The model had 45,352 patients, 54,096 admissions, and a 16.2% 30-day readmission rate after coronary artery bypass graft. The top 10 predictors were disposition at discharge, number of chronic conditions, total procedures, median household income, adults without high school diplomas, primary payer method, Agency for Healthcare Research and Quality comorbidity: renal failure, patient location (urban-rural), admission type, and age categories. The top 3 socioeconomic predictors were estimated state median household income, adults without high school diplomas, and patient location (urban versus rural designation). The relative contribution of patient/temporal, socioeconomic, hospital information technology, and hospital factors to readmission is 83.45%, 5.71%, 6.34%, and 4.31%, respectively. Conclusion: In this model, the contribution of socioeconomic factors is substantive but lags significantly behind patient/temporal factors. With ever increasing availability of data, identification of contributors to patient outcomes within the overall health care macroenvironment will allow prioritization of interventions.

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State-Level Examination of Clinical Outcomes and Costs for Robotic and Laparoscopic Approach to Diaphragmatic Hernia Repair

Sujay Kulshrestha, Haroon M Janjua, Corinne Bunn, Michael Rogers, Christopher DuCoin, Zaid M Abdelsattar, Fred A Luchette, Paul C Kuo, Marshall S Baker

Background: Published studies evaluating the effect of robotic assistance on clinical outcomes and costs of care in diaphragmatic hernia repair (DHR) have been limited. Study design: The Healthcare Cost and Utilization Project State Inpatient and State Ambulatory Surgery and Services Databases for Florida were queried to identify patients undergoing transabdominal DHR between 2011 and 2018 and associated inpatient and outpatient encounters within 12 months after the index operation. Patients undergoing robotic DHR were 1:1:1 propensity score-matched for age, sex, race, Elixhauser comorbidity score, case priority, payer, and facility volume with patients undergoing open and laparoscopic DHR. Results: There were 5,962 patients (67.3%) who underwent laparoscopic DHR, 1,520 (17.2%) who underwent open DHR, and 1,376 (15.5%) who underwent robotic DHR. On comparison of matched cohorts, median index length of stay (3 days; interquartile range [IQR] 2 to 5 days vs 2 days; IQR 1 to 4 days; p < 0.001) and index hospitalization costs ($17,236; IQR $13,231 to $22,183 vs $12,087; IQR $8,881 to $17,439; p < 0.001) for robotic DHR were greater than for laparoscopic DHR. Median length of stay for open DHR (6 days; IQR 4 to 10 days) was longer than that for both laparoscopic and robotic DHR. Median index hospitalization costs for open DHR ($16,470; IQR $11,152 to $23,768) were greater than those for laparoscopic DHR, but less than those for robotic DHR. There were no significant differences between cohorts in the overall rate of post-index care. Conclusions: Laparoscopic DHR is the most cost-effective approach to DHR. Robotic assistance provides clinical outcomes comparable with laparoscopic DHR, but is associated with increased index cost.

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Prejudices of a Referenced Philosopher

Yusur M. Alsalihi, Evelena Cousin-Peterson, Paul C. Kuo, 

To the Editor The message of "social solidarity" and collaboration in Dr Berwick's Viewpoint was eloquent. Unfortunately, it was undermined by referencing a philosopher, Immanuel Kant, whose "racist and sexist prejudices had a profound impact on the shape of his moral and political theory." The Kant reference to the "moral law within" that underscored the entire article was misrepresented in a way that gave a skewed perception of its meaning. Kant's moral law is unconditional rationality even in distress. Kant thought that individuals who can rationalize can be moral and, while he writes that his concepts are applicable to all persons, he makes it clear who is a "person" and a "sub-person." He characterized White women as having to be guided toward morality, stating that "I hardly believe that the fair sex is capable of principles," while characterizing female scientists as aberrations. On race, he perpetuated a racial hierarchy that "[Native] Americans and Negroes cannot be educated or govern themselves. Thus, serve only as slaves" and that "the inhabitants of India" were incapable of abstract thinking and not suited for leadership roles. Alternatively, consider the works of modern philosopher Charles W. Mills, who further developed Kantianism by including inclusive insight about modern ethics and morality, or Elvira Basevich, who expanded Kant's model of public reason to develop a model of interracial civic fellowship. Authors have a shared responsibility to educate and avoid perpetuating a skewed understanding of the racist and discriminatory ideologies woven into the fabric of the status quo; the "vested interests in the health care system," the "economic and lobbying forces of the investment community and multinational corporations," and the "political cards stacked against profound change." By being accountable to this responsibility, meaningful steps can be taken toward Berwick's morally guided campaign.

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Carotid Body Tumor Resection: Just as Safe without Preoperative Embolization

Adrienne N Cobb, Adel Barkat, Witawat Daungjaiboon, Pegge Halandras, Paul Crisostomo, Paul C Kuo, Bernadette Aulivola

Background: Carotid body tumors (CBTs) are rare entities for which surgical resection remains the gold standard. Given their hypervascularity, preoperative embolization is often used; however, controversy exists over whether a benefit is associated. Proponents of embolization argue it minimizes blood loss and complications. Critics argue cost and stroke outweigh benefits. This study aimed to investigate the impact of embolization on outcomes after CBT resection. Methods: Patients undergoing CBT resection were identified using the Healthcare Cost and Utilization Project State Inpatient Database for 5 states during the years 2006-2013. Patients were divided into 2 groups: carotid body tumor resection alone (CBTR) and carotid body embolization prior to tumor resection (CBETR). Descriptive statistics were calculated using arithmetic means with standard deviations for continuous and proportions for categorical variables. Patients were propensity score matched on the basis of sex, age, race, insurance, and comorbidity before analysis. Risk-adjusted odds of mortality, stroke, nerve injury, blood loss, and length of stay (LOS) were calculated using mixed-effects regression models with fixed effects for age, race, sex, and comorbidities. Results: A total of 547 patients were identified. Of these, 472 underwent CBTR and 75 underwent CBETR. Mean age was 54.7 ± 16 years. Mean number of days between embolization and resection was 0.65 ± 0.72, (range 0-3) days. When compared to CBTR, there were no significant differences in mortality for CBETR (1.35 vs. 0% P = 0.316), cranial nerve injury (2.7 vs. 0% P = 0.48), and blood loss (2.7 vs. 6.8% P = 0.245). After risk adjustment, CBETR increased the odds of prolonged LOS (OR: 5.3; CI 2.1-13.3). Conclusions: CBT resection is a relatively rare procedure. The utility of preoperative tumor embolization has been questioned. This study demonstrates no benefit of preoperative tumor embolization.

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The impact of the affordable care act (ACA) Medicaid Expansion on access to minimally invasive surgical care

Emanuel Eguia, Marshall S Baker, Bipan Chand, Patrick J Sweigert, Paul C Kuo

Introduction: This study aims to evaluate the effect of the ACA Medicaid expansion on the utilization of minimally invasive (MIS) approaches to common general surgical procedures. Methods: We queried five Healthcare Cost and Utilization Project State Inpatient Databases to evaluate rates of utilization and costs of MIS and open approaches pre and post Medicaid expansion. Results: 117,241 patients met the inclusion criteria. Following the enactment of the ACA, use of both laparoscopic gastric bypass (IRR 1.08; 95% CI: [1.02, 1.15]) and Nissen fundoplication (IRR 1.17; 95% CI [1.09, 1.26]) increased in Medicaid patients treated in expansion states than in those treated in non-expansion states. Simultaneously, the costs reported for self-pay patients increased in expansion states more than in non-expansion states (+$1669; 95% CI [$655, $2682]). Conclusions: Medicaid expansion was associated with increased rates of utilization of MIS approaches to several surgical procedures and a shifting of costs toward patients who were self-insured. Keywords: Affordable care act medicaid expansion; Healthcare disparities; Minimally invasive surgery; Public health policy.

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Does the Halo Effect for Level 1 Trauma Centers Apply to High-Acuity Nonsurgical Admissions?

Ann E Hwalek, Anai N Kothari, Elizabeth H Wood, Barbara A Blanco, McKenzie Brown, Timothy P Plackett, Paul C Kuo, Joseph Posluszny Jr

Context: The halo effect describes the improved surgical outcomes at trauma centers for nontrauma conditions. Objective: To determine whether level 1 trauma centers have improved inpatient mortality for common but high-acuity nonsurgical diagnoses (eg, acute myocardial infarction [AMI], congestive heart failure [CHF], and pneumonia [PNA]) compared with non--level 1 trauma centers. Methods: The authors conducted a population-based, retrospective cohort study analyzing data from the Healthcare Cost and Utilization Project State Inpatient Database and the American Hospital Association Annual Survey Database. Patients who were admitted with AMI, CHF, and PNA between 2006-2011 in Florida and California were included. Level 1 trauma centers were matched to non-level 1 trauma centers using propensity scoring. The primary outcome was risk-adjusted inpatient mortality for each diagnosis (AMI, CHF, or PNA). Results: Of the 190,474 patients who were hospitalized for AMI, CHF, or PNA, 94,037 patients (49%) underwent treatment at level 1 trauma centers. The inpatient mortality rates at level 1 trauma centers vs non-level 1 trauma centers for patients with AMI was 8.10% vs 8.40%, respectively (P=.73); for patients with CHF, 2.26% vs 2.71% (P=.90); and for patients with PNA, 2.30% vs 2.70% (P=.25). Conclusion: Level 1 trauma center designation was not associated with improved mortality for high-acuity, nonsurgical medical conditions in this study.

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Robotic Approach to Outpatient Inguinal Hernia Repair

Haroon Janjua, Evelena Cousin-Peterson, Tara M Barry, Marissa C Kuo, Marshall S Baker, Paul C Kuo

Background: Robotics offers improved ergonomics, visualization, instrument articulation, and tremor filtration. Disadvantages include startup cost and system breakdown. Surgeon education notwithstanding, we hypothesize that robotic inguinal hernia repair carries minimal advantages over the laparoscopic or open approach. Methods: The 2009-2015 Healthcare Cost and Utilization Project-State Ambulatory Surgery and Services and American Hospital Association Annual Health data sets from Florida were queried for open, laparoscopic, and robotic inguinal hernia repairs. Hospital and patient demographic, financial, and comorbidity data (26 total variables) were evaluated. Data are presented as mean ± SEM; p < 0.05 was considered significant. Results: We identified 103,183 cases (63,375 open, 38,886 laparoscopic, and 922 robotic). Patient characteristics were the following: male, white, aged 51 to 70 years, nongovernmental and not-for-profit hospitals, grouped Charlson Comorbidity Category = 0, private insurance coverage, median income quartile 3 (4 = highest), and routine discharge disposition (all, p < 0.05). Total charges were: $18,261 ± $38 (open), $25,223 ± $60 (laparoscopic), and $45,830 ± $1,023 (robot) (p < 0.0001 robot vs open, robot vs laparoscopic, and laparoscopic vs open). Top factors associated with open procedures (area under the curve 0.785): hospital is investor owned for profit, self-pay, black, Latino, and Medicaid; with laparoscopic procedures (area under the curve 0.771): private insurance, median income quartile 4 (highest), median income quartile 3, median income quartile 2, and nongovernmental, not-for-profit hospitals; and with robotic procedures (area under the curve 0.936): Charlson Comorbidity Category = 2, Charlson Comorbidity Category = 1, median income quartile 3, median income quartile 2, and age. Conclusions: Robotic surgery has increased charges and is performed in sicker, higher-income patients. The open approach is more apt to be performed in black/Hispanic, self-pay patients, and for-profit hospitals. The role for robotic inguinal hernia repair is undefined.

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The paradox of the robotic approach to inguinal hernia repair in the inpatient setting

Haroon Janjua, Evelena Cousin-Peterson, Tara M Barry, Marissa C Kuo, Marshall S Baker, Paul C Kuo

Background: Robotics offers improved ergonomics, enhanced visualization, and increased dexterity. Disadvantages include startup, maintenance and instrument costs. Surgeon education notwithstanding, we hypothesized that robotic inguinal hernia repair carries minimal advantages over the open or laparoscopic approach in the inpatient setting. Methods: The HCUP-SID and AHA datasets were queried for inguinal hernia repair codes. Hospital and patient demographic, financial and comorbidity data were evaluated. Data are presented as mean ± SEM. Results: 36396 cases (27776 Open, 7104 Laparoscopic and 1516 Robotic) were identified. Total costs were: $13595 ± 104 (Open), $13581 ± 176 (Laparoscopic) and $18494 ± 323 (Robotic). (p < 0.0001 Robotic vs Open, Robotic vs Laparoscopic) Robotic costs were 38% greater than that of the Open and Laparoscopic subsets (p < 0.001 Robotic vs. Open and Laparoscopic). The Open, Laparoscopic and Robotic subsets' length of stay were 4.2, 3.2 and 2.3 days, respectively. (p < 0.0001 among Open, Laparoscopic and Robotic). Conclusion: The Robotic approach to the inguinal hernia repair had the lowest length of stay, despite having the highest costs. The benefits of robotic surgery in inguinal hernia repair are unclear in the inpatient setting. Keywords: Inguinal hernia; Inpatient; Laparoscopic; Open; Robotic

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Weekend readmissions associated with mortality following pancreatic resection for cancer

Anai N Kothari, Linda T Qu , Lindsey A Gil, Bianca di Chiaro, Patrick J Sweigert, Sujay Kulshrestha, Paul C Kuo, Gerard J Abood

Background: The weekend effect is associated with an increased risk of adverse events, with complex patient populations especially susceptible to its impact. The objective of this study was to determine if outcomes for patients readmitted following pancreas resection differed on the weekend compared to weekdays. Methods: The Healthcare Cost and Utilization State Inpatient Database for Florida was used to identify patients undergoing pancreas resection for cancer who were readmitted within 30 days of discharge following surgery. Measured outcomes (for readmission encounters) included inpatient morbidity and mortality. Results: Patients with weekend readmissions had an increased odds of inpatient mortality (aOR 2.7, 95% C.I.: 1.1-6.6) compared to those with weekday readmissions despite having similar index lengths of stay (15.9 vs. 15.5 days, P = .73), incidence of postoperative inpatient complications (22.4% vs. 22.3%, P = .98), reasons for readmission, and baseline comorbidity. Discussion: Weekend readmissions following pancreatic resection are associated with increased risk of mortality. This is not explained by measured patient factors or clinical characteristics of the index hospital stay. Developing strategies to overcome the weekend effect can result in improved care for patients readmitted on the weekend. Keywords: Pancreas cancer; Readmissions; Weekend effect

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Does resection improve overall survival for intrahepatic cholangiocarcinoma with nodal metastases?

Patrick J Sweigert, Emanuel Eguia, Haroon Janjua, Sean P Nassoiy, Lawrence M Knab, Gerard Abood, Paul C Kuo, Marshall S Baker

Background: The potential benefit of surgical resection of intrahepatic cholangiocarcinoma in patients with locoregionally advanced disease has not been definitively determined. Methods: The National Cancer Database was queried to identify patients with clinical evidence of node-positive intrahepatic cholangiocarcinoma. Resected patients were stratified by margin status and lymph node ratio (nodes positive to nodes harvested). Risk of death was determined using Cox regression models and Kaplan-Meier survival functions. Results: A total of 1,425 patients with T(any)N1M0 intrahepatic cholangiocarcinoma were identified. Two hundred twelve (14.9%) underwent surgical resection. On multivariable Cox regression, R0 resection afforded a survival benefit regardless of lymph node ratio (lymph node ratio > 0.5: hazard ratio 0.466, 95% confidence interval 0.304-0.715; lymph node ratio ≤ 0.5: hazard ratio 0.444, 95% confidence interval 0.322-0.611), whereas a survival benefit was only seen in R1 patients with lymph node ratio ≤ 0.5 (hazard ratio 0.470, 95% confidence interval 0.316-0.701). On Kaplan-Meier, median survival was 11.6 months with chemotherapy, 15.7 months with R0 resection in lymph node ratio > 0.5, and 22.2 months with R0 resection in lymph node ratio ≤ 0.5 (P < .001). Discussion: Margin negative resection is associated with a risk-adjusted survival benefit for patients with clinically N1 intrahepatic cholangiocarcinoma regardless of the degree of regional lymph node involvement.

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Predictors of Death in Necrotizing Skin and Soft Tissue Infection

Emanuel Eguia, Vincent Vivirito, Adrienne N Cobb, Haroon Janjua, Matthew Cheung, Paul C Kuo

Background: Necrotizing skin and soft tissue infection (NSTI) is a surgical emergency that is associated with high morbidity and mortality. This study aims to identify predictors of in-hospital death following a NSTI. Material and methods: We queried the Healthcare Cost and Utilization Project (HCUP) State Inpatient Database (SID) for California between 2006 and 2011. We used conventional and advanced statistical methods to identify predictors of in-hospital mortality, which included: logistic regression, stepwise logistic regression, decision trees, and K-nearest neighbor (KNN) algorithms. Results: A total of 10,158 patients had a NSTI. The full and stepwise logistic regression models had a ROC AUC in the validation dataset of 0.83 (95% CI [0.80, 0.86]) and 0.81 (95% CI [0.78, 0.83]), respectively. The KNN and decision tree model had a ROC AUC of 0.84 (95% CI [0.81, 0.85]) and 0.69 (95% CI [0.65, 0.72]), respectively. The top predictors of in-hospital mortality in the KNN and stepwise logistic model included: (1) the presence of in-hospital coagulopathy, (2) having an infectious or parasitic diagnoses, (3) electrolyte disturbances, (4) advanced age, and (5) the total number of beds in a hospital. Conclusion: Patients with a NSTI have high rates of in-hospital mortality. This study highlights the important factors in managing patients with a NSTI which include: correcting coagulopathy and electrolyte imbalances, treating underlying infectious processes, providing adequate resources to the elderly population, and managing patients in high-volume centers.

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The laparoscopic approach to distal pancreatectomy is a value-added proposition for patients undergoing care in moderate-volume and high-volume centers

Emanuel Eguia, Paul C Kuo, Patrick Sweigert, Marc Nelson, Gerard V Aranha, Gerard Abood, Constantine V Godellas, Marshall S Baker

Background: Little is known regarding the impact of the minimally invasive approach to distal pancreatectomy on the aggregate costs of care for patients undergoing distal pancreatectomy. Methods: We queried the Healthcare Cost and Utilization Project State Inpatient Database to identify patients undergoing elective laparoscopic distal pancreatectomy or open distal pancreatectomy between 2012 and 2014. Multivariable regression was used to evaluate postoperative outcomes including readmissions to 90 days after distal pancreatectomy. Results: A total of 267 (11%) patients underwent laparoscopic distal pancreatectomy, and a total of 2,214 (89%) underwent open distal pancreatectomy. On multivariable regression, patients undergoing laparoscopic distal pancreatectomy had a decreased odds risk of having any severe adverse outcome (odds ratio 0.73, 95% confidence interval [0.54-0.97]), prolonged length of stay (odds ratio 0.49, 95% confidence interval [0.30-0.79]), and of being in the highest quartile for aggregate costs of care (odds ratio 0.46, 95% confidence interval [0.32-0.66]) relative to those undergoing open distal pancreatectomy. Patients undergoing laparoscopic distal pancreatectomy had a lower average 90-day aggregate cost of care than those undergoing open distal pancreatectomy when procedures were performed in high-volume (-$16,153, 95% CI: [-$23,342 to -$8,964]) centers. Conclusion: Patients undergoing laparoscopic distal pancreatectomy have a lower risk of severe adverse outcomes, prolonged overall length of stay, and lower associated costs of care relative to those undergoing open distal pancreatectomy. This association is independent of hospital volume

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The laparoscopic approach to pancreatoduodenectomy is cost neutral in very high-volume centers

Emanuel Eguia, Paul C Kuo, Patrick J Sweigert, Marc H Nelson, Gerard V Aranha, Gerard Abood, Constantine Godellas, Marshall S Baker

Background: Little is known regarding the impact of minimally invasive approaches to pancreatoduodenectomy on the aggregate costs of care for patients undergoing pancreatoduodenectomy. Methods: We queried the Healthcare Cost and Utilization Project State Inpatient Database to identify patients undergoing elective laparoscopic or open pancreatoduodenectomy between 2014 and 2016. Results: In this database, 488 (10%) patients underwent elective laparoscopic; 4,544 (90%) underwent open pancreatoduodenectomy. On adjusted analysis, the risk of perioperative morbidity and overall duration of hospitalization for patients undergoing elective laparoscopic were identical to those for patients undergoing open pancreatoduodenectomy. Patients undergoing elective laparoscopic in low (+$10,399, 95% confidence interval [$3,700, $17,098]) and moderate to high (+$4,505, 95% confidence interval [$528, $8,481]) volume centers had greater costs than those undergoing open pancreatoduodenectomy in the same centers. In very high-volume centers (>127 pancreatoduodenectomies/year), aggregate costs of care for patients undergoing elective laparoscopic were essentially identical to those undergoing open pancreatoduodenectomy in the same centers (+$815, 95% confidence interval [-$1,530, $3,160]). Conclusion: Rates of morbidity and overall duration of hospitalization for patients undergoing elective laparoscopic are not different than those undergoing open pancreatoduodenectomy. At low to moderate and high-volume centers, elective laparoscopic is associated with greater aggregate costs of care relative to open pancreatoduodenectomy. At very high-volume centers, elective laparoscopic is cost-neutral.

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New docs on the block: A profile of applicants and subsequent PGY1 trainees of categorical general surgery programs (2013-2016)

Adrienne N Cobb, Marissa C Kuo, Paul C Kuo

Background: The categorical general surgery (GS) applicant pool and trainees have evolved. The purpose of this study is to profile contemporary applicants and subsequent matriculates of GS residencies. Study design: This study is a retrospective review of GS applicant and PGY1 trainee data which were obtained from ERAS, NRMP, and AAMC for the years 2013-2016. Univariate statistics were used to compare matched GS trainees other trainees in other specialties. Results: In 2016 GS was among the top 5 most competitive residencies as measured by mean applications/applicant. In 2013, 2415 applicants applied for 1185 spots resulting in 99.6% fill. The 2014 PGY1 class exhibited: mean Step 1232 vs. 213 and Step 2245 vs. 226 when comparing matched to unmatched. The mean number of abstracts/publications and %AOA were 4.4 v. 2.7, and 4.4% vs.2.7% respectively. Surgical subspecialty trainees had significantly higher Step 1 and 2 scores, publications, and %AOA (p < .0001). Conclusion: General surgery is an increasingly competitive specialty. PGY1 trainees compare well with their CIM and Obstetrics peers, but lag behind their surgical subspecialty colleagues. Keywords: General surgery residency; National resident matching program; Surgical education; Surgical trainees; Surgical training.

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Complications of Recognized and Unrecognized Iatrogenic Ureteral Injury at Time of Hysterectomy: A Population Based Analysis

Robert H Blackwell, Eric J Kirshenbaum, Arpeet S Shah, Paul C Kuo, Gopal N Gupta, Thomas M T Turk

Purpose: Ureteral injury represents an uncommon but potentially morbid surgical complication. We sought to characterize the complications of iatrogenic ureteral injury and assess the effect of recognized vs delayed recognition on patient outcomes. Materials and methods: Patients who underwent hysterectomy were identified in the Healthcare Cost and Utilization Project California State Inpatient Database for 2007 to 2011. Ureteral injuries were identified and categorized as recognized-diagnosed/repaired on the day of hysterectomy and unrecognized-diagnosed/repaired postoperatively. We assessed the outcomes of 90-day hospital readmission as well as 1-year outcomes of nephrostomy tube placement, urinary fistula, acute renal failure, sepsis and overall mortality. The independent effects of recognized and unrecognized ureteral injuries were determined on multivariate analysis. Results: Ureteral injury occurred in 1,753 of 223,872 patients (0.78%) treated with hysterectomy and it was unrecognized in 1,094 (62.4%). The 90-day readmission rate increased from a baseline of 5.7% to 13.4% and 67.3% after recognized and unrecognized injury, respectively. Nephrostomy tubes were required in 2.3% of recognized and 23.4% of unrecognized ureteral injury cases. Recognized and unrecognized ureteral injuries independently increased the risk of sepsis (aOR 2.0, 95% CI 1.2-3.5 and 11.9, 95% CI 9.9-14.3) and urinary fistula (aOR 5.9, 95% CI 2.2-16 and 124, 95% CI 95.7-160, respectively). During follow up unrecognized ureteral injury increased the odds of acute renal insufficiency (aOR 23.8, 95% CI 20.1-28.2) and death (1.4, 95% CI 1.03-1.9, p = 0032). Conclusions: Iatrogenic ureteral injury increases the risk of hospital readmission and significant, potentially life threatening complications. Unrecognized ureteral injury markedly increases these risks, warranting a high level of suspicion for ureteral injury and a low threshold for diagnostic investigation. Keywords: hysterectomy; iatrogenic disease; injuries; intraoperative complications; ureter

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Adhesive Bowel Obstruction Following Urologic Surgery: Improved Outcomes with Early Intervention

Robert H Blackwell, Anai N Kothari, Arpeet Shah, William Gange , Marcus L Quek , Fred A Luchette, Robert C Flanigan, Paul C Kuo, Gopal N Gupta 

Objective: To describe the long-term incidence of adhesive bowel obstruction following major urologic surgery, and the effect of early surgery on perioperative outcomes. Methods: The Healthcare Cost and Utilization Project State Inpatient Databases for California and Florida (2006-2011) were used to identify major urologic oncologic surgery patients. Subsequent adhesive bowel obstruction admissions were identified and Kaplan-Meier time-to-event analysis was performed. Early surgery for bowel obstruction was defined as occurring on-or-before hospital-day four. The effects of early surgery on postoperative minor/moderate complications (wound infection, urinary tract infection, deep vein thrombosis, and pneumonia), major complications (myocardial infarction, pulmonary embolism, and sepsis), death, and postoperative length-of-stay were assessed. Results: Major urologic surgery was performed on 104,400 patients, with subsequent 5-year cumulative incidence of adhesive bowel obstruction admission of 12.4% following radical cystectomy, 3.3% following kidney surgery, and 0.9% following prostatectomy. During adhesive bowel obstruction admission, 71.6% of patients were managed conservatively and 28.4% surgically. Early surgery was performed in 65.4%, with decreased rates of minor/moderate complications (18 vs. 30%, p = 0.001), major complications (10 vs. 19%, p = 0.002), and median postoperative length of stay (8 vs. 11 days, p < 0.001) compared with delayed surgery. On multivariate analysis early surgery decreased the odds of minor/ moderate complications by 43% (p = 0.01), major complications by 45% (p = 0.03), and postoperative length of stay by 3.1 days (p = 0.01). Conclusion: Adhesive bowel obstruction is a significant long-term sequela of urologic surgery, for which early surgical management may be associated with improved perioperative outcomes. Keywords: Cystectomy; Intestinal obstruction; Longitudinal studies; Nephrectomy; Prostatectomy

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Predicting burn patient mortality with electronic medical records

Matthew Cheung, Adrienne N Cobb, Paul C Kuo

Background: Although there exists robust literature on mortality-associated factors in burn patients, it is not known how electronic medical records affect outcomes. Using burn injury as a surgical care model of information and communication, we hypothesized that functionality and interoperability of the electronic medical record could serve as determinants of outcome. Methods: We used the state inpatient databases for New York, Washington, California, and Florida for the years 2009 and 2010 for all states, with the additional years of 2012 and 2013 for New York (n = 6,002), and the respective data from the American Hospital Association Information Technology survey. Using International Classification of Diseases, Ninth Revision, codes, we included burn patients and characterized total body surface area burned. We summed the binary answers to questions 1 and 2 and question 3 from the American Hospital Association Information Technology survey to make continuous functionality and interoperability scores. Mortality was predicted using extreme gradient boosting in Python. Results: In each state in which our models had an accuracy and area under the curve of more than 0.90, electronic medical record functionality but not interoperability was a significant predictor in New York, California, and Florida. Important predictors in each state were, age, duration of stay, total body surface area burned/severity, and total charges. Electronic medical record functionality was more important than all comorbidities except for coagulopathies and electrolyte disorders. Higher functionality scores were associated with mortality (P < .01). Conclusion: Our data support our hypothesis that electronic medical records may be associated with mortality in burn patients; however, electronic medical records are not having the intended impact on outcomes, and further research needs to elucidate exactly how electronic medical records are being used in clinical settings.

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Metabolic Syndrome Increases Risk of Postoperative Myocardial Infarction Following Percutaneous Nephrolithotomy

Johans C, Bajic P, Kirshenbaum E, Blackwell RH, Kothari AN, Kuo P, Baldea K, Turk T

Introduction: Percutaneous nephrolithotomy (PCNL) is the gold standard treatment for upper tract stone burdens greater than 2cm. Metabolic syndrome (MetS) is a constellation of conditions (diabetes mellitus, hypertension, dyslipidemia, and obesity) and is a risk factor for nephrolithiasis. Our objective was to investigate adverse cardiovascular outcomes of PCNL in patients with comorbid MetS diagnoses. Methods: Data from the Healthcare Cost and Utilization Project State Inpatient Database for Florida and California were used to identify PCNL patients (ICD9: 55.03, 55.04) between 2007 and 2011. Patients were categorized having zero, 1-2, or 3-4 components of MetS. Postoperative myocardial infarction (MI) and in-hospital mortality outcomes were identified. Multivariate logistic regression was used to control for patient characteristics (age race, primary insurance provider) and medical comorbidities. Results: PCNL was performed on 39,868 patients, of whom 17,932 (45.0%) had no MetS conditions, 19,268 (48.3%) had 1-2 MetS conditions, and 2,668 (6.7%) had 3-4 MetS conditions. With increasing MetS conditions, patients had increased incidence of postoperative MI (zero: 0.6%; 1-2: 1.0%; 3-4: 1.8%, p<0.001). On multivariate analysis, the presence of 3-4 MetS comorbidities increased the odds of a postoperative MI (1-2: OR 1.2, 95% CI 0.94-1.53, p=0.147; 3-4: OR 2.2, 95%CI 1.54-3.15, p<0.001). Conclusion: MetS patients have an increased risk of MI following PCNL given their preexisting comorbidities. Routine preoperative cardiac testing may benefit this population prior PCNL.

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Big data: More than big data sets

Cobb AN, Benjamin AJ, Huang ES, Kuo PC

The term big data has been popularized over the past decade and is often used to refer to data sets that are too large or complex to be analyzed by traditional means. Although the term has been utilized for some time in business and engineering, the concept of big data is relatively new to medicine. The reception from the medical community has been mixed; however, the widespread utilization of electronic health records in the United States, the creation of large clinical data sets and national registries that capture information on numerous vectors affecting healthcare delivery and patient outcomes, and the sequencing of the human genome are all opportunities to leverage big data. This review was inspired by a lively panel discussion on big data that took place at the 75th Central Surgical Association Annual Meeting. The authors' aim was to describe big data, the methodologies used to analyze big data, and their practical clinical application.

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Put Me in the Game Coach! Resident Participation in High-risk Surgery in the Era of Big Data

Adrienne N Cobb, Emanuel Eguia , Haroon Janjua, Paul C Kuo

Background: With the emphasis on quality metrics guiding reimbursement, concerns have emerged regarding resident participation in patient care. This study aimed to evaluate whether resident participation in high-risk elective general surgery procedures is safe. Materials and methods: The American College of Surgeons National Surgical Quality Improvement Program database (2005-2012) was used to identify patients undergoing one of five high-risk general surgery procedures. Resident and nonresident groups were created using a 2:1 propensity score match. Postoperative outcomes were calculated using univariate statistics and multivariable logistic regression for the two groups. Predictors of mortality and morbidity were identified using machine learning in the form of decision trees. Results: Twenty-five thousand three hundred sixty three patients met our inclusion criteria. Following matching, each group contained 500 patients and was comparable for matched characteristics. Thirty-day mortality was similar between the groups (2.4% versus 2.6%; P = 0.839). Deep surgical site infection (0% versus 1.6%; P = 0.005), urinary tract infection (5% versus 2.5%; P = 0.029), and operative time (275.6 min versus 250 min; P = 0.0064) were significantly higher with resident participation. Resident participation was not predictive of mortality or complications, while age, American society of anesthesiologists class, and functional status were leading predictors of both. Conclusions: Despite growing time constraints and pressure to perform, surgical resident participation remains safe. Residents should be given active roles in the operating room, even in the most challenging cases.

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Racial and Ethnic Postoperative Outcomes After Surgery: The Hispanic Paradox

Emanuel Eguia, Adrienne N Cobb, Eric J Kirshenbaum, Majid Afshar, Paul C Kuo

Background: The Hispanic population in the United States have previously been shown to have, in some cases, better health outcomes than non-Hispanic whites (NHWs) despite having lower socioeconomic status and higher frequency of comorbidities. This epidemiologic finding is coined as the Hispanic Paradox (HP). Few studies have evaluated if the HP exists in surgical patients. Our study aimed to examine postoperative complications between Hispanic and NHW patients undergoing low- to high-risk procedures. Materials and methods: We conducted a retrospective cohort study analyzing adult patients who underwent high-, intermediate-, and low-risk procedures. The Healthcare Cost and Utilization Project California State Inpatient Database between 2006 and 2011 was used to identify the patient cohort. Candidate variables for the adjusted model were determined a priori and included patient demographics with the ethnic group as the exposure of interest. Results: The median age for Hispanics was 52 (SD 19.3) y, and 38.8% were male (n = 87,837). A higher proportion of Hispanics had Medicaid insurance (23.9% versus 3.8%) or were self-pay (14.2% versus 4.5%) compared with NHWs. In adjusted analysis, Hispanics had a higher odds risk for postoperative complications across all risk categories combined (OR 1.06, 95% CI 1.04-1.09). They also had an increased in-hospital (OR 1.38, 95% CI 1.14-1.30) and 30-d mortality in high-risk procedures (OR 1.34, 95% CI 1.19-1.51). Conclusions: Hispanics undergoing low- to high-risk surgery have worse outcomes compared with NHWs. These results do not support the hypothesis of an HP in surgical outcomes. Keywords: Health care disparities; Hispanic outcomes; Hispanic paradox; Social determinants of health.

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Epidemiology, treatment, and outcomes of acute limb ischemia in the pediatric population

Sungho Lim, Michael J Javorski, Pegge M Halandras, Paul C Kuo, Bernadette Aulivola, Paul Crisostomo

Objective: Acute limb ischemia (ALI) in a pediatric patient is a rare condition but may result in lifelong disability. A paucity of evidence exists to derive treatment guidelines; some surgeons advocate conservative management over invasive measures. The purpose of this study was to evaluate the role of surgical revascularization in the pediatric population and outcomes of conservative vs surgical management. Methods: The Healthcare Cost and Utilization Project State Inpatient Database (California, Iowa, and New York) between 2007 and 2013 was queried using International Classification of Diseases, Ninth Revision codes. Patients were stratified into two cohorts: conservative management and surgical management. Each group was further subdivided into three age groups: infant (<24 months), child (<12 years), and adolescent (<18 years). Outcome variables included mortality, amputation status, length of hospital stay, and hospital charge. Results: A total of 1576 pediatric patients with ALI were identified among 6,122,535 pediatric admissions (26 per 100,000 admissions). Average age was 9.9 ± 7.1 years. There were 263 patients who underwent surgical revascularization. The conservative management group was younger (5.8 ± 6.2 vs 9.2 ± 6.1 years; P < .01). Otherwise, baseline characteristics were similar between the two groups. Overall, the amputation rate was low (<2%; n = 28), especially in the upper extremities (<0.2%). Outcomes of conservative management and surgical revascularization were similar for mortality (5.0% vs 3.4%; P = .34), amputation (1.9% vs 1.1%; P = .46), length of hospital stay (15.4 vs 12.9 days; P = .07), and hospital charge ($281,794 vs $288,507; P = .28). In subgroup analysis, infants had less concomitant orthopedic injury than other age groups. Children demonstrated a higher likelihood of associated upper extremity injury and operative revascularization (P < .01) than infants or adolescents. In infants, mortality was higher and surgical intervention was associated with longer hospital stay (29.5 ± 34.4 days vs 45.6 ± 31.6 days; P = .02) and larger health care expenditure ($467,885 ± $638,653 vs $1,099,343 ± $695,872; P < .01). Conclusions: Pediatric ALI is a rare entity and is associated with low amputation and mortality rates. Among the pediatric age cohorts, infants with ALI are at higher risk of in-hospital mortality than older age groups are. Surgical intervention is not associated with improved limb salvage or mortality. Nonoperative management may be considered an initial treatment modality, but further research is needed to elucidate which important subset of pediatric patients benefit from open or endovascular operative intervention.

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The LACE Score as a Tool to Identify Radical Cystectomy Patients at Increased Risk of 90-Day Readmission and Mortality

Jennifer L Saluk, Robert H Blackwell, William S Gange, Matthew A C Zapf, Anai N Kothari, Paul C Kuo, Marcus L Quek, Robert C Flanigan, Gopal N Gupta

Introduction: Radical cystectomy for bladder cancer is associated with high rates of readmission. We investigated the LACE score, a validated prediction tool for readmission and mortality, in the radical cystectomy population. Materials & methods: Patients who underwent radical cystectomy for bladder cancer were identified by ICD-9 codes from the Healthcare Cost and Utilization Project State Inpatient Database for California years 2007-2010. The LACE score was calculated as previously described, with components of L: length of stay, A: acuity of admission, C: comorbidity, and E: number of emergency department visits within 6 months preceding surgery. Results: Of 3,470 radical cystectomy patients, 638 (18.4%) experienced 90-day readmission, and 160 (4.6%) 90-day mortality. At a previously validated "high-risk" LACE score ≥ 10, patients experienced an increased risk of 90-day readmission (22.8 vs. 17.7%, p = 0.002) and mortality (9.1 vs. 3.5%, p < 0.001). On adjusted multivariable analysis, "high risk" patients by LACE score had increased 90-day odds of readmission (adjusted OR = 1.24, 95% CI: 0.99-1.54, p = 0.050) and mortality (adjusted OR = 2.09, 95% CI: 1.47-2.99, p < 0.001). Conclusion: The LACE score reasonably identifies patients at risk for 90-day mortality following radical cystectomy, but only poorly predicts readmission. Providers may use the LACE score to target high-risk patients for closer follow-up or intervention. Keywords: Cystectomy; Outcomes assessment; Urologic surgical procedures

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Impact of the Affordable Care Act (ACA) Medicaid Expansion on Cancer Admissions and Surgeries

Eguia E, Cobb AN, Kothari AN, Molefe A, Afshar M, Aranha GV, Kuo PC

Objective: This study aims to evaluate the trends in cancer (CA) admissions and surgeries after the Affordable Care Act (ACA) Medicaid expansion. Methods: This is a retrospective study using HCUP-SID analyzing inpatient CA (pancreas, esophagus, lung, bladder, breast, colorectal, prostate, and gastric) admissions and surgeries pre- (2010-2013) and post- (2014) Medicaid expansion. Surgery was defined as observed resection rate per 100 cancer admissions. Nonexpansion (FL) and expansion states (IA, MD, and NY) were compared. A generalized linear model with a Poisson distribution and logistic regression was used with incidence rate ratios (IRR) and difference-in-differences (DID). Results: There were 317, 858 patients in our sample which included those with private insurance, Medicaid, or no insurance. Pancreas, breast, colorectal, prostate, and gastric CA admissions significantly increased in expansion states but decreased in nonexpansion states. (IRR 1.12, 1.14, 1.11, 1.34, 1.23; P < .05) Lung and colorectal CA surgeries (IRR 1.30, 1.25; P < .05) increased, while breast CA surgeries (IRR 1.25; P < .05) decreased less in expansion states. Government subsidized, or self-pay patients had greater odds of undergoing lung, bladder, and colorectal CA surgery (OR 0.45 vs 0.33; 0.60 vs 0.48; 0.47 vs 0.39; P < .05) in expansion states after reform. Conclusions: In states that expanded Medicaid coverage under the ACA, the rate of surgeries for colorectal and lung CA increased significantly, while breast CA surgeries decreased less. Parenthetically, these cancers are subject to population screening programs. We conclude that expanding insurance coverage results in enhanced access to cancer surgery.

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Adhesive Bowel Obstruction Following Urologic Surgery: Improved Outcomes with Early Intervention

Blackwell RH, Kothari AN, Shah A, Gang W, Quek ML, Luchette FA, Flanigan RC, Kuo PC, Gupta GN

Objective: To describe the long-term incidence of adhesive bowel obstruction following major urologic surgery, and the effect of early surgery on perioperative outcomes. Methods: The Healthcare Cost and Utilization Project State Inpatient Databases for California and Florida (2006-2011) were used to identify major urologic oncologic surgery patients. Subsequent adhesive bowel obstruction admissions were identified and Kaplan-Meier time-to-event analysis was performed. Early surgery for bowel obstruction was defined as occurring on-or-before hospital-day four. The effects of early surgery on postoperative minor/moderate complications (wound infection, urinary tract infection, deep vein thrombosis, and pneumonia), major complications (myocardial infarction, pulmonary embolism, and sepsis), death, and postoperative length-of-stay were assessed. Results: Major urologic surgery was performed on 104,400 patients, with subsequent 5-year cumulative incidence of adhesive bowel obstruction admission of 12.4% following radical cystectomy, 3.3% following kidney surgery, and 0.9% following prostatectomy. During adhesive bowel obstruction admission, 71.6% of patients were managed conservatively and 28.4% surgically. Early surgery was performed in 65.4%, with decreased rates of minor/moderate complications (18 vs. 30%, p = 0.001), major complications (10 vs. 19%, p = 0.002), and median postoperative length of stay (8 vs. 11 days, p < 0.001) compared with delayed surgery. On multivariate analysis early surgery decreased the odds of minor/ moderate complications by 43% (p = 0.01), major complications by 45% (p = 0.03), and postoperative length of stay by 3.1 days (p = 0.01). Conclusion: Adhesive bowel obstruction is a significant long-term sequela of urologic surgery, for which early surgical management may be associated with improved perioperative outcomes. Keywords: Cystectomy; Intestinal obstruction; Longitudinal studies; Nephrectomy; Prostatectomy

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Commercial quality "awards" are not a strong indicator of quality surgical care

Cobb AN, Erickson TR, Kothari AN, Eguia E, Brownlee SA, Yao W, Choi H, Greenberg V, Mboya J, Voss M, Raicu DS, Settimi-Woods R, Kuo PC

Objective:This study aimed to determine whether publicized hospital rankings can be used to predict surgical outcomes. Methods: Patients undergoing one of nine surgical procedures were identified, using the Healthcare Cost and Utilization Project State Inpatient Database for Florida and New York 2011-2013 and merged with hospital data from the American Hospital Association Annual Survey. Nine quality designations were analyzed as possible predictors of inpatient mortality and postoperative complications, using logistic regression, decision trees, and support vector machines. Results: We identified 229,657 patients within 177 hospitals. Decision trees were the highest performing machine learning algorithm for predicting inpatient mortality and postoperative complications (accuracy 0.83, P<.001). The top 3 variables associated with low surgical mortality (relative impact) were Hospital Compare (42), total procedure volume (16) and, Joint Commission (12). When analyzed separately for each individual procedure, hospital quality awards were not predictors of postoperative complications for 7 of the 9 studied procedures. However, when grouping together procedures with a volume-outcome relationship, hospital ranking becomes a significant predictor of postoperative complications. Conclusion: Hospital quality rankings are not a reliable indicator of quality for all surgical procedures. Hospital and provider quality must be evaluated with an emphasis on creating consistent, reliable, and accurate measures of quality that translate to improved patient outcomes.

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Alcohol enhances symptoms and propensity for infection in inflammatory bowel disease patients and a murine model of DSS-induced colitis

Cannon AR, Kuprys PV, Cobb AN, Ding X, Kothari AN, Kuo PC, Eberhardt JM, Hammer AM, Morris NL, Li X, Choudhry MA

Over 1.4 million Americans have been diagnosed with inflammatory bowel disease (IBD), and ulcerative colitis (UC) makes up approximately half of those diagnoses. As a disease, UC cycles between periods of remission and flare, which is characterized by intense abdominal pain, increased weight loss, intestinal inflammation, rectal bleeding, and dehydration. Interestingly, a widespread recommendation to IBD patients for avoidance of a flare period is "Don't Drink Alcohol" as recent work correlated alcohol consumption with increased GI symptoms in patients with IBD. Alcohol alone not only induces a systemic pro-inflammatory response, but can also be directly harmful to gut barrier integrity. However, how alcohol could result in the exacerbation of UC in both patients and murine models of colitis has yet to be elucidated. Therefore, we conducted a retrospective analysis of patients admitted for IBD with a documented history of alcohol use in conjunction with a newly developed mouse model of binge alcohol consumption following dextran sulfate sodium (DSS)-induced colitis. We found that alcohol negatively impacts clinical outcomes of patients with IBD, specifically increased intestinal infections, antibiotic injections, abdomen CT scans, and large intestine biopsies. Furthermore, in our mouse model of binge alcohol consumption following an induced colitis flare, we found alcohol exacerbates weight loss, clinical scores, colonic shortening and inflammation, and propensity to infection. These findings highlight alcohol's ability to potentiate symptoms and susceptibility to infection in UC and suggest alcohol as an underlying factor in perpetuating symptoms of IBD.

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Implications of postoperative pulmonary aspiration following major urologic surgery

Kirshenbaum EJ, Blackwell RH, Li B, Kothari AN, Kuo PC, Flanigan RC, Gorbonos A, Gupta GN.

Introduction: The purpose of this article is to assess the incidence of pulmonary aspiration following major urologic surgery, predictors of an aspiration event, and subsequent clinical outcomes. Material and Methods: The Healthcare Cost and Utilization Project State Inpatient Database for California between 2007-2011 was used to identify cystectomy, prostatectomy, partial and radical nephrectomy patients. Aspiration events were identified within 30 days of surgery. The primary outcome was 30 day mortality and secondary outcomes included total length of stay, discharge location, and diagnoses of acute renal failure, pneumonia or sepsis. Descriptive statistics were performed. A multivariable logistic regression was performed to determine independent predictors of an aspiration event. A separate nonparsimonious logistic regression was fit to determine the independent effect of an aspiration event on 30 day mortality. Results: Of 84,837 major urologic surgery patients 319 (0.4%) had an aspiration event. Risk factors for aspiration included ileus, congestive heart failure, paraplegia, chronic lung disease, and age = 80 years (all p < 0.01). Aspiration patients had higher rates of renal failure (36.1% versus 2.5%), pneumonia (36.1% versus 2.5%), sepsis (35.7% versus 0.7%), a prolonged length of stay (17 days versus 3 days), and discharge to nursing facility(26.3% vs 2.3%) (all p<0.001). The 30 day mortality rate following aspiration was 20.7% compared to 0.8% (p < 0.001). Aspiration independently increases the risk of 30 day mortality (OR 3.1 (95%CI 2.2-4.5). Conclusion: Postoperative aspiration following major urologic surgery is a devastating complication and precautions must be undertaken in high risk patient populations to avoid such an event.

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Complications of Recognized and Unrecognized Iatrogenic Ureteral Injury at Time of Hysterectomy: A Population Based Analysis

Blackwell RH, Kirshenbaum EJ, Shah AS, Kuo PC, Gupta GN, Turk TMT

Purpose: Ureteral injury represents an uncommon but potentially morbid surgical complication. We sought to characterize the complications of iatrogenic ureteral injury and assess the effect of recognized vs delayed recognition on patient outcomes. Materials and Methods: Patients who underwent hysterectomy were identified in the Healthcare Cost and Utilization Project California State Inpatient Database for 2007 to 2011. Ureteral injuries were identified and categorized as recognized-diagnosed/repaired on the day of hysterectomy and unrecognized-diagnosed/repaired postoperatively. We assessed the outcomes of 90-day hospital readmission as well as 1-year outcomes of nephrostomy tube placement, urinary fistula, acute renal failure, sepsis and overall mortality. The independent effects of recognized and unrecognized ureteral injuries were determined on multivariate analysis. Results: Ureteral injury occurred in 1,753 of 223,872 patients (0.78%) treated with hysterectomy and it was unrecognized in 1,094 (62.4%). The 90-day readmission rate increased from a baseline of 5.7% to 13.4% and 67.3% after recognized and unrecognized injury, respectively. Nephrostomy tubes were required in 2.3% of recognized and 23.4% of unrecognized ureteral injury cases. Recognized and unrecognized ureteral injuries independently increased the risk of sepsis (aOR 2.0, 95% CI 1.2-3.5 and 11.9, 95% CI 9.9-14.3) and urinary fistula (aOR 5.9, 95% CI 2.2-16 and 124, 95% CI 95.7-160, respectively). During followup unrecognized ureteral injury increased the odds of acute renal insufficiency (aOR 23.8, 95% CI 20.1-28.2) and death (1.4, 95% CI 1.03-1.9, p = 0032). Conclusions: Iatrogenic ureteral injury increases the risk of hospital readmission and significant, potentially life threatening complications. Unrecognized ureteral injury markedly increases these risks, warranting a high level of suspicion for ureteral injury and a low threshold for diagnostic investigation. Keywords: hysterectomy; iatrogenic disease; injuries; intraoperative complications; ureter

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Seeing the forest beyond the trees: Predicting survival in burn patients with machine learning

Cobb AN, Daungjaiboon W, Brownlee SA, Baldea AJ, Sanford AP, Mosier MM, Kuo PC

Background: This study aims to identify predictors of survival for burn patients at the patient and hospital level using machine learning techniques. Methods: The HCUP SID for California, Florida and New York were used to identify patients admitted with a burn diagnosis and merged with hospital data from the AHA Annual Survey. Random forest and stochastic gradient boosting (SGB) were used to identify predictors of survival at the patient and hospital level from the top performing model. Results: We analyzed 31,350 patients from 670 hospitals. SGB (AUC 0.93) and random forest (AUC 0.82) best identified patient factors such as age and absence of renal failure (p < 0.001) and hospital factors such as full time residents (p < 0.001) and nurses (p = 0.004) to be associated with increased survival. Conclusions: Patient and hospital factors are predictive of survival in burn patients. It is difficult to control patient factors, but hospital factors can inform decisions about where burn patients should be treated.

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Carotid Body Tumor Resection: Just as Safe without Preoperative Embolization

Cobb AN, Barkat A, Daungjaiboon W, Halandras P, Crisostomo P, Kuo PC, Aulivola B

Background: Carotid body tumors (CBTs) are rare entities for which surgical resection remains the gold standard. Given their hypervascularity, preoperative embolization is often used; however, controversy exists over whether a benefit is associated. Proponents of embolization argue that it minimizes blood loss and complications. Critics argue that cost and stroke outweigh benefits. This study aimed to investigate the impact of embolization on outcomes following CBT resection. Methods: Patients undergoing CBT resection were identified using the Healthcare Cost and Utilization Project State Inpatient Database for 5 states between 2006 and 2013. Patients were divided into 2 groups: carotid body tumor resection alone (CBTR) and carotid body tumor resection with preoperative arterial embolization (CBETR). Descriptive statistics were calculated using arithmetic means with standard deviations for continuous variables and proportions for categorical variables. Patients were propensity score matched on the basis of sex, age, race, insurance, and comorbidity prior to analysis. Risk-adjusted odds of mortality, stroke, nerve injury, blood loss, and length of stay (LOS) were calculated using mixed-effects regression models with fixed effects for age, race, sex, and comorbidities. Results: A total of 547 patients were identified. Of these, 472 patients underwent CBTR and 75 underwent CBETR. Mean age was 54.7 ± 16 years. Mean number of days between embolization and resection was 0.65 ± 0.72 days (range 0-3). When compared with CBTR, there were no significant differences in mortality for CBETR (1.35% vs. 0%, P = 0.316), cranial nerve injury (2.7% vs. 0%, P = 0.48), and blood loss (2.7% vs. 6.8%, P = 0.245). Following risk adjustment, CBETR increased the odds of prolonged LOS (odds ratio 5.3, 95% confidence interval 2.1-13.3). Conclusions: CBT resection is a relatively rare procedure. The utility of preoperative tumor embolization has been questioned. This study demonstrates no benefit of preoperative tumor embolization.

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Transient atrial fibrillation after open abdominal aortic revascularization surgery is associated with increased length of stay, mortality, and readmission rates

Barbara A Blanco, Anai N Kothari, Pegge M Halandras, Robert H Blackwell, Dawn M Graunke, Paul C Kuo, Jae S Cho

Background: It is well established that transient postoperative atrial fibrillation (TPAF) is associated with adverse postoperative outcomes after major cardiac and noncardiac operations. The purpose of this study was to elucidate the incidence, impact, and risk factors associated with the development of TPAF in patients undergoing revascularization surgery for occlusive diseases of the abdominal aorta and its branches (AAB). Methods: By use of the Healthcare Cost and Utilization Project State Inpatient Database from Florida and California, patients who underwent open revascularization of AAB between 2006 and 2011 were identified. Patients diagnosed with aortic dissection or abdominal aortic aneurysm were excluded to limit the study cohort to include only patients with occlusive etiology. Also excluded were those with a pre-existing diagnosis of atrial fibrillation and those who underwent thoracic aortic repair and peripheral artery revascularization procedures. Multivariable logistic and linear regression analyses with treatment effects were conducted to analyze the association between TPAF and length of stay (LOS); the mortality rates at index admission, 1 month, and 1 year; and the readmission rates at 1 month and 1 year (adjusted for comorbidities and surgical and demographic factors). A backwards stepwise logistic regression model was built to identify predictors of TPAF. Results: A total of 4462 patients were identified; 3253 underwent aortoiliac/femoral bypasses (72.9%), 1514 endarterectomies of AAB (33.9%), and 288 bypasses of AAB (6.5%). The incidence of TPAF was 2.4% (109 patients). Multivariate regression analysis with treatment effects showed that TPAF was associated with significantly increased LOS, mortality, and readmission rates. Factors identified as predictors of TPAF by backwards stepwise logistic regression modeling include electrolyte disorders, increasing age, and Charlson Comorbidity Index (C statistic = .69; accuracy = 58%). Conclusions: TPAF after revascularization of AAB is associated with increased LOS, inpatient mortality, 1-year mortality, and hospital readmissions. Strategies to identify patients at risk for development of TPAF and implementation of appropriate prophylactic measures may improve surgical outcomes and reduce cost of care.

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Impact of Post-Hospital Syndrome on Outcomes Following Elective, Ambulatory Surgery

Sarah A Brownlee, Robert H Blackwell, Barbara A Blanco, Matthew A C Zapf, Stephanie Kliethermes, Gopal N Gupta, Paul C Kuo, Anai N Kothari

Objective: The aim of this study was to investigate whether post-hospital syndrome (PHS) places patients undergoing elective hernia repair at increased risk for adverse postoperative events. Summary of background data: PHS is a transient period of health vulnerability following inpatient hospitalization for acute illness. PHS has been well studied in nonsurgical populations, but its effect on surgical outcomes is unclear. Methods: State-specific datasets for California in 2011 available through the Healthcare Cost and Utilization Project (HCUP) were linked. Patients older than 18 years who underwent elective hernia repair were included. The primary exposure variable was PHS, defined as any inpatient admission within 90 days of an elective hernia repair performed in an ambulatory surgery center. The primary outcome was an adverse event, defined as any unplanned emergency department visit or inpatient admission within 30 days postoperatively. Mixed-effects logistic models were used for multivariable analyses. Results: A total of 57,988 patients met inclusion criteria. The 30-day risk-adjusted adverse event rate was significantly higher for PHS patients versus non-PHS patients (11.8% vs 5.8%, P < 0.001). PHS patients were more likely than non-PHS patients to experience postoperative complications (odds ratio 2.2, 95% confidence interval 1.6-3.0). Adverse events attributable to PHS cost an additional $63,533.46 per 100 cases in California. The risk of adverse events due to PHS remained elevated throughout the 90-day window between hospitalization and surgery. Conclusions: Patients hospitalized within 90 days of an elective surgery are at increased risk of adverse events postoperatively. The impact of PHS on outcomes is independent of baseline patient characteristics, medical comorbidities, quality of center performing the surgery, and reason for hospitalization before elective surgery. Adverse events owing to PHS are costly and represent a quality improvement target.

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Postoperative Urinary Retention is an Independent Predictor of Short-Term and Long-Term Future Bladder Outlet Procedure in Men

Robert H Blackwell, Srikanth Vedachalam, Arpeet S Shah, Anai N Kothari, Paul C Kuo, Gopal N Gupta, Thomas M T Turk

Purpose: Postoperative urinary retention is a common complication across surgical specialties. To our knowledge no literature to date has examined postoperative urinary retention as a predictor of long-term receipt of surgery for bladder outlet obstruction. Materials and methods: We retrospectively reviewed the records of inpatients who underwent nonurological surgery in California between 2008 and 2010. Postoperative urinary retention during the index admission was identified, as was receipt of a bladder outlet procedure (transurethral prostate resection, prostate photoselective vaporization or suprapubic prostatectomy) at a subsequent encounter. Patients were matched using propensity scoring of demographics, comorbidities and surgery type. Adjusted Kaplan-Meier analysis was performed to determine the cumulative incidence of subsequent bladder outlet procedures by patient group, including group 1-age 60 years or greater and postoperative urinary retention, group 2-age 60 years or greater and no postoperative urinary retention, group 3-age less than 60 years and postoperative urinary retention, and group 4-age less than 60 years and no postoperative urinary retention. Results: Of 769,141 eligible male patients postoperative urinary retention developed in 8,051 (1.1%). Following hospital discharge 1,855 patients (0.24%) underwent a bladder outlet procedure. Those treated with a bladder outlet procedure were significantly more likely to have experienced postoperative urinary retention during the index admission (6.3% vs 1.0%, p <0.001). On matched analysis the bladder outlet procedure rate at 3 years was 7.1%, 2.2%, 0.8% and 0.0% in groups 1, 2, 3 and 4, respectively. Conclusions: In men 60 years old or older postoperative urinary retention identified those with an increased incidence of bladder outlet procedures within 3 years. Men younger than 60 years had a low rate of subsequent bladder outlet procedures regardless of a postoperative urinary retention diagnosis. Keywords: age groups; postoperative complications; urinary bladder; urinary bladder neck obstruction; urinary retention.

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"Take the Volume Pledge" may result in disparity in access to care

Barbara A Blanco, Anai N Kothari, Robert H Blackwell, Sarah A Brownlee, Ryan M Yau, John P Attisha, Yoshiki Ezure, Sam Pappas, Paul C Kuo, Gerard J Abood

Background: "Take the Volume Pledge" proposes restricting pancreatectomies to hospitals that perform ≥20 per year. Our purpose was to identify those factors that characterize patients at risk for loss of access to pancreatic cancer care with enforcement of volume standards. Methods: Using the Healthcare Cost and Utilization Project State Inpatient Database from Florida, we identified patients who underwent pancreatectomy for pancreatic malignancy from 2007-2011. American Hospital Association and United States Census Bureau data were linked to patient-level data. High-volume hospitals were defined as performing ≥20 pancreatic resections per year. Univariable and multivariable statistics compared patient characteristics and utilization of high-volume hospitals. Classification and Regression Tree modeling was used to predict patients at risk for losing access to care. Results: Our study included 1,663 patients. Five high-volume hospitals were identified, and they treated 1,056 (63.5%) patients. Patients residing far from high-volume hospitals, in areas with the highest population density, non-Caucasian ethnicity, and greater income had decreased odds of obtaining care at high-volume hospitals. Using these factors, we developed a Classification and Regression Tree-based predictive tool to identify these patients. Conclusion: Implementation of "Take the Volume Pledge" is an important step toward improving pancreatectomy outcomes; however, policymakers must consider the potential impact on limiting access and possible health disparities that may arise.

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Incidence of Adverse Contrast Reaction Following Nonintravenous Urinary Tract Imaging

Robert H Blackwell, Eric J Kirshenbaum, Matthew A C Zapf, Anai N Kothari, Paul C Kuo, Robert C Flanigan, Gopal N Gupta

Adverse reactions (ARs) to intravenous (IV) radiographic contrast range from mild urticaria to life-threatening anaphylaxis. Intraluminal contrast dye is routinely used in the urinary tract with a minimal perceived risk of AR. We used the Healthcare Cost and Utilization Project State Inpatient Databases for California and Florida from 2007 to 2011 to identify patients who received urinary tract contrast dye for retrograde pyelography, percutaneous pyelography, retrograde/other cystogram, and ileal conduitogram. After excluding patients who had received IV contrast for other radiologic studies, ARs to contrast were identified by a composite end point of diagnoses not present on admission including shock, anaphylaxis, iatrogenic hypotension, urticaria, angioedema, laryngospasm, laryngeal edema, and/or a new diagnosis of contrast reaction. Overall, 76 174 patients were included who had undergone non-IV urinary tract imaging, 367 (0.48%) of whom developed an AR. On multivariate analysis, receipt of contrast in the lower urinary tract (odds ratio [OR]: 1.8; p=0.04) or upper urinary tract by retrograde pyelography (OR: 1.6; p=0.04) or antegrade pyelography (OR: 2.0; p=0.007) increased the risk of AR compared with control patients. The use of contrast dye in the urinary tract is associated with a low, but present risk of AR. Patient summary: We looked at patients who underwent a urologic procedure using radiographic contrast media in the urinary tract. Although adverse reactions (ARs) may occur with the use of contrast media in the urinary tract, these reactions are experienced by a minority of patients (approximately 1 in 200). In addition, we found that an allergy to intravenous contrast does not increase a patient's risk of an AR to contrast within the urinary tract. Keywords: Adverse drug reaction; Contrast media; Hypersensitivity; Urography

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Outcomes of percutaneous nephrolithotomy in spinal cord injury patients as compared to a matched cohort

Kristin G Baldea, Robert H Blackwell, Srikanth Vedachalam, Anai N Kothari, Paul C Kuo, Gopal N Gupta, Thomas M T Turk

Spinal cord injury patients are at increased risk of developing nephrolithiasis and may require percutaneous nephrolithotomy for treatment of large stone burdens. Our objective was to compare outcomes of PCNL in SCI patients as compared to a matched cohort of non-SCI patients. Data from the Healthcare Cost and Utilization Project State Inpatient Database for Florida and California were used to identify patients by ICD-9 codes who underwent PCNL between 2007 and 2011. SCI was identified by having a paralysis diagnosis on the chronic comorbidity indicator. One-to-one matching was performed based on age, race, gender, presence of preoperative UTI, and major comorbidities. Of the 39,868 unique patients identified, who underwent PCNL, 1918 (4.81%) were SCI patients. After matching, worse perioperative outcomes in SCI patients were demonstrated. SCI patients had significantly longer length of stay, higher rates of sepsis, and increased minor and moderate complications (p < 0.001). Multivariate analysis demonstrated an independently increased risk of mortality, minor and major complications, pneumonia, sepsis, and length of stay in SCI patients. PCNL in SCI patients is associated with a high complication rate and longer hospital stay even when controlling for presence of preoperative UTI and medical comorbidities. To our knowledge, this is the first study of outcomes of PCNL in a large population of SCI patients. These patients represent a high risk population and strategies to decrease complications need to be developed and implemented.

Keywords: Nephrolithiasis; Percutaneous nephrolithotomy; Spinal cord injuries; Treatment outcomes

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Impact of hospital transfer on surgical outcomes of intestinal atresia

T Erickson, P G Vana, B A Blanco, S A Brownlee, H N Paddock, P C Kuo, A N Kothari

Background: Examine effects of hospital transfer into a quaternary care center on surgical outcomes of intestinal atresia. Methods: Children <1 yo principally diagnosed with intestinal atresia were identified using the Kids' Inpatient Database (2012). Exposure variable was patient transfer status. Outcomes measured were inpatient mortality, hospital length of stay (LOS) and discharge status. Linearized standard errors, design-based F tests, and multivariable logistic regression were performed. Results: 1672 weighted discharges represented a national cohort. The highest income group and those with private insurance had significantly lower odds of transfer (OR:0.53 and 0.74, p < 0.05). Rural patients had significantly higher transfer rates (OR: 2.73, p < 0.05). Multivariate analysis revealed no difference in mortality (OR:0.71, p = 0.464) or non-home discharge (OR: 0.79, p = 0.166), but showed prolonged LOS (OR:1.79, p < 0.05) amongst transferred patients. Conclusions: Significant differences in hospital LOS and treatment access reveal a potential healthcare gap. Post-acute care resources should be improved for transferred patients. Keywords: Atresia; Pediatrics; Regionalization; Surgery

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Physiologic Response to HIPEC: Sifting Through Perturbation to Identify Markers of Complications

Timothy P Plackett, Hieu H Ton-That, Michael J Mosier, Gerard J Abood, Paul C Kuo, Sam G Pappas

Context: The postoperative physiologic response to hyperthermic intraperitoneal chemotherapy (HIPEC) has been poorly studied outside of the immediate perioperative time. Objective: To characterize the physiologic response during the first 5 days after HIPEC and identify variables associated with major complications. Methods: Patients undergoing HIPEC and cytoreductive surgery during a 14-month interval were retrospectively identified and their records reviewed for demographics, physiologic response, and major complications. Vital signs and laboratory results were recorded before the operation, immediately after the procedure, and for the first 5 postoperative days. Results: Thirty-three patients were included. The mean body temperature and heart rate were elevated on postoperative day 1 compared with baseline (preoperative) status (37.1°C vs 36.6°C and 103 vs 78 beats/min, respectively) and remained elevated through postoperative day 5. The mean arterial pressure was lower on postoperative day 1 (73 mm Hg) but returned to baseline on postoperative day 3 (93 mm Hg). Mean creatinine level increased on postoperative day 1 (0.96 mg/dL) but returned to baseline on postoperative day 2 (0.87 mg/dL). Fourteen patients (42%) had major complications. The strongest predictors of major complications were a prolonged operative time (519 vs 403 minutes) and extreme changes in body temperature and renal function. Conclusions: Hyperthermic intraperitoneal chemotherapy results in a hypermetabolic response that partially returns to baseline around postoperative day 3. Elevated body temperature and impaired renal function are the best predictors of major complications.

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Incidence of Adverse Contrast Reaction Following Nonintravenous Urinary Tract Imaging.

Blackwell RH, Kirshenbaum EJ, Zapf MAC, Kothari AN, Kuo PC, Flanigan RC, Gupta GN

Adverse reactions (ARs) to intravenous (IV) radiographic contrast range from mild urticaria to life-threatening anaphylaxis. Intraluminal contrast dye is routinely used in the urinary tract with a minimal perceived risk of AR. We used the Healthcare Cost and Utilization Project State Inpatient Databases for California and Florida from 2007 to 2011 to identify patients who received urinary tract contrast dye for retrograde pyelography, percutaneous pyelography, retrograde/other cystogram, and ileal conduitogram. After excluding patients who had received IV contrast for other radiologic studies, ARs to contrast were identified by a composite end point of diagnoses not present on admission including shock, anaphylaxis, iatrogenic hypotension, urticaria, angioedema, laryngospasm, laryngeal edema, and/or a new diagnosis of contrast reaction. Overall, 76 174 patients were included who had undergone non-IV urinary tract imaging, 367 (0.48%) of whom developed an AR. On multivariate analysis, receipt of contrast in the lower urinary tract (odds ratio [OR]: 1.8; p=0.04) or upper urinary tract by retrograde pyelography (OR: 1.6; p=0.04) or antegrade pyelography (OR: 2.0; p=0.007) increased the risk of AR compared with control patients. The use of contrast dye in the urinary tract is associated with a low, but present risk of AR. Patient Summary: We looked at patients who underwent a urologic procedure using radiographic contrast media in the urinary tract. Although adverse reactions (ARs) may occur with the use of contrast media in the urinary tract, these reactions are experienced by a minority of patients (approximately 1 in 200). In addition, we found that an allergy to intravenous contrast does not increase a patient's risk of an AR to contrast within the urinary tract.

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Postoperative Urinary Retention is an Independent Predictor of Short-Term and Long-Term Future Bladder Outlet Procedure in Men

Blackwell RH, Vedachalam S, Shah AS, Kothari AN, Kuo PC, Gupta GN, Turk TMT

Purpose: Postoperative urinary retention is a common complication across surgical specialties. To our knowledge no literature to date has examined postoperative urinary retention as a predictor of long-term receipt of surgery for bladder outlet obstruction. Materials and Methods: We retrospectively reviewed the records of inpatients who underwent nonurological surgery in California between 2008 and 2010. Postoperative urinary retention during the index admission was identified, as was receipt of a bladder outlet procedure (transurethral prostate resection, prostate photoselective vaporization or suprapubic prostatectomy) at a subsequent encounter. Patients were matched using propensity scoring of demographics, comorbidities and surgery type. Adjusted Kaplan-Meier analysis was performed to determine the cumulative incidence of subsequent bladder outlet procedures by patient group, including group 1-age 60 years or greater and postoperative urinary retention, group 2-age 60 years or greater and no postoperative urinary retention, group 3-age less than 60 years and postoperative urinary retention, and group 4-age less than 60 years and no postoperative urinary retention. Results: Of 769,141 eligible male patients postoperative urinary retention developed in 8,051 (1.1%). Following hospital discharge 1,855 patients (0.24%) underwent a bladder outlet procedure. Those treated with a bladder outlet procedure were significantly more likely to have experienced postoperative urinary retention during the index admission (6.3% vs 1.0%, p <0.001). On matched analysis the bladder outlet procedure rate at 3 years was 7.1%, 2.2%, 0.8% and 0.0% in groups 1, 2, 3 and 4, respectively. Conclusions: In men 60 years old or older postoperative urinary retention identified those with an increased incidence of bladder outlet procedures within 3 years. Men younger than 60 years had a low rate of subsequent bladder outlet procedures regardless of a postoperative urinary retention diagnosis. Keywords: age groups; postoperative complications; urinary bladder; urinary bladder neck obstruction; urinary retention

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Discordance between surgical care improvement project adherence and postoperative outcomes: implications for new Joint Commission standards

Chang V, Blackwell RH, Markossian T, Yau RM, Blanco BA, Zapf MAC, Abood GJ, Gupta GN, Kuo PC, Kothari AN

Background: Infectious (INF) and venous thromboembolism (VTE) complication rates are targeted by surgical care improvement project (SCIP) INF and SCIP VTE measures. We analyzed how adherence to SCIP INF and SCIP VTE affects targeted postoperative outcomes (wound complication [WC], deep vein thrombosis, and pulmonary embolism [PE]) using all-payer data. Materials and Methods: A retrospective review (2007-2011) was conducted using Healthcare Cost and Utilization Project State Inpatient Database Florida and Medicare's Hospital Compare. The association between SCIP adherence rates and outcomes across 355 included surgical procedures was measured using multilevel mixed-effects linear regression models. Results: One hundred sixty acute care hospitals and 779,922 patients were included. Over 5 y, SCIP INF-1, -2, and -3 adherence improved by 12.5%, 8.0%, and 20.9%, respectively, whereas postoperative WC rate decreased by 14.8%. When controlling for time, SCIP INF-1 adherence was associated with improvement of postoperative WC rates (β = -0.0044, P = 0.005), whereas SCIP INF-2 adherence was associated with increased WCs (β = 0.0031, P = 0.018). SCIP VTE-1, -2 adherence improved by 14.6% and 20.2%, respectively, whereas postoperative deep vein thrombosis rate increased by 7.1% and postoperative PE rate increased by 3.7%. SCIP VTE-1 and -2 adherence were both associated with increased postoperative PE when controlling for time (SCIP VTE-1: β = 0.0019, P < 0.001; SCIP VTE-2: β = 0.0015, P < 0.001). Readmission analysis found SCIP INF-1 adherence to be associated with improved 30-d WC rates when controlling for patient and hospital characteristics (β = -0.0021, P = 0.032), whereas SCIP INF-3 adherence was associated with increased 30-d WC rates when controlling for time (β = 0.0007, P = 0.04). Conclusions : Only SCIP INF-1 adherence was associated with improved outcomes. The Joint Commission has retired SCIP INF-2, -3, and SCIP VTE-2 and made SCIP INF-1 and VTE-1 reporting optional. Our study supports continued reporting of SCIP INF-1.

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Rates and Risk Factors for Opioid Dependence and Overdose after Urological Surgery

Shah AS, Blackwell RH, Kuo PC, Gupta GN

Purpose : Effective pain management is a critical component of the perioperative process with opioids representing a mainstay of therapy. The opioid epidemic is a growing concern in the United States. The goal of this study was to quantify the risk of opioid dependence or overdose among patients undergoing urological surgery and to identify risk factors of opioid dependence or overdose. Materials and Methods: We retrospectively reviewed data on urological surgery from 2007 to 2011. Data sources included the HCUP (Healthcare Cost and Utilization Project) inpatient, ambulatory surgery and emergency department data sets. Outcomes of postoperative opioid dependence and overdose were identified by previously validated ICD-9 codes. Multivariable logistic regression adjusted for surgical procedure was performed to identify predictors of opioid dependence or overdose following urological surgery. Results : Overall 675,527 patients underwent urological surgery, of whom 0.09% were diagnosed with opioid dependence or overdose. Patients in whom opioid dependence or overdose developed were younger (median age 51 vs 62 years), carried nonprivate insurance (69.6% vs 66%), underwent an inpatient procedure (81.0% vs 42.4%) and had a longer length of stay (median 3 vs 0 days) and a history of depression (14.4% vs 3.4%) or chronic obstructive pulmonary disease (20.3% vs 8.9%, all p <0.001). On adjusted multivariable analysis these factors remained independent risk factors for opioid dependence or overdose. Conclusions: Postoperative opioid dependence or overdose affects 1 of 1,111 urological surgery patients. Risk factors for opioid dependence or overdose included younger age, inpatient surgery and increasing hospitalization duration, baseline depression, tobacco use and chronic obstructive pulmonary disease as well as insurance provider, including Medicaid, Medicare (age less than 65 years) and noninsured status.

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Adverse Effect of Post-Discharge Care Fragmentation on Outcomes after Readmissions after Liver Transplantation

Kothari AN, Loy VM, Brownlee SA, Ezure Y, Schaidle-Blackburn C, Cotler SJ, di Sabato D, Kuo PC, Lu AD

Background: Post-discharge surgical care fragmentation is defined as readmission to any hospital other than the hospital at which surgery was performed. The objective of this study was to assess the impact of fragmented readmissions within the first year after orthotopic liver transplantation (OLT). Study Design: The Healthcare Cost and Utilization Project State Inpatient Databases for Florida and California from 2006 to 2011 were used to identify OLT patients. Post-discharge fragmentation was defined as any readmission to a non-index hospital, including readmitted patients transferred to the index hospital after 24 hours. Outcomes included adverse events, defined as 30-day mortality and 30-day readmission after a fragmented readmission. All statistical analyses considered a hierarchical data structure and were performed with multilevel, mixed-effects models. Results: We analyzed 2,996 patients with 7,485 readmission encounters at 299 hospitals; 1,236 (16.5%) readmissions were fragmented. After adjustment for age, sex, readmission reason, index liver transplantation cost, readmission length of stay, number of previous readmissions, and time from transplantation, post-discharge fragmentation increased the odds of both 30-day mortality (odds ratio [OR] = 1.75; 95% CI 1.16 to 2.65) and 30-day readmission (OR = 2.14; 95% CI 1.83 to 2.49). Predictors of adverse events after a fragmented readmission included increased number of previous readmissions (OR = 1.07; 95% CI 1.01 to 1.14) and readmission within 90 days of OLT (OR = 2.19; 95% CI 1.61 to 2.98). Conclusions: Post-discharge fragmentation significantly increases the risk of both 30-day mortality and subsequent readmission after a readmission in the first year after OLT. More inpatient visits before a readmission and less time elapsed from index surgery increase the odds of an adverse event after discharge from a fragmented readmission. These parameters could guide transfer decisions for patients with post-discharge fragmentation.

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Association Between Elements of Electronic Health Record Systems and the Weekend Effect in Urgent General Surgery

Kothari AN, Brownlee SA, Blackwell RH, Zapf MAC, Markossian T, Gupta GN, Kuo PC

Temporal disparities in care are increasingly being recognized as important determinants of health outcomes. These disparities are characterized by differences in outcomes based on the time when care is delivered and include several well-studied phenomena including the “weekend effect.”

Like many disparities in health care, there is potential for temporal disparities to be overcome. Previous study has shown that fully implemented electronic health record (EHR) systems can help hospitals overcome the weekend effect for patients undergoing urgent general surgical procedures. We evaluated how specific components of EHR systems were associated with the weekend effect.

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Transient atrial fibrillation after open abdominal aortic revascularization surgery is associated with increased length of stay, mortality, and readmission rates

Blanco BA, Kothari AN, Halandras PM, Blackwell RH, Graunke DM, Kuo PC, Cho JS

Background: It is well established that transient postoperative atrial fibrillation (TPAF) is associated with adverse postoperative outcomes after major cardiac and noncardiac operations. The purpose of this study was to elucidate the incidence, impact, and risk factors associated with the development of TPAF in patients undergoing revascularization surgery for occlusive diseases of the abdominal aorta and its branches (AAB). Methods: By use of the Healthcare Cost and Utilization Project State Inpatient Database from Florida and California, patients who underwent open revascularization of AAB between 2006 and 2011 were identified. Patients diagnosed with aortic dissection or abdominal aortic aneurysm were excluded to limit the study cohort to include only patients with occlusive etiology. Also excluded were those with a pre-existing diagnosis of atrial fibrillation and those who underwent thoracic aortic repair and peripheral artery revascularization procedures. Multivariable logistic and linear regression analyses with treatment effects were conducted to analyze the association between TPAF and length of stay (LOS); the mortality rates at index admission, 1 month, and 1 year; and the readmission rates at 1 month and 1 year (adjusted for comorbidities and surgical and demographic factors). A backwards stepwise logistic regression model was built to identify predictors of TPAF. Results : A total of 4462 patients were identified; 3253 underwent aortoiliac/femoral bypasses (72.9%), 1514 endarterectomies of AAB (33.9%), and 288 bypasses of AAB (6.5%). The incidence of TPAF was 2.4% (109 patients). Multivariate regression analysis with treatment effects showed that TPAF was associated with significantly increased LOS, mortality, and readmission rates. Factors identified as predictors of TPAF by backwards stepwise logistic regression modeling include electrolyte disorders, increasing age, and Charlson Comorbidity Index (C statistic = .69; accuracy = 58%). Conclusions: TPAF after revascularization of AAB is associated with increased LOS, inpatient mortality, 1-year mortality, and hospital readmissions. Strategies to identify patients at risk for development of TPAF and implementation of appropriate prophylactic measures may improve surgical outcomes and reduce cost of care.

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Acute Kidney Injury in Burn Patients: Clinically Significant Over the Initial Hospitalization and 1 Year After Injury: An Original Retrospective Cohort Study

Thalji SZ, Kothari AN, Kuo PC, Mosier MJ

Objective: To examine the development of acute kidney injury (AKI) after burn injury as an independent risk factor for increased morbidity and mortality over initial hospitalization and 1-year follow-up. Background: Variability in fluid resuscitation and difficulty recognizing early sepsis are major barriers to preventing AKI after burn injury. Expanding our understanding of the burden AKI has on the clinical course of burn patients would highlight the need for standardized protocols. Methods: We queried the Healthcare Cost and Utilization Project State Inpatient Databases in the states of Florida and New York during the years 2009 to 2013 for patients over age 18 hospitalized with a primary diagnosis of burn injury using ICD-9 codes. We identified and grouped 18,155 patients, including 1476 with burns >20% total body surface area, by presence of AKI. Outcomes were compared in these cohorts via univariate analysis and multivariate logistic regression models. Results: During initial hospitalization, AKI was associated with increased pulmonary failure, mechanical ventilation, pneumonia, myocardial infarction, length of stay, cost, and mortality, and also a lower likelihood of being discharged home. One year after injury, AKI was associated with development of chronic kidney disease, conversion to chronic dialysis, hospital readmission, and long-term mortality. Conclusions: AKI is associated with a profound and severe increase in morbidity and mortality in burn patients during initial hospitalization and up to 1 year after injury. Consensus protocols for initial burn resuscitation and early sepsis recognition and treatment are crucial to avoid the consequences of AKI after burn injury.

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Impact of Post-Hospital Syndrome on Outcomes Following Elective, Ambulatory Surgery

Brownlee SA, Blackwell RH, Blanco BA, Zapf MAC, Kliethermes S, Gupta GN, Kuo PC, Kothari AN

Objective: The aim of this study was to investigate whether post-hospital syndrome (PHS) places patients undergoing elective hernia repair at increased risk for adverse postoperative events. Summary and Background Data: PHS is a transient period of health vulnerability following inpatient hospitalization for acute illness. PHS has been well studied in nonsurgical populations, but its effect on surgical outcomes is unclear. Methods: State-specific datasets for California in 2011 available through the Healthcare Cost and Utilization Project (HCUP) were linked. Patients older than 18 years who underwent elective hernia repair were included. The primary exposure variable was PHS, defined as any inpatient admission within 90 days of an elective hernia repair performed in an ambulatory surgery center. The primary outcome was an adverse event, defined as any unplanned emergency department visit or inpatient admission within 30 days postoperatively. Mixed-effects logistic models were used for multivariable analyses. Results: A total of 57,988 patients met inclusion criteria. The 30-day risk-adjusted adverse event rate was significantly higher for PHS patients versus non-PHS patients (11.8% vs 5.8%, P < 0.001). PHS patients were more likely than non-PHS patients to experience postoperative complications (odds ratio 2.2, 95% confidence interval 1.6-3.0). Adverse events attributable to PHS cost an additional $63,533.46 per 100 cases in California. The risk of adverse events due to PHS remained elevated throughout the 90-day window between hospitalization and surgery. Conclusions: Patients hospitalized within 90 days of an elective surgery are at increased risk of adverse events postoperatively. The impact of PHS on outcomes is independent of baseline patient characteristics, medical comorbidities, quality of center performing the surgery, and reason for hospitalization before elective surgery. Adverse events owing to PHS are costly and represent a quality improvement target.

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Perioperative support, not volume, is necessary to optimize outcomes in surgical management of necrotizing enterocolitis

Cobb AN, Wong YM, Brownlee SA, Blanco BA, Ezure Y, Paddock HN, Kuo PC, Kothari AN

Background: This study examines the relationship between hospital volume of surgical cases for necrotizing enterocolitis (NEC) and patient outcomes. Methods: A retrospective cross-sectional review was performed using the HCUP SID for California from 2007 to 2011. Patients with NEC who underwent surgery were identified using ICD-9CM codes. Risk-adjusted models were constructed with mixed-effects logistic regression using patient and demographic covariates. Results: 23 hospitals with 618 patients undergoing NEC-related surgical intervention were included. Overall mortality rate was 22.5%. There were no significant differences in the number of NICU beds (p = 0.135) or NICU intensivists (p = 0.469) between high and low volume hospitals. Following risk adjustment, no difference in mortality rate was observed between high and low volume hospitals respectively (24.0% vs. 20.3%, p = 0.555). Conclusions: Our observation that neonates with NEC treated at low-volume centers have no increased risk of mortality may be explained by similar availability of NICU and intensivists resources across hospitals.

Keywords: Care delivery microenvironment; NEC; Necrotizing enterocolitis; Pediatric surgery; Surgical outcomes

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Outcomes of percutaneous nephrolithotomy in spinal cord injury patients as compared to a matched cohort

Baldea KG, Blackwell RH, Vedachalam S, Kothari AN, Kuo PC, Gupta GN, Turk TMT

Spinal cord injury patients are at increased risk of developing nephrolithiasis and may require percutaneous nephrolithotomy for treatment of large stone burdens. Our objective was to compare outcomes of PCNL in SCI patients as compared to a matched cohort of non-SCI patients. Data from the Healthcare Cost and Utilization Project State Inpatient Database for Florida and California were used to identify patients by ICD-9 codes who underwent PCNL between 2007 and 2011. SCI was identified by having a paralysis diagnosis on the chronic comorbidity indicator. One-to-one matching was performed based on age, race, gender, presence of preoperative UTI, and major comorbidities. Of the 39,868 unique patients identified, who underwent PCNL, 1918 (4.81%) were SCI patients. After matching, worse perioperative outcomes in SCI patients were demonstrated. SCI patients had significantly longer length of stay, higher rates of sepsis, and increased minor and moderate complications (p < 0.001). Multivariate analysis demonstrated an independently increased risk of mortality, minor and major complications, pneumonia, sepsis, and length of stay in SCI patients. PCNL in SCI patients is associated with a high complication rate and longer hospital stay even when controlling for presence of preoperative UTI and medical comorbidities. To our knowledge, this is the first study of outcomes of PCNL in a large population of SCI patients. These patients represent a high risk population and strategies to decrease complications need to be developed and implemented. Keywords: Nephrolithiasis; Percutaneous nephrolithotomy; Spinal cord injuries; Treatment outcomes

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Variable surgical outcomes after hospital consolidation: Implications for local health care delivery

Chang V, Blackwell RH, Yau RM, Besser S, Albright JM, Gupta GN, Kuo PC, Kothari AN

Background: With more hospital consolidations as an inevitable part of our future health care ecosystem, we investigated the relationship between hospital consolidations and operative outcomes. Methods: Using the Health Care Cost and Utilization Project State Inpatient Database (Florida and California), the American Hospital Association Annual Survey Database, and Medicare's Case Mix Index data, we identified 19 hospitals that consolidated between 2007 and 2013 and propensity matched them with 19 independent hospitals, using patient and hospital characteristics. One year before consolidation and again 1 year after, we used difference-in-differences analysis to compare changes in the risk-adjusted complication rate of 7 elective operations performed in the consolidated hospitals and in the matched control group. Results: Of the 7 procedures studied, 2 procedures saw a decrease in complication rate (lumbar and lumbosacral fusion of the posterior column posterior technique, difference-in-differences = -0.6%, P < .01; total hip replacement, difference-in-differences = -0.6%, P < .01); 3 procedures saw an increase in complication rate (transurethral prostatectomy, difference-in-differences = 4.1%, P < .01; cervical fusion of the anterior column anterior technique, difference-in-differences = 1.5%, P < .01; total knee replacement, difference-in-differences = 0.3%, P < .01); and 2 procedures saw no change in complication rate (laparoscopic cholecystectomy, lumbar and lumbosacral fusion of the anterior column posterior technique, both P > .05) after hospital consolidation. Conclusion: Arguments have been made that consolidated health care systems can share high-performing clinical services and infrastructure resources, such as electronic medical records, to improve quality. Our results indicate that hospital consolidation does not uniformly improve postoperative complication rates.

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Characterizing the role of a high-volume cancer resection ecosystem on low-volume, high-quality surgical care

Kothari AN, Blanco BA, Brownlee SA, Evans AE, Chang VA, Abood GJ, Settimi R, Raicu DS, Kuo PC

Background: Our objective was to determine the hospital resources required for low-volume, high-quality care at high-volume cancer resection centers. Methods: Patients who underwent esophageal, pancreatic, and rectal resection for malignancy were identified using Healthcare Cost and Utilization Project State Inpatient Database (Florida and California) between 2007 and 2011. Annual case volume by procedure was used to identify high- and low-volume centers. Hospital data were obtained from the American Hospital Association Annual Survey Database. Procedure risk-adjusted mortality was calculated for each hospital using multilevel, mixed-effects models. Results: A total of 24,784 patients from 302 hospitals met the inclusion criteria. Of these, 13 hospitals were classified as having a high-volume, oncologic resection ecosystem by being a high-volume hospital for ≥2 studied procedures. A total of 11 of 31 studied hospital factors were strongly associated with hospitals that performed a high volume of cancer resections and were used to develop the High Volume Ecosystem for Oncologic Resections (HIVE-OR) score. At low-volume centers, increasing HIVE-OR score resulted in decreased mortality for rectal cancer resection (P = .038). HIVE-OR was not related to risk-adjusted mortality for esophagectomy (P = .421) or pancreatectomy (P = .413) at low-volume centers. Conclusion: Our study found that in some settings, low-volume, high-quality cancer surgical care can be explained by having a high-volume ecosystem.

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Inpatient Rehabilitation after Liver Transplantation Decreases Risk and Severity of 30-Day Readmissions

Kothari AN, Yau RM, Blackwell RH, Schaidle-Blackburn C, Markossian T, Zapf MA, Lu AD, Kuo PC

Background: Discharge location is associated with short-term readmission rates after hospitalization for several medical and surgical diagnoses. We hypothesized that discharge location: home, home health, skilled nursing facility (SNF), long-term acute care (LTAC), or inpatient rehabilitation, independently predicted the risk of 30-day readmission and severity of first readmission after orthotopic liver transplantation. Study Design: We performed a retrospective cohort review using Healthcare Cost and Utilization Project (HCUP) State Inpatient Databases for Florida and California. Patients who underwent orthotopic liver transplantation from 2009 to 2011 were included and followed for 1 year. Mixed-effects logistic regression was used to model the effect of discharge location on 30-day readmission controlling for demographic, socioeconomic, and clinical factors. Total cost of first readmission was used as a surrogate measure for readmission severity and resource use. Results: A total of 3,072 patients met our inclusion criteria. The overall 30-day readmission rate was 29.6%. Discharge to inpatient rehabilitation (adjusted odds ratio [aOR] 0.43, p = 0.013) or LTAC/SNF (aOR 0.63, p = 0.014) were associated with decreased odds of 30-day readmission when compared with home. The severity of 30-day readmissions for patients discharged to inpatient rehabilitation were the same as those discharged home or home with home health. Severity was increased for those discharged to LTAC/SNF. The time to first readmission was longest for patients discharged to inpatient rehabilitation (17 days vs 8 days, p < 0.001). Conclusions: When compared with other locations of discharge, inpatient rehabilitation reduces the risk of 30-day readmission and increases the time to first readmission. These benefits come without increasing the severity of readmission. Increased use of inpatient rehabilitation after orthotopic liver transplantation is a strategy to improve 30-day readmission rates.

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Transient postoperative atrial fibrillation after abdominal aortic aneurysm repair increases mortality risk

Kothari AN, Halandras PM, Drescher M, Blackwell RH, Graunke DM, Kliethermes S, Kuo PC, Cho JS

Objective: The purpose of this study was to determine whether new-onset transient postoperative atrial fibrillation (TPAF) affects mortality rates after abdominal aortic aneurysm (AAA) repair and to identify predictors for the development of TPAF. Methods: Patients who underwent open aortic repair or endovascular aortic repair for a principal diagnosis AAA were retrospectively identified using the Healthcare Cost and Utilization Project-State Inpatient Database (Florida) for 2007 to 2011 and monitored longitudinally for 1 year. Inpatient and 1-year mortality rates were compared between those with and without TPAF. TPAF was defined as new-onset atrial fibrillation that developed in the postoperative period and subsequently resolved in patients without a history of atrial fibrillation. Cox proportional hazards models, adjusted for age, gender, comorbidities, rupture status, and repair method, were used to assess 1-year survival. Predictive models were built with preoperative patient factors using Chi-squared Automatic Interaction Detector decision trees and externally validated on patients from California. Results: A 3.7% incidence of TPAF was identified among 15,148 patients who underwent AAA repair. The overall mortality rate was 4.3%. The inpatient mortality rate was 12.3% in patients with TPAF vs 4.0% in those without TPAF. In the ruptured setting, the difference in mortality was similar between groups (33.7% vs 39.9%, P = .3). After controlling for age, gender, comorbid disease severity, urgency (ruptured vs nonruptured), and repair method, TPAF was associated with increased 1-year postoperative mortality (hazard ratio, 1.48; P < .001) and postdischarge mortality (hazard ratio, 1.56; P = .028). Chi-squared Automatic Interaction Detector-based models (C statistic = 0.70) were integrated into a Web-based application to predict an individual's probability of developing TPAF at the point of care. Conclusions: The development of TPAF is associated with an increased risk of mortality in patients undergoing repair of nonruptured AAA. Predictive modeling can be used to identify those patients at highest risk for developing TPAF and guide interventions to improve outcomes.

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New onset postoperative atrial fibrillation predicts long-term cardiovascular events after gastrectomy

Nassoiy SP, Blackwell RH, Kothari AN, Besser S, Gupta GN, Kuo PC, Abood GJ

Background: Recent evidence suggests transient postoperative atrial fibrillation leads to future cardiovascular events, even in noncardiac surgery. The long-term effects of postoperative atrial fibrillation in gastrectomy patients are unknown. Methods: The Healthcare Cost and Utilization Project State Inpatient Databases identified patients undergoing gastrectomy for malignancy between 2007 and 2010. Patients were matched by propensity scores based on various factors. Adjusted Kaplan-Meier and Cox proportional hazards models assessed the effect of postoperative atrial fibrillation on cardiovascular events. Results: A higher incidence of cardiovascular events occurred over the 1st year in patients who developed postoperative atrial fibrillation. Cox proportional hazards regression confirmed an increased risk of cardiovascular events in postoperative atrial fibrillation patients. Conclusions: Our results demonstrate that patients undergoing gastrectomy for malignancy who develop postoperative atrial fibrillation are at increased risk of cardiovascular events within 1 year. Physicians should be vigilant in assessing postoperative atrial fibrillation, given the increased risk of cardiovascular morbidity. Keywords: Atrial fibrillation; Gastrectomy; Myocardial infarction; Postoperative complications; Stroke

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Early Intervention during Acute Stone Admissions: Revealing "The Weekend Effect" in Urological Practice

Robert H Blackwell, Gregory J Barton , Anai N Kothari , Matthew A C Zapf  , Robert C Flanigan  , Paul C Kuo, Gopal N Gupta 

Purpose: Obstructing nephrolithiasis is a common condition that can require urgent intervention. In this study we analyze patient factors that contribute to delayed intervention during acute stone admission. Materials and methods: We retrospectively reviewed the HCUP SID (Healthcare Cost and Utilization Project State Inpatient Database) for Florida and California from 2007 to 2011. Patients who were admitted urgently with nephrolithiasis and an indication for decompression (urinary tract infection, acute renal insufficiency and/or sepsis) were included in the study. Intervention was timely or delayed, defined as a procedure that occurred within or after 48 hours, respectively. Adjusted multivariate models were fit to assess factors that predicted a delayed procedure as well as mortality. Results: Overall 10,301 patients were admitted urgently for nephrolithiasis with indications for decompression. Early intervention occurred in 6,689 patients (65%) and was associated with a decrease in mortality (11, 0.16%), compared to delayed intervention (17 of 3,612, 0.47%, p=0.002). On multivariate analysis timely intervention significantly decreased the odds of inpatient mortality (OR 0.43, p=0.044). Weekend day admission significantly influenced time to intervention, decreasing patient odds of timely intervention by 26% (p <0.001). Other factors decreasing patient odds of timely intervention included nonCaucasian race and nonprivate insurance. Presenting medical diagnoses of urinary tract infection, sepsis and acute renal failure did not appear to influence time to intervention. Conclusions: Delayed operative intervention for acute nephrolithiasis admissions with indications for decompression results in increased patient mortality. Nonmedical factors such as the "weekend effect," race and insurance provider exerted the greatest influence on the timing of intervention. Keywords: outcome assessment (health care); socioeconomic factors; urinary calculi; urologic surgical procedures

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Variable surgical outcomes after hospital consolidation: Implications for local health care delivery

Victor Chang, Robert H Blackwell, Ryan M Yau, Stephanie Besser, Joslyn M Albright, Gopal N Gupta, Paul C Kuo, Anai N Kothari 

Background: With more hospital consolidations as an inevitable part of our future health care ecosystem, we investigated the relationship between hospital consolidations and operative outcomes. Methods: Using the Health Care Cost and Utilization Project State Inpatient Database (Florida and California), the American Hospital Association Annual Survey Database, and Medicare's Case Mix Index data, we identified 19 hospitals that consolidated between 2007 and 2013 and propensity matched them with 19 independent hospitals, using patient and hospital characteristics. One year before consolidation and again 1 year after, we used difference-in-differences analysis to compare changes in the risk-adjusted complication rate of 7 elective operations performed in the consolidated hospitals and in the matched control group. Results: Of the 7 procedures studied, 2 procedures saw a decrease in complication rate (lumbar and lumbosacral fusion of the posterior column posterior technique, difference-in-differences = -0.6%, P < .01; total hip replacement, difference-in-differences = -0.6%, P < .01); 3 procedures saw an increase in complication rate (transurethral prostatectomy, difference-in-differences = 4.1%, P < .01; cervical fusion of the anterior column anterior technique, difference-in-differences = 1.5%, P < .01; total knee replacement, difference-in-differences = 0.3%, P < .01); and 2 procedures saw no change in complication rate (laparoscopic cholecystectomy, lumbar and lumbosacral fusion of the anterior column posterior technique, both P > .05) after hospital consolidation. Conclusion: Arguments have been made that consolidated health care systems can share high-performing clinical services and infrastructure resources, such as electronic medical records, to improve quality. Our results indicate that hospital consolidation does not uniformly improve postoperative complication rates.

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Components of Hospital Perioperative Infrastructure Can Overcome the Weekend Effect in Urgent General Surgery Procedures

Kothari AN, Zapf MA, Blackwell RH, Markossian T, Chang V, Mi Z, Gupta GN, Kuo PC

Objective: We hypothesized that perioperative hospital resources could overcome the "weekend effect" (WE) in patients undergoing emergent/urgent surgeries. Summary Background Data: The WE is the observation that surgeon-independent patient outcomes are worse on the weekend compared with weekdays. The WE is often explained by differences in staffing and resources resulting in variation in care between the week and weekend. Methods: Emergent/urgent surgeries were identified using the Healthcare Cost and Utilization Project State Inpatient Database (Florida) from 2007 to 2011 and linked to the American Hospital Association (AHA) Annual Survey Database to determine hospital level characteristics. Extended median length of stay (LOS) on the weekend compared with the weekdays (after controlling for hospital, year, and procedure type) was selected as a surrogate for WE. Results: Included were 126,666 patients at 166 hospitals. A total of 17 hospitals overcame the WE during the study period. Logistic regression, controlling for patient characteristics, identified full adoption of electronic medical records (OR 4.74), home health program (OR 2.37), pain management program [odds ratio (OR) 1.48)], increased registered nurse-to-bed ratio (OR 1.44), and inpatient physical rehabilitation (OR 1.03) as resources that were predictors for overcoming the WE. The prevalence of these factors in hospitals exhibiting the WE for all 5 years of the study period were compared with those hospitals that overcame the WE (P < 0.001). Conclusions: Specific hospital resources can overcome the WE seen in urgent general surgery procedures. Improved hospital perioperative infrastructure represents an important target for overcoming disparities in surgical care.

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"Right place at the right time" impacts outcomes for acute intestinal obstruction

Kothari AN, Liles JL, Holmes CJ, Zapf MA, Blackwell RH, Kliethermes S, Kuo PC, Luchette FA

Background: The purpose of this study was to measure how the duration of nonoperative intervention for intestinal obstruction impacted patient outcomes and whether hospital characteristics influenced the timing of operative intervention. Methods: The State Inpatient Database (Florida) of the Health Care Utilization Project and the Annual Survey database of the American Hospital Association were linked from 2006 to 2011. Included were patients ≥18 years of age with a primary diagnosis of intestinal obstruction. Patient factors included age, sex, socioeconomic factors, and comorbid conditions. Results: A total of 116,195 patients met our inclusion criteria, and 43,079 underwent operative intervention (37.1%). Patients who required operative correction of the intestinal obstruction after the fifth day of hospitalization, compared with patients who underwent an operation on the day of admission, had increases in mortality (6.1% vs 1.8%, P < .001), complication rates (15.4% vs 4.0%, P < .001), and postoperative hospital stay (9 vs 5 days, P < .001). Patients cared for at a large teaching facility (with surgery residents) had increased odds of early operative intervention by 23% (odds ratio 1.23, [1.20-1.28]), whereas patients at low-volume hospitals had decreased odds of early intervention (odds ratio 0.88, [0.73-0.91]). Conclusion: Initial nonoperative treatment in patients with uncomplicated intestinal obstruction is an important strategy, but the odds of having an adverse event increase as intestinal obstruction is delayed. Importantly, the presence of surgery residents and increasing bed size are hospital characteristics associated with earlier operative intervention, suggesting a quality benefit for care at large teaching hospitals.

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The "weekend effect" in urgent general operative procedures

Zapf MA, Kothari AN, Markossian T, Gupta GN, Blackwell RH, Wai PY, Weber CE, Driver J, Kuo PC

Background: There is growing concern that the quality of inpatient care may differ on weekends versus weekdays. We assessed the "weekend effect" in common urgent general operative procedures. Methods: The Healthcare Cost and Utilization Project Florida State Inpatient Database (2007-2010) was queried to identify inpatient stays with urgent or emergent admissions and surgery on the same day. Included were patients undergoing appendectomy, cholecystectomy for acute cholecystitis, and hernia repair for obstructed/gangrenous hernia. Outcomes included duration of stay, inpatient mortality, hospital-adjusted charges, and postoperative complications. Controlling for hospital and patient characteristics and type of surgery, we used multilevel mixed-effects regression modeling to examine associations between patient outcomes and admissions day (weekend vs weekday). Results: A total of 80,861 same-day surgeries were identified, of which 19,078 (23.6%) occurred during the weekend. Patients operated on during the weekend had greater charges by $185 (P < .05), rates of wound complications (odds ratio [OR] 1.29, 95% confidence interval [95% CI] 1.05-1.58; P < .05), and urinary tract infection (OR 1.39, 95% CI 1.05-1.85; P < .05). Patients undergoing appendectomy had greater rates of transfusion (OR 1.43, 95% CI 1.09-1.87; P = .01), wound complications (OR 1.32, 95% CI 1.04-1.68; P < .05), urinary tract infection (OR 1.76, 95% CI 1.17-2.67; P < .01), and pneumonia (OR 1.41, 95% CI 1.05-1.88; P < .05). Patients undergoing cholecystectomy had a greater duration of stay (P = .001) and greater charges (P = .003). Conclusion: Patients undergoing weekend surgery for common, urgent general operations are at risk for increased postoperative complications, duration of stay, and hospital charges. Because the cause of the "weekend effect" is still unknown, future studies should focus on elucidating the characteristics that may overcome this disparity.

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Postoperative Atrial Fibrillation Predicts Long-Term Cardiovascular Events after Radical Cystectomy.

Blackwell RH, Ellimoottil C, Bajic P, Kothari A, Zapf M, Kliethermes S, Flanigan RC, Quek ML, Kuo PC, Gupta GN

Purpose: Postoperative atrial fibrillation after radical cystectomy occurs in 2% to 8% of cases. Recent evidence suggests that transient postoperative atrial fibrillation leads to future cardiovascular events. The long-term cardiovascular implications of postoperative atrial fibrillation in patients undergoing radical cystectomy are largely unknown. Materials and Methods: The Healthcare Cost and Utilization Project State Inpatient Databases for California and Florida were used to identify patients who underwent radical cystectomy between 2007 and 2010. After excluding patients with a history of atrial fibrillation, coronary artery disease and/or stroke, patients were matched using propensity scoring on age, race, insurance status and preexisting comorbidities. Adjusted Kaplan-Meier time-to-event analysis and Cox proportional hazards models were used to assess the effect of postoperative atrial fibrillation on cardiovascular events (acute myocardial infarction and stroke) during postoperative year 1. Results: Radical cystectomy was performed in 4,345 patients who met the study inclusion criteria, of whom 210 (4.8%) had postoperative atrial fibrillation. There was a significantly higher cumulative incidence of cardiovascular events during the first postoperative year in patients in whom postoperative atrial fibrillation developed (24.8% vs 10.9%, adjusted log rank p=0.007). Cox proportional hazards regression demonstrated an increased risk of cardiovascular events in patients with postoperative atrial fibrillation (HR 10, p=0.02). Conclusion: Our results demonstrate that patients undergoing radical cystectomy in whom transient postoperative atrial fibrillation develops are at significantly increased risk for cardiovascular events in the first postoperative year. Physicians should be vigilant in assessing postoperative atrial fibrillation, even when transient, and establish appropriate followup given the increased risk of cardiovascular morbidity.

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Doing well by doing good: linking access with quality

Chang V, Kuo PC, Wai PY

Background: We hypothesize that medical centers that prioritize altruism can also deliver superior quality care. Methods: Data were obtained from California's Office of Statewide Health Planning and Development, Medicare Hospital Compare, and the Joint Commission US Census Bureau's American Community Survey. Outcomes were measured using summary statistics, regression analysis, and quality indices. Total discounted revenue/total revenue (TDR/TR) served as a proxy for altruistic care. Results: In nonprofit hospitals, TDR/TR positively correlated with 5 quality indices including pneumonia (P < .001), heart failure (P = .05), and overall surgical process of care (P = .009). Hospital size predicted higher quality surgical process (P = .06, 201 to 300 beds; P = .01, >301 beds), hospital teaching status demonstrated positive correlation (β = .048, P = .69), and poverty was negatively correlated (β = -.00072, P = .89). Positive TDR/TR did not adversely affect mortality or readmission rates (P = .52). Conclusions: TDR/TR predicts quality in nonprofit hospitals without increasing mortality and readmission. Altruistic motivation may be associated with the delivery of higher quality surgical care. Keywords: Access; Altruism; Outcomes; Quality; Surgery

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Obesity and trends in malpractice claims for physicians and surgeons

Weber CE, Talbot LJ, Geller JM, Kuo MC, Wai PY, Kuo PC

Background: The increasing prevalence of obesity has altered the practice of medicine and surgery, with the emergence of new operations and medications. We hypothesized that the landscape of medical malpractice claims has also changed. Methods: We queried the Physician Insurers Association of American database for 1990 through 1999 and 2000 through 2009 for cases corresponding to International Classification of Diseases, 9th edition, codes for obesity. We extracted adjudicatory outcome, closed and paid claims data, indemnity payments, primary alleged error codes, National Association of Insurance Commissioners severity of injury class, procedural codes, and medical specialty data. Results: A total of 411 obesity claims were filed from 1990 to 1999 and 1,591 obesity claims were filed from 2000 to 2009. General surgery was the specialty with the greatest number of obesity claims from 1990 to 1999 and was second to family practice for 2000 to 2009. Although the percentage of paid general surgery obesity claims has decreased significantly from 69% in 1990-1999 to 36% in 2000-2009, the mean indemnity payments have increased substantially ($94,000 to $368,000). Conclusion: Recently, the percentage of paid general surgery obesity claims has significantly decreased; however, individual and total indemnity payments have increased. Obesity continues to impact general surgery malpractice substantially. Efforts to manage this component of physician and hospital practices must continue.

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An analytic decision support tool for resident allocation

Talay-Değirmenci I, Holmes CJ, Kuo PC, Jennings OB

Background: Moving residents through an academic residency program is complicated by a number of factors. Across all residency programs the percentage of residents that leave for any reason is between 3.4% and 3.8%.(1) There are a number of residents that participate in research. To avoid discrepancies in the number of residents at the all levels, programs must either limit the number of residents that go into the lab, the number that return to clinical duties, or the number of interns to hire. Traditionally this process consists of random selection and trial and error with names on magnetic strips moved around a board. With the matrix that we have developed this process is optimized and aided by a Microsoft Excel macro (Microsoft Corp, Redmond, Washington). Methods: We suggest that a residency program would have the same number of residents at each residency stage of clinical practice, as well as a steady number of residents at each research stage. The program consists of 2 phases, in the first phase, an Excel sheet called the "Brain Sheet," there are simple formulas that we have prepared to determine the number of interns to recruit, residents in the research phase, and residents that advance to the next stage of training. The second phase of the program, the macro, then takes the list of current resident names along with the residency level they are in, and according to the formulas allocates them to the relevant stages for future years, creating a resident matrix. Results: Our macro for resident allocation would maximize the time of residency program administrators by simplifying the movement of residents through the program. It would also provide a tool for planning the number of new interns to recruit and program expansion. Conclusion: The application of our macro illustrates that analytical techniques can be used to minimize the time spent and avoid the trial and error while planning resident movement in a program.

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Comparing 20 years of national general surgery malpractice claims data: obesity versus morbid obesity

Weber CE1, Talbot LJ, Geller JM, Kuo MC, Wai PY, Kuo PC

Background: We hypothesized that the increasing body mass index of the population has affected general surgery malpractice claims. Methods: We queried the Physician Insurers Association of America database from 1990 to 1999 (ie, period 1) and 2000 to 2009 (ie, period 2) for claims associated with obesity and morbid obesity. We analyzed the error involved, injury severity, procedure, and outcome. Results: Five hundred seventy-five claims were identified. The percentage of paid claims did not differ by body mass index. Improper performance was the most common alleged error, gastric bypass was the most common procedure, and death was the most common injury. For obesity claims, the case was more likely to be settled in period 1 and withdrawn/dismissed in period 2 (P < .001). The number of morbid obesity claims rose from 9 in period 1 to 249 in period 2. Conclusions: The significant rise in morbid obesity claims between periods is likely caused by the substantial increase in the number of bariatric procedures performed.

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Impact of business infrastructure on financial metrics in departments of surgery

Wai PY, O'Hern T, Andersen DO, Kuo MC, Weber CE, Talbot LJ, Kuo PC

Background: In the current environment, pressure is ever increasing to maximize financial performance in surgery departments. Factors such as physician extenders, billing and collection, payor mix, contracting, incentives from the Centers for Medicare and Medicaid Services, and administrative incentives may greatly influence financial performance. However, despite a plethora of information from the University HealthSystem Consortium and the Association of American Medical Colleges, best-practice information for business infrastructure is lacking. To obtain a sampling of current practices, we conducted a survey of departments of surgery. Methods: An anonymous 30-question survey addressing demographics, productivity, revenue and expense profile, payor mix, physician extender and staff personnel, billing and collections methodology, and financial performance was distributed among members of the Society of Surgical Chairs via SurveyMonkey. This was approved by the Loyola Institutional Research Board. Multivariate linear regression analyses and t tests/rank-sum tests were performed, as appropriate. Data are presented as mean ± SEM. Results: A total of 25 (19%) departments responded; 14 were integrated with the hospital/health system, and 11 were integrated with the medical school. In 60% (n = 15), the main hospital had 500 to 1,000 beds; 48% (n = 12) had >4 hospitals in their system. For FY10, MD clinical full-time equivalents (FTEs) were 49 ± 10; total work relative value units (wRVUs) were 320 ± 8 k; and total billed cases were 43 ± 16 k. A total of 23 of 25 used physician-extenders with an average of 18 ± 5 per department and in 22 of 23, the physician extenders billed. On average, there were 18 ± 6 clinical-support staff, 25 ± 11 front-office staff, and 13 ± 3 back-office support staff FTEs. Among these FTEs, there were 16 ± 5 devoted to business operations (billing, coding, denial/claims management, financial oversight). Collections/wRVUs were $60 ± 3 (range, 39-80). Regression modeling demonstrated that total wRVUs were determined by the number of MD FTEs (P = .01), number of physician extenders (P = .01), number of front-office staff (P = .01), number of back-office staff (P = .02), and number of total business staff (P = .01). Collections/wRVUs were predicted by number of hospitals (P = .04), number of MD FTEs (P = .03), number of physician extenders (P = .01), and number of cases/total business staff (P = .02). Interestingly, wRVUs/MD was predicted by number of MD FTEs (P = .01) but were not greatly impacted by numbers of clinical or business support staff. In 4 of 25, the billing and coding staff were incentivized and had a Collections/wRVU = 64 ± 5 whereas nonincentivized staff had collections/wRVU = 59 ± 3. (P = NS) Also, %Accounts receivable >90 days (15% vs 25%) were not substantially different. Only 48% (12/25) have departments have recouped Centers for Medicare and Medicaid dollars for Physician Quality Reporting Initiative, Meaningful Use, Patient-Centered Medical Homes, or other Accountable Care-like programs. One-half (13) of the departments had both an inpatient and outpatient electronic medical record. Finally, on a scale of 1-10 (10 = highest), the average level of satisfaction with billing and collections processes was 6. Conclusion: Our results indicate that the physician extender, clinical support staff, and business staff environment can impact surgeon productivity, and there is opportunity for improvement. Determining best practices for ratios of support staff/MD and optimizing the role of electronic medical record in workflow and billing/collections are critical in the current environment. Our pilot study requires extension across more institutions for validation.

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