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

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.

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

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.

Survival Tree Provides Individualized Estimates of Survival After Lung Transplant.

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) were queried for single and double lung transplants in adult patients. Graft survival time <7 d 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 10-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 (8175 single; 19,121 double lung) 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 preoperative and postoperative factors influence survival after lung transplantation. Thus, preoperative patient counseling should acknowledge a degree of uncertainty given the influence of postoperative factors.

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

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.

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

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.

The Effects of Clopidogrel Duration on Carotid Artery In-Stent Restenosis.

BACKGROUND: There are limited data supporting a specific duration for dual antiplatelet therapy in carotid artery stenting (CAS), and most clinical evidence is derived from studies involving coronary interventions. As a result, the appropriate duration of dual antiplatelet therapy after CAS is yet to be determined. We aimed to elucidate whether the duration of dual antiplatelet therapy played a role in the rate of carotid in-stent restenosis. METHODS: A retrospective analysis of all patients who underwent CAS at our institution over a 20-year period (1996-2016) was performed (n = 279). Patients who did not complete their follow-up duplex studies or were not discharged on clopidogrel were excluded from the study. Patients were separated into short-term (<6 weeks, n = 159) and long-term (>6 weeks, n = 112) clopidogrel users based on duration of therapy. We defined clinically significant in-stent restenosis as >50% restenosis (peak systolic velocity = 224 cm/s) in symptomatic patients and >80% restenosis (peak systolic velocity = 325 cm/s) in asymptomatic patients status-post prior CAS based on published velocity criteria. Rates of in-stent restenosis at 1-year, 2-year, and 5-year intervals were analyzed between the 2 groups using chi-squared analysis. RESULTS: Demographic information was largely similar between the 2 groups; however, short-term clopidogrel users were more likely to have a history of atrial fibrillation (9.43% vs. 1.68%, P = 0.008) and were less likely to have a history of coronary artery bypass graft (16.35% vs. 29.41%, P = 0.009), diabetes (33.34% vs. 49.58%, P = 0.006), and coronary artery disease (50.31% vs. 63.03%, P = 0.035). All patients were on long-term aspirin therapy. There was no significant difference between overall rates of in-stent restenosis between the short-term and long-term clopidogrel users (5.03% vs. 9.24%, P = 0.168) within 5 years of the index procedure. Similar results were observed when these groups were evaluated at 1-year (5.61% vs. 3%, P = 0.321), 2-year (2.02% vs. 6.59%, P = 0.072), and 5-year (2.24% vs. 3.57%, P = 0.635) follow-up. CONCLUSIONS: No statistically significant difference was observed in the rate of in-stent restenosis after CAS between short-term and long-term clopidogrel therapy. Patients in whom there is no other indication for longer duration clopidogrel therapy may be considered for shorter duration course of dual antiplatelet therapy following CAS.

Examining surgeon stress in robotic and laparoscopic surgery.

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.

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

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. 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. 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). 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.

Is nonoperative management of appendicitis inferior in the COVID-19 era?

BACKGROUND: Previous studies on nonoperative management (NOM) of acute appendicitis (AA) 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 nonoperative and operative management groups, regardless of COVID-19 status. METHODS: We queried the National COVID Cohort Collaborative from 2020 to 2023 to identify adults with AA who underwent operative or NOM. COVID-19 status was denoted as follows: COVID-negative, COVID-active, or COVID-recovered. Intention to treat was used for NOM. 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 NOM between COVID groups. Adjusted analysis indicated, compared with operative, NOM carried higher odds of mortality and readmission for COVID-negative and COVID-active patients. CONCLUSION: This study demonstrates higher odds of mortality among NOM of appendicitis and near equivalent outcomes for operative management regardless of COVID-19 status. We conclude that NOM of appendicitis is associated with worse outcomes for COVID-active and COVID-negative patients. In addition, we conclude that a positive COVID test or recent COVID-19 illness alone should not preclude a patient from appendectomy for AA. Surgeon clinical judgment of a patient's physiology and surgical risk should, of course, inform the decision to proceed to the operating room. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level III.

Artificial Intelligence in Surgical Research: Accomplishments and Future Directions.

MINI-ABSTRACT: 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. OBJECTIVE: 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.

Corrigendum to "Association of state-level factors with rate of firearm-related deaths" [Surg. Open Sci. vol. 14 (2023) 114-119].

[This corrects the article DOI: 10.1016/j.sopen.2023.07.011.].

Patient outcomes and cost in robotic emergency general surgery.

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). 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. 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. 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.

Interpretable machine learning accurately reclassifies lobectomy surgical approaches by cost.

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.

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

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.

Machine Learning Analysis of Postlaparoscopy Hernias and "I'm Leaving You to Close" Strategy.

INTRODUCTION: Contributing factors to postlaparoscopy hernia are unknown. We hypothesized that postlaparoscopy 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) wereused to track 1-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 was identified using CPT and ICD-10. Propensity matching and eight machine learning modes were utilized including logistic regression, neural network, gradient boosting machine, random forest, gradient boosted trees, classification and regression trees, k nearest neighbors and support vector machines. 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 d (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 postlaparoscopy hernias. Performance of laparoscopic cholecystectomy at teaching hospitals is not associated with increased postoperative hernias.

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

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.

Causal analysis of socioeconomic influence on cost of care: The emergency general surgery model.

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.

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

BACKGROUND: Elucidating contributors affecting liver transplant survival is paramount. Current methods offer crude global group outcomes. To refine patient-specific mortality probability estimation and to determine covariate interaction using recipient and donor data, we generated a survival tree algorithm, Recipient Survival After Orthotopic Liver Transplantation (ReSOLT), using United Network Organ Sharing (UNOS) transplant data. STUDY DESIGN: The UNOS database was queried for liver transplants in patients ≥18 years old between 2000 and 2021. Preoperative factors were evaluated with stepwise logistic regression; 43 significant factors were used in survival tree modeling. Graft survival of <7 days was excluded. The data were split into training and testing sets and further validated with 10-fold cross-validation. Survival tree pruning and model selection was achieved based on Akaike information criterion 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 (area under the curve = 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 5- and 10-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.