S3153 Comparative Risk of Infectious and Biliary Complications Following Gastric Bypass versus Sleeve Gastrectomy: A Propensity-Matched Analysis

Introduction: With obesity rates rising, bariatric surgery remains one of the most effective strategies for long-term weight loss and metabolic improvement. Among the most common procedures, gastric bypass and sleeve gastrectomy (SG) have distinct anatomical changes that may influence postoperative risks. Notably, gastric bypass may increase susceptibility to infectious and biliary complications due to altered gut anatomy and bile flow. This study compared the 1-year incidence of severe sepsis, acute respiratory distress syndrome (ARDS), and biliary complications between gastric bypass and SG using a large, real-world electronic health record network. Methods: We utilized the TriNetX Global Collaborative Network to conduct a retrospective cohort analysis evaluating infectious complications among patients undergoing gastric bypass (cohort 1) and sleeve gastrectomy (cohort 2). Propensity score matching (1:1) was applied using a greedy nearest-neighbor algorithm with a 0.1 caliper. Matching variables included age, sex, race, and comorbidities such as type 2 diabetes, metabolic syndrome, hypertension, obesity, chronic kidney disease, nicotine dependence, and alcohol use. Outcomes assessed over a 1-year period included mortality, choledocholithiasis, cholangitis, severe sepsis without shock, septic shock, and ARDS. Odds ratios (OR) with 95% confidence intervals (CI) were calculated. Results: After matching (n = 81,333/group), gastric bypass was associated with increased odds of severe sepsis without shock (OR 1.77; CI 1.40-2.24), septic shock (OR 2.01; CI 1.61-2.51), ARDS (OR 2.11; CI 1.34-3.34), choledocholithiasis (OR 1.24; CI 1.08-1.43), cholangitis (OR 2.26; CI 1.39-3.70), and mortality (OR 2.29; CI 1.94-2.71) compared to SG. Conclusion: Gastric bypass is associated with a significantly higher risk of infectious and biliary complications—including sepsis, ARDS, cholangitis, and mortality—compared to sleeve gastrectomy. These risks may reflect disruptions to bile flow and gut integrity. The elevated mortality rate underscores the importance of thoughtful patient selection, proactive perioperative planning, and close postoperative monitoring. While bypass remains a powerful metabolic tool, its complication profile supports the need for risk stratification and long-term surveillance to improve outcomes.