S2349 Impact of Bariatric Surgery Type on Mortality and Liver Outcomes in Morbidly Obese Patients With NAFLD: A Propensity Score-Matched Cohort Study

Introduction: The role of bariatric surgery in improving outcomes among patients with nonalcoholic fatty liver disease (NAFLD) remains an area of active investigation. While both sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) improve metabolic parameters, comparative risks of hepatic and all-cause complications are not well established. This study assessed mortality and hepatic fibrosis-related outcomes among matched cohorts undergoing SG or RYGB. Methods: Adult patients (≥18 years) with body mass index (BMI) ≥35 kg/m² and a diagnosis of NAFLD or nonalcoholic steatohepatitis (NASH) were identified. Two cohorts—RYGB and sleeve gastrectomy—were formed based on procedure codes. Propensity score matching (1:1) was applied to balance demographic and clinical variables, yielding 13,566 patients in each group. Primary outcomes included liver-related complications and all-cause mortality. Odds ratios (ORs), 95% confidence intervals (CIs), and P-values were reported. Results: After propensity score matching, 13,566 patients were included in each group. The overall cohort's mean ± SD age was 45.1 ± 11.4 years for the RYGB group and 45.3 ± 11.7 years for the sleeve group, with 77.1% and 77.0% woman, respectively. The majority of patients were White (74.9% in the RYGB group vs 74.9% in the sleeve group) and not Hispanic or Latino (67.4% vs 66.0%). Matching achieved balance across cohorts (standardized difference <0.01). The risk of liver-related complications was significantly lower in the RYGB group compared to the sleeve group (9.7% vs 10.9%; OR: 0.876, 95% CI: 0.81–0.947; P = 0.0009). However, mortality was significantly higher in the RYGB group than in the sleeve group (5.6% vs 3.3%; OR: 1.7, 95% CI: 1.509–1.914; P < 0.0001). Conclusion: Among morbidly obese patients with NAFLD, RYGB was associated with a modest reduction in liver-related complications compared to SG, but at the cost of significantly increased all-cause mortality. These findings highlight the importance of individualized risk-benefit analysis when selecting a bariatric procedure in patients with metabolic liver disease.