S2209 Adverse Events and Mortality Following Endoscopic Retrograde Cholangiopancreatography (ERCP) in Underweight Individuals: A Multicenter Propensity Score-Matched Study

Introduction: While patient-related factors such as obesity have been widely studied in relation to ERCP-associated complications, the impact of low body mass index (LBMI) remains underexplored. Patients with LBMI may have altered physiology, nutritional deficiencies, or frailty, potentially increasing their risk for adverse events (AEs). Understanding this risk is essential for optimizing procedural outcomes in this cohort. Methods: We conducted a retrospective cohort study using the TriNetX multi-institutional database to evaluate ERCP-related AEs in patients with LBMI (<18.4 kg/m²) compared to nonobese controls (BMI 18.5–29.9 kg/m²). Primary outcomes included 7-day incidence of gastrointestinal bleeding, perforation, cholangitis, pancreatitis, and aspiration pneumonia, and 30-day rates of sepsis and all-cause mortality. One-to-one propensity score matching was performed to adjust for baseline demographic and comorbidities. Risks were reported as adjusted odds ratios (aORs) with 95% confidence intervals (CIs). Results: A total of 6,517 LBMI patients underwent ERCP. After matching, baseline characteristics were well balanced. LBMI was associated with a significantly increased risk of blood transfusion within 7 days (aOR: 1.471; 95% CI: 1.173–1.845). A trend toward increased aspiration pneumonia was observed (aOR: 1.656; 95% CI: 0.986–2.783), though not statistically significant. No significant differences were found in gastrointestinal bleeding (aOR: 1.037; 95% CI: 0.796–1.353), perforation (aOR: 1.144; 95% CI: 0.815–1.608), cholangitis (aOR: 1.067; 95% CI: 0.960–1.185), pancreatitis (aOR: 0.971; 95% CI: 0.878–1.074), or ICU admission (aOR: 0.970; 95% CI: 0.824–1.141). At 30 days, LBMI was linked to a significantly higher risk of all-cause mortality (aOR: 1.401; 95% CI: 1.177–1.667). Sepsis risk was not significantly different (aOR: 1.086; 95% CI: 0.971–1.214). Conclusion: LBMI was independently associated with higher odds of 7-day blood transfusion and 30-day all-cause mortality following ERCP. Although other AEs such as aspiration pneumonia and sepsis showed numerical increases, these did not reach significance. These findings highlight the need for careful risk assessment and peri-procedural planning in underweight patients undergoing ERCP.