Biliopancreatic limb length in one-anastomosis gastric bypass: weight-loss outcomes in a BMI-tailored observational cohort

Abstract Background The optimal biliopancreatic limb (BPL) length in one-anastomosis gastric bypass (OAGB) remains controversial. Because BPL length is frequently tailored to baseline patient characteristics, observational comparisons may be confounded by patient selection. We evaluated whether BPL length independently influenced long-term outcomes after adjustment for baseline obesity severity. Methods This retrospective single-center cohort included 147 consecutive patients undergoing primary OAGB between 2019 and 2022. According to an institutional BMI-tailored strategy, patients received a 150-cm (n = 46), 180-cm (n = 52) or 200-cm (n = 49) BPL. The primary endpoint was percentage total weight loss (%TWL) at 36 months. Multivariable analyses adjusted for baseline BMI. Results Baseline BMI differed significantly among groups. Although crude analyses showed significant differences in 36-month %TWL, BPL length was no longer independently associated with weight loss after BMI adjustment, whereas baseline BMI remained an independent predictor. Anemia rates were similar across groups, while hypoalbuminemia occurred numerically more frequently after a 200-cm BPL. Smoking independently predicted marginal ulcer. Conclusions Within a BMI-tailored OAGB strategy, extending the BPL beyond 180 cm did not improve long-term weight loss after adjustment for baseline BMI. These findings suggest that observational comparisons of BPL length should account for patient allocation and support individualized BPL selection until high-quality prospective evidence becomes available.