Biliopancreatic Limb Length Impacts Metabolic Dysfunction-Associated Steatotic Liver Disease Trajectories After Roux-En-Y Gastric Bypass

Objective To assess whether biliopancreatic limb (BPL) length in Roux-en-Y gastric bypass (RYGB) affects improvement in metabolic dysfunction-associated steatotic liver disease (MASLD). Setting University Hospital Center. Methods We conducted a retrospective cohort study of adults undergoing RYGB between 2019-2024. Patients were dichotomized a priori by BPL length: ≈ 70 cm (short) versus ≥ 100 cm (long). Outcomes were evaluated at baseline, 3 months (3M), 1 year (1Y) and 2 years (2Y) postoperatively. Primary outcomes were MASLD-related non-invasive tests (NITs) including the NAFLD Fibrosis Score (NFS) and NI-NASH detection score (NI-NASH DS). Results Compared with short BPL, long BPL was associated with lower NI-NASH DS at 3M (-1.19; 95% CI : -1.93 to -0.48; q < 0.01) and 1Y (-0.77; 95% CI : -1.37 to -0.15 q < 0.05), and lower NFS at 1Y (-0.39; 95% CI : -0.70 to -0.09; q < 0.05) and 2Y (-0.53; 95% CI : -0.96 to -0.10; q <0.05). HbA1c was lower at 1Y (-0.10; 95% CI : -0.20 to 0.00; q < 0.05) and 2Y (-0.20; 95% CI : -0.30 to -0.00; q < 0.05), while total weight loss was similar. Total cholesterol and LDL-cholesterol were lower at 1Y and 2Y. Nutritional markers were largely comparable. Conclusion A longer BPL (≥ 100 cm) was associated with greater improvements in MASLD-related NIT trajectories at 1Y and 2Y after RYBG, with better glycemic control and similar weight loss, without evidence of nutritional deficiency.