Objectives: To compare the long-term benefit of gastric bypass [Roux-en-Y gastric bypass (RYGB)] versus adjustable gastric banding (AGB) on nonalcoholic fatty liver disease (NAFLD) in severely obese patients.
Background: NAFLD improves after weight loss surgery, but no histological study has compared the effects of the various bariatric interventions.
Methods: Participants consisted of 1236 obese patients (body mass index=48.4±7.6 kg/m), enrolled in a prospective longitudinal study for up to 5 years after RYGB (n=681) or AGB (n=555). Liver biopsy samples were available for 1201 patients (97.2% of those at risk) at baseline, 578 patients (47.2%) at 1 year, and 413 patients (68.9%) at 5 years.
Results: At baseline, NAFLD was present in 86% patients and categorized as severe [NAFLD activity score (NAS)≥3] in 22% patients. RYGB patients had a higher body mass index (49.8±8.2 vs 46.8±6.5 kg/m, P<0.001) and more severe NAFLD (NAS: 2.0±1.5 vs 1.7±1.4, P=0.004) than AGB patients. Weight loss at 5 years was 25.5%±11.8% after RYGB versus 21.4%±12.7% after AGB (P<0.001). When analyzed with a mixed model, all NAFLD parameters improved after surgery (P<0.001) and improved significantly more after RYGB than after AGB [steatosis (%): 1 year, 7.9±13.7 vs 17.9±21.5, P<0.001/5 years, 8.7±7.1 vs 14.5±20.8, P<0.05; NAS: 1 year, 0.7±1.0 vs 1.1±1.2, P<0.001/5 years, 0.7±1.2 vs 1.0±1.3, P<0.05]. In multivariate analysis, the superiority of RYGB was primarily but not entirely explained by weight loss.
Conclusions: The improvement of NAFLD was superior after RYGB than after AGB.