Roux-en-Y gastric bypass versus adjustable gastric banding to reduce nonalcoholic fatty liver disease: a 5-year controlled longitudinal study.

Abstract

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. NAFLD improves after weight loss surgery, but no histological study has compared the effects of the various bariatric interventions. 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. 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. The improvement of NAFLD was superior after RYGB than after AGB.