Effect of Roux-en-Y gastric bypass and sleeve gastrectomy on nonalcoholic fatty liver disease: a comparative study.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in the United States; 85%-95% of the morbidly obese population have NAFLD and 33% have nonalcoholic steatohepatitis. There is a lack of comparative data assessing various bariatric procedures and their effect on NAFLD.

OBJECTIVES: To assess and compare the effects of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) on NAFLD.

SETTING: Academic Center, United States

METHODS: All bariatric cases performed at the authors' institution (an academic center in the United States) between 2005 and 2012 that had both intraoperative and postoperative liver biopsies were included. NAFLD Activity Score (NAS) and fibrosis stages were used to evaluate improvement in liver histology.

RESULTS: Fourteen RYGB and 9 SG patients with liver biopsies were identified. 57% and 73% in each group were female, respectively. P = .2. RYGB patients were older (56.2 ± 8.6 versus 46.3 ± 11.7; P<.05), and had lower initial body mass index (BMI) and higher NAS (51.0 ± 13.0 kg/m(2) versus 72.7 ± 21.0 kg/m(2); P<.05) and (4.4 ± 1.7 versus 2.6 ± 1.6; P<.05), respectively. Prevalence of co-morbidities was comparable between groups. After a mean follow-up of 1.5 years, weight loss percentage was 32% ± 11.8% and 25% ± 6.8% after RYGB and SG, respectively (P value not significant). Percentage of excess weight loss was higher in RYGB patients (69.8% ± 27% versus 37.2% ± 12.3%; P<.05). NAS after RYGB significantly improved in all morphologic characteristics, whereas only steatosis and total NAS improved after SG. Fibrosis state improved in both groups but to a greater degree after RYGB (2.5 ± 1.3 versus .3 ± .6; P< .05).

CONCLUSIONS: There were no significant differences in NAS score decrease after RYGB and SG procedures, although the baseline characteristics of the groups differ. This exploratory data supports the idea of conducting a randomized trial to determine the differential effects of SG and RYGB on NAFLD.