Impact of Nonalcoholic Fatty Liver Disease (NAFLD) on Weight Loss After Bariatric Surgery.

OBJECTIVE: Obesity and associated comorbidities, such as NAFLD, impose a major healthcare burden worldwide. Bariatric surgery remains the most successful approach for sustained weight loss and the resolution of obesity-related complications. However, the impact of preexisting NAFLD on weight loss after bariatric surgery has not been previously studied. The goal of this study is to assess the impact of preexisting NAFLD on weight loss outcomes up to 5 years after weight loss surgery. RESEARCH DESIGN AND METHODS: Data from the Michigan Bariatric Surgery Cohort (MI-BASiC) was extracted to examine the effect of baseline NAFLD on weight loss outcomes. The cohort included a total of 714 patients older than 18 years of age undergoing gastric bypass (GB; 380 patients) or sleeve gastrectomy (SG; 334 patients) at the University of Michigan between January 2008 and November 2013. Repeated measure analysis was used to determine if preexisting NAFLD was a predictor of weight loss outcomes up to 5 years post-surgery. RESULTS: We identified 221 patients with an established clinical diagnosis of NAFLD at baseline. Multivariable repeated measure analysis with adjustment for covariates shows that patients with preexisting NAFLD had a significantly lower percentage of total and excess weight loss compared to patients without preexisting NAFLD. Furthermore, our data show that baseline dyslipidemia is an indicator of the persistence of NAFLD after bariatric surgery. CONCLUSIONS: Our data show that patients' body weight loss in response to bariatric surgery is impacted by factors such as preexisting NAFLD. Additionally, we show that NAFLD may persist or recur in a subset of patients after surgery, and thus careful continued follow-up is recommended.