Predictors of nonalcoholic steatohepatitis and advanced fibrosis in morbidly obese patients

Background: Nonalcoholic fatty liver disease (NAFLD) is a common form of chronic liver disease in the United States. It is commonly associated with the components of the metabolic syndrome including obesity. From the spectrum of NAFLD, only patients with nonalcoholic steatohepatitis (NASH) have been convincingly shown to have a potential for progression to cirrhosis. We report the prevalence of NAFLD and NASH as well as predictors of NASH and advanced fibrosis in morbidly obese patients. Methods: 212 consecutive patients who underwent bariatric surgery were enrolled in the study. A liver biopsy was performed at the time of the surgery. Causes of chronic liver disease other than NAFLD were excluded by clinical and laboratory evaluation. Results: The prevalence of NAFLD was 93%. Of those with NAFLD, 26% had NASH. 17 patients (9%) had advanced fibrosis (i.e., bridging fibrosis or cirrhosis). Male gender, AST, and type 2 diabetes mellitus were independently associated with NASH. Waist-to-hip ratio, AST, and focal hepatocyte necrosis on liver biopsy were independently associated with advanced fibrosis. Interestingly, while AST was associated with NASH and advanced fibrosis, the majority of the patients with either NASH or advanced fibrosis had normal AST. Conclusions: NAFLD and NASH are very common in morbidly obese patients undergoing bariatric surgery. Features associated with the metabolic syndrome and liver cell injury are independently associated with either NASH or advanced fibrosis.