Hepatic histology in obese patients undergoing bariatric surgery.

BACKGROUND/AIMS: Obesity is one of the most important clinical associations with non-alcoholic steatohepatitis (NASH). Our aim was to assess the prevalence of non-alcoholic fatty liver disease (NAFLD)/NASH in morbidly obese patients and the risk factors to more aggressive liver disease in this population.
METHODS: Review of available studies on prevalence of NAFLD/NASH in severely obese patients submitted to bariatric surgery.
RESULTS: Twelve observational and transversal studies were included, with consecutive recruitment, and prospective evaluation of data, summing 1620 patients with severe obesity. Prevalence of steatosis and NASH was 91% (range: 85-98%) and 37% (24-98%), respectively, with unexpected cirrhosis in 1.7% (1-7%). NASH was not related with age or body mass index, but there was an association between male sex and NASH/hepatic fibrosis. Diabetes mellitus and insulin resistance were the conditions most frequently associated with NASH, and hypertension with advanced hepatic fibrosis.
CONCLUSIONS: There is a very high prevalence of NAFLD in asymptomatic morbidly obese patients, more than one-third presenting histological criteria for NASH. This review underscores the large variations in prevalence of NASH between studies, calling for the need for a better agreement in the use of the histological criteria.