Prevalence and predictive factors of non-alcoholic steatohepatitis (NASH) in morbidly obese patients undergoing bariatric surgery

Background: In patients with morbid obesity selected for bariatric surgery, previous studies have shown a prevalence of NASH varying from 2.6% to 91%. The prevalence of NASH and extensive fibrosis were studied in a prospective cohort of patients with morbid obesity requiring bariatric surgery, to identify predictive factors of NASH. Methods: From July 01 to Sept 02, every patient requiring bariatric surgery had a liver biopsy. The diagnosis of NASH was established using Lee's criteria. Results: 92 patients (85 women, age 38 +/- SEM 11 years) were analyzed. Mean BMI was 45.7 +/- 5.1 kg/m(2). 35 patients had lobular inflammation. 9 patients had steatosis associated with lobular necrotic and inflammatory foci and ballooning degeneration or pericellular fibrosis. No cirrhosis or extensive fibrosis was evidenced. The prevalence of NASH in this population was 9.8%. Waist/hips ratio and BMI were independent predictors of lobular inflammation, but only BMI was an independent factor of NASH in multivariate analysis. Conclusion: In this prospective cohort of patients at bariatric surgery, the prevalence of NASH was 9.8%. BMI was the only predictive factor for NASH.