Nonalcoholic fatty liver disease (NAFLD) is common in severely obese subjects and can progress to cirrhosis and liver failure. Predicting advanced or progressive disease may help in selecting patients for liver biopsy and assist the development of therapeutic options.

Liver biopsies were taken at laparoscopic obesity surgery in 105 consecutive patients. The clinical and biochemical variables were analyzed for correlation with specific histologic features.

Twenty-six patients (25%) were found to have nonalcoholic steatohepatitis (NASH), and 11 (42%) of these had advanced fibrosis. A raised index of insulin resistance (odds ratio [OR] 9.3, 95% confidence interval [CI] 3.4–26), systemic hypertension (OR 5.2, 95% Cl 2.0–13.5), and raised alanine aminotransferase (OR 8.6, 95% Cl 3.1–23.5) were independent predictors of NASH. A combination of 2 or 3 of these predictors allows a sensitivity of 0.8 and specificity of 0.89 for NASH. Alcohol consumption was associated with a reduction in NASH (OR 0.35, 95% Cl 0.12–1.00) and diabetes (OR 0.18, 95% Cl 0.047–0.67).

Insulin resistance and systemic hypertension, features of the metabolic syndrome, are independently associated with advanced forms of NAFLD. Moderate alcohol consumption seems to reduce the risk of NAFLD in the severely obese, possibly by reducing insulin resistance.