Useful parameters for distinguishing nonalcoholic steatohepatitis with mild steatosis from cryptogenic chronic hepatitis in the Japanese population

Background/Aims: As detecting mild steatosis is difficult by abdominal ultrasonography (US), nonalcoholic steatohepatitis (NASH) with mild steatosis may sometimes be confused with cryptogenic chronic hepatitis. We aimed to test this possibility and to isolate factors that may indicate NASH. Methods: First, 53 Japanese patients diagnosed as having cryptogenic chronic hepatitis by laboratory examination and US were enrolled. These patients were histologically divided into NASH and non-NASH groups, and their clinical features were compared. Second, the diagnostic accuracy of predictors of NASH was examined prospectively. Results: Fifteen patients (28%) were histologically diagnosed as having NASH with mild steatosis. Multivariable analysis revealed that body mass index (BMI) and serum ferritin level were independent predictors of NASH. The best cutoff values to detect NASH were assessed by using receiver-operating characteristic curves: BMI > 25.2 kg/m(2) and serum ferritin level > 142 ng/ml. When both markers were concomitantly negative, the negative predictive value to detect NASH was 100%. Conclusions: In cases of mild steatosis, US is not a perfect tool for the accurate diagnosis of NASH. BMI and serum ferritin level are useful discriminators of NASH from cryptogenic chronic hepatitis, and might be helpful markers for diagnosing NASH more accurately in Japanese patients.