Noninvasive Estimation of Disease Activity and Liver Fibrosis in Nonalcoholic Fatty Liver Disease Using Anthropometric and Biochemical Characteristics, Including Insulin, Insulin Resistance, and 13C-Methionine Breath Test

Abstract

ObjectiveThe purpose of this study was to noninvasively estimate disease activity and liver fibrosis in patients with nonalcoholic fatty liver disease (NAFLD) using anthropometric and biochemical characteristics and the C-13-methionine breath test (MeBT).MethodsA total of 164 patients with histologically proven NAFLD and 56 healthy controls were included in the study. Anthropometric and biochemical analyses and the MeBT were performed on all patients and controls.ResultsBMI; waist circumference; waist-hip ratio; transaminase, lipid, -glutamyl transpeptidase (GGT), glucose, and insulin levels; and insulin resistance were significantly higher in patients with NAFLD than in controls. The GGT level and the MeBT were independent predictors of nonalcoholic steatohepatitis (NASH). Fibrosis was correlated with GGT, bilirubin, cholesterol, and insulin levels, and the MeBT, but the test was the only independent predictor of significant fibrosis. Patients with simple steatosis had similar MeBT values as controls. The MeBT values were significantly lower in NASH and NASH-cirrhosis patients (P<0.001) compared with simple steatosis patients and controls. Patients with advanced fibrosis (F2-3) had significantly lower MeBT values than patients with mild fibrosis (F0-1; P<0.001). The area under the receiving operating characteristic curve for NASH and advanced fibrosis was estimated to be 0.95 in the total cohort.ConclusionThis study indicates that anthropometric and biochemical parameters are insufficient for estimating the presence of NASH or the fibrosis stage. However, the MeBT is a suitable noninvasive method for accurately predicting which patients suffer from simple steatosis, NASH, or NASH-cirrhosis.