Non-invasive predictors of prognosis of Asian patients with histopathologically-confirmed lean nonalcoholic fatty liver disease

BACKGROUND: The prognostic factors of morbidity and mortality in patients with lean NAFLD (body mass index < 25.0 kg/m(2)) are unknown. METHODS: In this retrospective study, 446 Japanese patients with histopathologically-confirmed NAFLD (lean NAFLD, n = 170) were followed for liver events, cardiovascular events, type 2 diabetes mellitus, and non-liver malignancies. The median observation period was 4.6 years. We also investigated the predictors of severe fibrosis (stage 3–4) and mortality in lean NAFLD patients. RESULTS: Glycolipid metabolic markers, liver function tests, NAFLD fibrosis score (NFS), and histological scoring were significantly lower in lean NAFLD patients than in non-lean NAFLD. The incidence of liver cancer was higher while that of T2DM was lower in lean NAFLD. Kaplan–Meier analysis showed no significant difference in overall survival between the lean and non-lean NAFLD. Multivariate analysis of data of lean NAFLD identified NFS ≥ − 1.455 as significant independent predictor of severe fibrosis, while history of liver cancer and NFS ≥ − 1.455 were predictors of overall survival. CONCLUSIONS: Although patients with lean NAFLD have better histopathological and biochemical profile compared to patients with non-lean NAFLD, the prognosis is not different between the two groups. Lean NAFLD patients with NFS ≥ − 1.455 or history of liver cancer should be monitored carefully during follow-up.