Different predictors of steatosis and fibrosis severity among lean, overweight and obese patients with nonalcoholic fatty liver disease

Abstract

Backgrounds: Non-obese nonalcoholic fatty liver disease (NAFLD) is paradoxically associated with improved metabolic and pathological features at diagnosis but worse prognosis relative to obese NAFLD.

Aim: To compare predictors of disease severity in NAFLD with different body mass index (BMI) categories.

Methods: All 1509 consecutive NAFLD patients were classified as lean (20.2%), overweight (23.1%) and obese (56.7%). Liver fat content (LFC) and fibrosis were estimated with magnetic resonance imaging-based proton density fat fraction and shear wave elastography respectively.

Results: Lipid profiles and uric acid (UA) were significantly increased in parallel with BMI categories (pairwise comparison P < 0.001), but insulin resistance (IR) was significantly different between the non-obese and obese groups. For LFC ≥ 10%, increased waist circumference (WC) was an independent predictor in all groups, while UA elevation (P = 0.02) was predictive in the overweight patients, but BMI ≥ 28 kg/m² (P = 0.029) and IR (P = 0.026) were significant in the obese patients. For fibrosis, alanine aminotransferase (ALT) > 40 U/L (P = 0.031), increased WC (P = 0.012) and BMI ≥ 28 kg/m² (P < 0.001) plus ALT > 40 U/L (P = 0.007) were predictors in the lean, overweight and obese patients, respectively.

Conclusions: WC was strongly predictive of disease severity in all NAFLD, while UA and BMI plus IR were additional predictors in the overweight and obese NAFLD respectively. Individualized screening strategies should be established for NAFLD according to different BMIs.

Keywords: Body mass index; Liver fat content; Liver fibrosis; Waist circumference.