Predictors of Liver Fat and Stiffness in Non-Alcoholic Fatty Liver Disease (NAFLD) - an 11-Year Prospective Study

Liver fat can be non-invasively measured by proton magnetic resonance spectroscopy (H-1-MRS) and fibrosis estimated as stiffness using transient elastography (FibroScan). There are no longitudinal data on changes in liver fat in Europids or on predictors of liver stiffness using these methods. We determined liver fat (1H-MRS) and clinical characteristics including features of insulin resistance at baseline and after a median follow-up period of 11.3 (range 7.3-13.4) years in 97 Finnish subjects. Liver stiffness was measured at 11.3 years. Liver fat content decreased by 5% (p < 0.05) over time. Values at baseline and 11.3 years were closely interrelated (r = 0.81, p < 0.001). Baseline liver fat (OR 1.32; 95% CI: 1.15-1.50) and change in BMI (OR 1.67; 95% CI: 1.24-2.25) were independent predictors of liver fat at 11.3 years (AUROC 0.90; 95% CI: 0.83-0.96). Baseline liver fat (AUROC 0.84; 95% CI: 0.76-0.92) predicted liver fat at 11.3 years more accurately than routinely available parameters (AUROC 0.76; 95% CI: 0.65-0.86, p = 0.02). At 11.3 years, 29% of the subjects had increased liver stiffness. Baseline liver fat (OR 2.17; 95% CI: 1.05-4.46) was an independent predictor of increased liver stiffness. These data show that liver fat is more important than the associated metabolic abnormalities as the predictor of future liver fat and fibrosis.