NAFLD in clinical practice : Can simple blood and anthropometric markers be used to detect change in liver fat measured by 1H-MRS?

Background & Aims: Research in NAFLD management is commonly based on quantitative assessment of liver fat by proton-magnetic resonance spectroscopy (1H-MRS), and translation of this into clinical practice is currently limited by availability and expense. Novel steatosis biomarkers have been proposed for the prediction of liver fatness; however, whether these are suitable for detecting changes in liver fat is unknown. We aimed to determine the accuracy of these indices, and waist circumference (WC), in quantifying longitudinal change in 1H-MRS-quantified liver fat. Methods: We performed a secondary analysis using data from 97 overweight/obese adults (age: 39.7±11.5 years, body mass index: 30.7±4.4 kg/m2, liver fat: 6.0±4.8%, 65% male) who completed either an 8-week exercise or 12-week nutraceutical intervention, with varying degrees of change in liver fat. Baseline and post-intervention measures were liver fat (1H-MRS), NAFLD Liver Fat Score, Liver Fat Equation (LFE), Fatty Liver Index (FLI), Hepatic Steatosis Index (HSI), the Visceral Adiposity Index (VAI) and WC. Results: Only the change in HSI, FLI and WC was associated with change in liver fat; however, correlations were weak to moderate. There was no agreement between the LFE and 1H-MRS for detecting liver fat change. Only change in WC significantly affected change in liver fat (P<.001), and WC AUROC for the presence of steatosis was 0.65 and 0.78 for men and women respectively.Conclusions: Novel indices are limited in their ability to detect longitudinal change in liver fat. Waist circumference may offer modest utility as a surrogate to infer liver fat change with lifestyle interventions