Comparison of Liver Fat Indices for the Diagnosis of Hepatic Steatosis and Insulin Resistance

CONTEXT: Hepatic steatosis, defined as increased hepatocellular lipid content (HCL), associates with visceral obesity and glucose intolerance. As exact HCL quantification by (1)H-magnetic resonance spectroscopy ((1)H-MRS) is not generally available, various clinical indices are increasingly used to predict steatosis. OBJECTIVE: The purpose of this study was to test the accuracy of NAFLD liver fat score (NAFLD-LFS), hepatic steatosis index (HSI) and fatty liver index (FLI) against (1)H-MRS and their relationships with insulin sensitivity and secretion. DESIGN, SETTING AND PARTICIPANTS: Ninety-two non-diabetic, predominantly non-obese humans underwent clinical examination, (1)H-MRS and an oral glucose tolerance test (OGTT) to calculate insulin sensitivity and β-cell function. Accuracy of indices was assessed from the area under the receiver operating characteristic curve (AROC). RESULTS: Median HCL was 2.49% (0.62;4.23) and correlated with parameters of glycemia across all subjects. NAFLD-LFS, FLI and HSI yielded AROCs of 0.70, 0.72, and 0.79, respectively, and related positively to HCL, insulin resistance, fasting and post-load β-cell function normalized for insulin resistance. Upon adjustment for age, sex and HCL, regression analysis revealed that NAFLD-LFS, FLI and HSI still independently associated with both insulin sensitivity and β-cell function. CONCLUSION: The tested indices offer modest efficacy to detect steatosis and cannot substitute for fat quantification by (1)H-MRS. However, all indices might serve as surrogate parameters for liver fat content and also as rough clinical estimates of abnormal insulin sensitivity and secretion. Further validation in larger collectives such as epidemiological studies is needed.