Validation of simple indexes for nonalcoholic fatty liver disease in western China: a retrospective cross-sectional study

Various noninvasive algorithms have been developed for predicting the presence of nonalcoholic fatty liver disease (NAFLD). The evaluation of the indexes' diagnostic performance has been reported in Europe and Asia over the past decade; however, external validation of them in China is rare. This study was aimed to evaluate various indexes for NAFLD in western China. It was a retrospective cross-sectional study, using data from a large-scale health check-up project at Sichuan provincial hospital. Receiver operating characteristic (ROC) curves of eight indexes, including the fatty liver index (FLI), the hepatic steatosis index, lipid accumulation product and etc., were developed to predict ultrasonographic NAFLD. There were 13,122 subjects in this study (2,692 NAFLD patients and 10,430 non-NAFLD participants). The area under ROC curve of FLI for predicting NAFLD was 0.880 (95% confidence interval, 0.874-0.886), which was significantly higher than other seven indexes. Accuracy, sensitivity and specificity of FLI for NAFLD were good (cut-off value = 30, 0.782, 0.832, 0.770 and cut-off value = 60, 0.838, 0.443, 0.940, respectively). Furthermore, FLI also presented advantages in expenditure and accessibility, compared with other indexes. It supports FLI as an easily accessible index for physicians and a reliable predictor for NAFLD screening in western China.