A community-based study on the application of fatty liver index in screening subjects with nonalcoholic fatty liver disease

Background/Purpose: Nonalcoholic fatty liver disease (NAFLD) is now a global liver disease. The fatty liver index (FLI), which is calculated by the equation comprising waist circumference, body mass index (BMI), triglyceride, and gamma glutamyl transpeptidase (GGT), is frequently used for hepatic steatosis evaluation. This study aimed to evaluate the optimal cut-off point of FLI to select subjects for abdominal ultrasonography (US) screening for NAFLD in the community. Methods: From August 2013 to August 2016, a community-based study was performed in the northeastern region of Taiwan. All subjects participated in a demographic survey, blood testing, and abdominal US. The formula for FLI is: FLI = [e ^{0.953×loge (TG)+0.139×BMI+0.718×loge (GGT) +0.053×waist circumference−15.745}]/[1 + e ^{0.953×loge (TG)+0.139×BMI+0.718×loge (GGT)+0.053×waist circumference−15.745}] × 100. Results: A total of 1371 subjects were included (746 in NAFLD group and 625 in the control group). The mean ages were 57.1 years in the control group and 56.3 years in the NAFLD group. The optimal cut-off points of FLI to discriminate fatty liver by abdominal US were 20 in male and 10 in female (sensitivity 80.3% and 76.1%; specificity 66.9% and 65.5%, respectively). FLI was correlated with the severity of fatty liver by abdominal US, predict fat component percent and NAFLD fibrosis score, especially in the female subjects. Conclusion: FLI could be a tool to select subjects for abdominal US in a large community survey. The cut-off point of FLI might be set to 10 for female and 20 for male subjects, to increase the sensitivity for selecting subjects to receive abdominal US.