Abstract: Objective The aim of this study was to investigate the efficacy of triglyceride glucose index (TyG)in predicting severity of patients with non-alcoholic fatty liver diseases(NAFLD). Methods 44913 individuals who participated in health examinations at the Health Management Center, Hunan Provincial People's Hospital between January 2020 and December 2022 were enrolled. The diagnosis of NAFLD was made by ultrasonography, and the TyG index was calculated according to literature report. The univariate and multivariate Logistic regression analysis were applied to reveal the risk factors, and the area under receiver operating characteristic curve(AUC) was used to predict the diagnostic efficacy. Results Out of our 44913 participants, there were 15901 patients (35.4%) with NAFLD confirmed; the age, BMI, systolic blood pressure, diastolic blood pressure, serum triglyceride(TG), low density cholesterol(LDL-C), total cholesterol(TC), fasting plasma glucose(FPG), ALT levels and TyG index in patients with NAFLD were(45.9±13.6)years old, (26.5±3.0)kg/m², (129.9±15.9)mm Hg, (78.7±11.2)mm Hg, (2.5±2.4)mmol/L, (3.2±0.9)mmol/L, (5.2±1.0)mmol/L, (5.7±1.6)mmol/L, (38.6±36.1)U/L and (9.1±0.7), all significantly higher than [(40.9±13.8)years old, (22.3±2.7)kg/m², (119.0±15.9)mm Hg, (70.7±10.4)mm Hg, (1.3±1.0)mmol/L, (3.0±0.8)mmol/L, (4.9±0.9)mmol/L, (5.2±0.9)mmol/L, (21.0±19.4)U/L and (8.4±0.5), respectively, P＜0.001], while serum high density cholesterol(HDL-C) levels was (1.1±0.2)mmol/L, significantly lower than [(1.3±1.0)mmol/L, P＜0.001] in individuals without NAFLD; in patients with NAFLD, the systolic blood pressure,diastolic blood pressure,TG,ALT and TyG index in obese group were (133.3±15.3)mm Hg,(82.0±11.3)mm Hg,(2.7±2.5)mmol/L,(46.2±31.5)U/L and (9.2±0.7),all significantly higher than [(129.5±15.7)mm Hg, (78.2±10.9)mm Hg, (2.5±2.4)mmol/L, (37.7±41.0)U/L and (9.1±0.6), P＜0.05] in overweight group and [(125.9±16.4)mm Hg, (74.9±10.7)mm Hg, (2.2±2.3)mmol/L, (30.0±22.2)U/L and (9.0±0.6), P＜0.05] in normal body weight group; the age and serum HDL-C level in the obese group were (42.9±12.8)years old and (1.0±0.2)mmol/L,significantly lower than [(46.6±13.6)years old and (1.1±0.2)mmol/L,P＜0.05] in the overweight group and [(48.3±13.9)years old and (1.2±0.3)mmol/L,P＜0.05] in the normal body weight group; the systolic blood pressure,diastolic blood pressure,blood TG,ALT and TyG index in the overweight group were significantly higher than in the normal body weight group(P＜0.05),and the age and blood HDL-C level in the overweight group were significantly lower than in the normal body weitht group(P＜0.05); the FPG in the obese group was (5.8±1.6)mmol/L,significantly higher than [(5.7±1.5)mmol/L, P＜0.05] in the overweight group; the multivariate Logistic regression analysis showed that the older age, increased BMI, diastolic blood pressure, serum TG, FPG, TyG index, ALT and reduced HDL-C levels were the independent risk factors for NAFLD(P＜0.05), the OR= 1.023, 1.521, 1.014, 0.873, 0.972, 3.992, 1.019 and 0.404, respectively,with the TyG index having the highest OR value; the area under the ROC curve(AUC) by the TyG index for predicting NAFLD was 0.814[95%CI(0.810-0.817), P＜0.001], with an optimal cut-off value of 8.67, the sensitivity of 76.1%, and the specificity of 71.4%, respectively; the AUC by the TyG index combined with BMI and ALT in predicting NAFLD was 0.899[95%CI(0.896-0.901), P＜0.001]. Conclusion The TyG index is an independent risk factor for NAFLD,which has good predictive efficacy for NAFLD,and the predictive performance is enhanced when it combine with BMI and ALT levels. The TyG index might helpful for early diagnosis of NAFLD in outpatient and grassroots hospitals as it is economical,practical,and easy to calculate.

Key words: Non-alcoholic fatty liver disease, Triglyceride glucose index, Logistic analysis, Area under receiver operating characteristic curve, Efficacy