Triglyceride Glucose Index and Related Parameters (Triglyceride Glucose-Body Mass Index and Triglyceride Glucose-Waist Circumference) Identify Nonalcoholic Fatty Liver and Liver Fibrosis in Individuals with Overweight/Obesity

Background: The triglyceride glucose (TyG) index has been proposed as a reliable surrogate marker for nonalcoholic fatty liver disease (NAFLD). Furthermore, NAFLD is strongly related with obesity. This study aimed to compare TyG index and its related parameters (TyG-waist circumference [WC] and TyG-body mass index [BMI]), comprising TyG and obesity markers, in predicting NAFLD and liver fibrosis in overweight/obese individuals without diabetes. Methods: This was a cross-sectional study consisting of 184 overweight/obese people (96 with and 88 without NAFLD), 30-65 years of age. TyG, TyG-BMI, and TyG-WC were computed using the established formula. Liver stiffness measurement (LSM) and controlled attenuation parameter (CAP) were determined by transient elastography (FibroScan). Results: In correlation analyses, CAP and LSM were significantly associated with WC, BMI, TyG, TyG-BMI, and TyG-WC. Regression analyses highlighted TyG-WC as a significant predictor of NAFLD, with the highest standardized odds ratio (2.25, P < 0.001); while liver fibrosis was associated more strongly with TyG-BMI. In receiver operating characteristic (ROC) analysis, TyG-WC showed the largest area under the ROC curve (AUC) for detection of NAFLD (0.693, 95% confidence interval [CI]: 0.617-0.769). However, TyG-BMI was a better discriminator of liver fibrosis (AUC: 0.635, 95% CI: 0.554-0.714). TyG-WC value of 876 (sensitivity: 81.3%, specificity: 52.3%) and TyG-BMI value of 259 (sensitivity: 78.3%, specificity: 51.3%) were the optimal cutoff points to predict NAFLD and liver fibrosis, respectively. Conclusions: The results highlight the significant associations of TyG and its related indices with NAFLD, with TyG-WC being a better indicator. TyG-BMI and TyG-WC could reliably predict liver fibrosis in this population. These indices appear to be simple, practical, and affordable tools for screening NAFLD and liver fibrosis in clinical settings.