Association of Insulin Resistance Surrogates with NAFLD Progression and Disease Severity

Abstract

Background: Non-alcoholic fatty liver disease (NAFLD) is increasingly recognized as the hepatic expression of metabolic dysfunction, closely linked to insulin resistance (IR). Surrogate markers such as the triglyceride-glucose (TyG) index, TyG-BMI, and TyG-WC have emerged as practical, low-cost tools for assessing IR and NAFLD risk. However, data from South Asian populations characterized by high metabolic risk is limited. Objective: To evaluate the association of TyG-index and TyG-based anthropometric indices with NAFLD presence and severity, and to determine their predictive accuracy for NAFLD among overweight and obese adults in Bangladesh. Methods: This cross-sectional study was conducted at the Department of Biochemistry and Molecular Biology, BSMMU, Dhaka, from March 2023 to February 2024. A total of 253 adults (aged 18–75 years) with overweight or obesity were selected using purposive sampling. Clinical, anthropometric, and biochemical assessments were performed. Abdominal ultrasonography determined NAFLD diagnosis and grading. TyG-index, TyG-BMI, and TyG-WC were compared between groups and across NAFLD grades. ROC curves assessed predictive performance. Results: NAFLD prevalence was 51% (n=129). Among NAFLD subjects, Grade-I predominated (69%), followed by Grade-II (22%) and Grade-III (9%). NAFLD subjects had significantly higher TG, FPG, and ALT levels (p<0.001). TG, FPG, and ALT increased progressively with NAFLD grade. TyG-index, TyG-BMI, and TyG-WC were significantly higher in NAFLD subjects than controls (p<0.001). Across NAFLD grades, TyG-index and TyG-WC showed significant upward trends, highest in Grade-III. TyG-BMI did not differ significantly across grades. AUCs for prediction of NAFLD were: TyG (0.708), TyG-BMI (0.803), and TyG-WC (0.829). TyG-WC demonstrated the strongest predictive performance with optimal sensitivity and specificity. Conclusion: TyG-based indices, especially TyG-WC, are robust predictors of NAFLD among overweight and obese adults. TyG-index and TyG-WC also reflect disease severity. These low-cost markers offer practical advantages for early identification and risk stratification in resource-limited settings. Incorporating TyG-based indicators into routine metabolic evaluation may improve NAFLD detection and prevention strategies in South Asia.