The Triglyceride–Glucose (TyG) Index and Cardiovascular Diseases: A Narrative Review

Background: The triglyceride–glucose (TyG) index, calculated from fasting triglyceride and glucose levels, has emerged as a simple and cost-effective surrogate marker of insulin resistance (IR). Given that IR is a pivotal mechanism underlying cardiovascular disease (CVD), the TyG index has gained increasing attention in recent years. Objective: This review summarizes the current evidence on the association between the TyG index and cardiovascular risk, exploring its biochemical basis, role in metabolism, epidemiological findings, and clinical implications. Methods: A narrative review of published studies was conducted, focusing on the predictive value of the TyG index for insulin resistance, diabetes, metabolic syndrome, and CVD outcomes. Findings from cohort, cross-sectional, and meta-analysis studies were integrated to provide a comprehensive overview. Results: Multiple epidemiological and clinical studies demonstrate that higher TyG index values are associated with an increased risk of cardiovascular events, independent of traditional risk factors. Compared to the homeostasis model assessment of insulin resistance (HOMA-IR), the TyG index shows greater accessibility and predictive capacity. However, heterogeneity in cut-off thresholds and limited prospective and interventional trial data remain major challenges. Conclusions: The TyG index represents a promising biomarker for cardiovascular risk assessment and may serve as a supplementary tool for early screening, particularly in young and asymptomatic adults. Future large-scale prospective and interventional studies are warranted to standardize cut-off values and establish its role in clinical practice.