Triglyceride-glucose index predicts type 2 diabetes mellitus more effectively than oral glucose tolerance test-derived insulin sensitivity and secretion markers

Aims: We explored the role of the triglyceride-glucose (TyG) index as an early and superior predictor of type 2 diabetes mellitus (T2DM) in individuals with normal glucose tolerance (NGT) using a community-based Korean cohort over 18 years. Methods: We retrospectively examined 6,072 adults with NGT from the Korean Genome and Epidemiology Study. Cox proportional hazard regression models were employed to evaluate the risk of incidence of T2DM and receiver operating characteristic analysis was used to calculate the area under the curve (AUC). Results: At baseline, the TyG index correlated with the homeostasis model assessment of insulin resistance (HOMA-IR) and the composite insulin sensitivity index (ISI) (beta: 0.045, p < 0.001; beta: -0.105, p < 0.001, respectively). Over the 18-year follow-up period, 999 individuals developed T2DM. An increase in the TyG quartile independently predicted the incidence of T2DM [hazard ratio, 2.36 (1.9-2.93) for Q4]. The AUC value of the TyG index was 0.642, the highest value among HOMA-IR and OGTT-derived insulin sensitivity and secretion markers. Conclusions: The TyG index is associated with HOMA-IR and composite ISI even with NGT. The TyG index demonstrated independent predictability for T2DM incidence in individuals with NGT, better than OGTT-derived insulin sensitivity and secretion markers.