Prognostic Value of Triglyceride and Glucose Index for Incident Type 2 Diabetes beyond Metabolic Health and Obesity

BACKGROUND: Metabolically healthy obese (MHO) phenotype is metabolically heterogeneous in terms of type 2 diabetes (T2D). Previously, the triglyceride and glucose (TyG) index has been considered for identifying metabolic health and future risk of T2D. This study aimed to evaluate the risk of incident T2D according to obesity status and metabolic health, categorized by four different criteria and the TyG index. METHODS: The study included 39,418 Koreans without T2D at baseline. The risk of T2D was evaluated based on four different definitions of metabolic health and obesity status and according to the baseline TyG index within each metabolic health and obesity group. RESULTS: During the median follow-up at 38.1 months, 726 individuals developed T2D. Compared with the metabolically healthy non-obese (MHNO) group with low TyG index, the MHO group with high TyG index showed increased risk of T2D in all four definitions of metabolic health with multivariate-adjusted hazard ratios of 2.57 (95% confidence interval [CI], 1.76 to 3.75), 3.72 (95% CI, 2.15 to 6.43), 4.13 (95% CI, 2.67 to 6.38), and 3.05 (95% CI, 2.24 to 4.15), when defined by Adult Treatment Panel III, Wildman, Karelis, and homeostasis model assessment (HOMA) criteria, respectively. CONCLUSION: MHO subjects with high TyG index were at an increased risk of developing T2D compared with MHNO subjects, regardless of the definition of metabolic health. TyG index may serve as an additional factor for predicting the individual risk of incident T2D in MHO subjects.