Triglyceride–Glucose Index Predicts Cardiovascular Outcome in Metabolically Unhealthy Obese Population: A Nationwide Population-Based Cohort Study

Background: This study assesses the prognostic value of the triglyceride-glucose (TyG) index for cardiovascular (CV) risk in subgroups based on metabolic health and obesity status. Methods: Originally, 514,866 participants were enrolled from the Korean National Health Insurance Service-National Health Screening Cohort. The study participants were categorized into four groups: metabolically healthy non-obese (MHNO), metabolically unhealthy non-obese (MUNO), metabolically healthy obese (MHO), and metabolically unhealthy obese (MUO). The TyG index was calculated using the following formula: ln (fasting triglyceride [mg/dL]×fasting plasma glucose [mg/dL]/2). Participants were followed from 2009 to 2015 for CV events and CV mortality according to the TyG index. Results: After exclusions, the final study cohort contained 292,206 people. During the follow-up, 9,138 CV events and 1,163 CV deaths were documented. When the high and low TyG groups were compared, the high TyG group had a substantially increased risk of CV events among the MUNO and MUO participants (multivariable-adjusted hazard ratio [HR], 1.18; 95% confidence interval [CI], 1.07-1.30 and 1.27 [1.14-1.42], respectively). In participants with MUO status, CV mortality was also significantly increased in the high TyG group compared with the corresponding low TyG group (multivariable-adjusted HR, 1.48; 95% CI, 1.13-1.93). In contrast, a high TyG index was not related to CV mortality in the MHNO, MHO, and MUNO groups. Conclusion: The predictive value of the TyG index can vary across populations. Among MUO participants, the TyG index was significantly and positively correlated with unfavorable CV outcomes.