Association between the Triglyceride-Glucose Index and Cardiovascular Risk and Mortality across Different Diabetes Durations: A Nationwide Cohort Study

Background: We aimed to assess the association between triglyceride-glucose (TyG) index and cardiovascular disease (CVD) risk and mortality in a large cohort of diabetes patients. Methods: A retrospective cohort study of 1,090,485 participants from the Korean National Health Insurance Service database was conducted. Participants were stratified into TyG quartiles. Results: Higher TyG index quartiles were significantly associated with an increased CVD risk and mortality risk. In fully adjusted models, participants in the highest TyG quartile (Q4) had an 18% higher risk of CVD (hazard ratio [HR], 1.18; 95% confidence interval [CI], 1.13 to 1.23) and a 16% higher risk of mortality (HR, 1.16; 95% CI, 1.11 to 1.23) compared to those in the lowest quartile (Q1). The association was particularly pronounced in patients with fasting glucose ≥126 mg/dL (CVD [HR, 1.33; 95% CI, 1.29 to 1.37], mortality [HR, 1.23; 95% CI, 1.20 to 1.26]; P for interaction <0.001). Patients with a diabetes duration of ≥10 years showed the strongest association between the TyG index and CVD risk (HR, 1.44; 95% CI, 1.38 to 1.50), while the mortality risk was particularly elevated in those with a diabetes duration of less than 5 years (HR, 1.23; 95% CI, 1.18 to 1.30). Subgroup analyses revealed stronger associations between TyG index and CVD risk in younger participants, non-obese individuals, and non-smokers. Conclusion: The TyG index is a significant predictor of CVD and mortality in diabetic patients, particularly in those with poor glycemic control or longer disease duration.