Association Between the Triglyceride-Glucose Index and Clinical Outcomes Modified by Diabetes Duration in Patients with Acute Coronary Syndrome and Type 2 Diabetes Mellitus

Background: An elevated triglyceride-glucose (TyG) index is strongly linked to an increased risk of cardiovascular events in patients with acute coronary syndrome (ACS) and type 2 diabetes mellitus (T2DM). However, the potential impact of increasing diabetes duration on the association between the TyG index and cardiovascular risk remains unclear. Methods: Consecutive patients admitted for ACS with T2DM received PCI between March 2016 and March 2020 were enrolled in the analysis. A total of 7093 patients were categorized into tertiles according to the TyG index and T2DM duration. The primary outcome was ischemic events, composed of cardiac death, myocardial infarction, and/or stroke at 5 years. The main secondary outcomes were 5-year cardiac death and all-cause death. Interaction terms and non-linear associations of the TyG index with the clinical outcomes were examined across diabetes durations. Results: Over 5 years, 753 (10.6%) experienced ischemic events, 375 (5.3%) cardiac death, and 636 (9.0%) all-cause death. Higher TyG index and longer diabetes duration independently associated with all outcomes. Compared with the lowest TyG tertile, the highest tertile had adjusted hazard ratios (HRs) of 1.55 (95% CI: 1.29– 1.88) for ischemic events and 1.23 (1.10– 1.38) for all-cause death. The association between TyG index and ischemic events was strongest in the shortest duration group (HR: 1.43), with significant interaction for ischemic and cardiac death (both p < 0.05). Conclusions: A higher TyG index was independently associated with an increased risk of ischemic events and mortality among patients with ACS and T2DM. This association appeared to be attenuated with longer diabetes duration, suggesting that the prognostic relevance of the TyG index may vary according to the chronicity of diabetes.