Discriminating Prognostic Impacts of Insulin Resistance and HbA1c on chronic outcomes of stable coronary artery disease

Background: The major adverse cardiovascular events (MACE) in stable coronary artery disease (SCAD) can be mechanistically categorized into acute and chronic events. Accurate risk stratification of these distinct outcomes is crucial for personalized management of SCAD patients. Insulin resistance (IR) and hyperglycemia may differentially predict these outcomes, but their comparative prognostic value remains unclear. Methods: This retrospective cohort study analyzed 944 SCAD patients post-percutaneous coronary intervention (PCI), followed for 32.18 months. Receiver operating characteristic (ROC) curves evaluated the predictive capacity of the triglyceride-glucose (TyG) index (IR marker) and glycated hemoglobin (HbA1c) for MACE subtypes. Patients were stratified by TyG (optimal cutoff) and HbA1c (clinical thresholds) to assess risk stratification in diabetic and non-diabetic subgroups. Results: The TyG index independently predicted overall MACE and repeat revascularization (HR: 1.574, P= 0.021; HR: 1.379, P= 0.027), while HbA1c predicted MACE, heart failure, and stent thrombosis (P< 0.05). Neither marker predicted acute events (acute myocardial infarction or stroke). Combined TyG-HbA1c improved prediction, with AUC for cardiac death rising to 0.901 (P= 0.016). Non-diabetic patients with high TyG-high HbA1c had the highest MACE risk (HR: 2.196, P= 0.009), whereas diabetic patients with high TyG-low HbA1c were at greatest risk (HR: 3.375, P= 0.038). Conclusions: The TyG index better forecasts chronic vascular complications, while HbA1c more strongly predicts chronic myocardial injury. Neither predicts acute MACE. These findings highlight distinct roles of IR and glycemic control in SCAD prognosis, guiding tailored prevention strategies.