Associations of the Triglyceride–Glucose Index and Atherogenic Index of Plasma with the Risk of Acute Coronary Syndrome and the Severity of Coronary Artery Lesions in Patients with Type 2 Diabetes Mellitus

Objective: To investigate the associations of the triglyceride–glucose (TyG) index and the atherogenic index of plasma (AIP) with the risk of acute coronary syndrome (ACS) and the severity of coronary artery lesions in patients with type 2 diabetes mellitus (T2DM). Methods: A total of 377 patients were enrolled in this study and divided into two groups: the T2DM-only group (n = 189) and the T2DM with ACS group (n = 188). Least absolute shrinkage and selection operator (LASSO) regression and multivariate logistic regression were performed to identify independent risk factors for ACS, and a nomogram model was subsequently constructed. Model performance was evaluated in terms of discrimination and calibration using receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA), followed by bootstrap internal validation. The Gensini score was used to assess the severity of coronary artery lesions, and the associations of the TyG index and AIP with lesion severity were further analyzed. Furthermore, subgroup analyses were conducted to evaluate the consistency of these associations. Results: Multivariate logistic regression identified age, SBP, APTT, HbA1c, CREA, the TyG index, and AIP as independent risk factors for ACS in patients with T2DM (all P < 0.05). The constructed nomogram model showed good discrimination (area under curve [AUC] = 0.926), calibration (intercept = 0, slope = 1, Brier score = 0.109), and clinical net benefit. The TyG index and AIP increased significantly with increasing Gensini score in patients with ACS (P < 0.01). Both the TyG index (OR = 14.57) and AIP (OR = 16.82) were positively associated with the severity of coronary lesions, and these associations remained consistent across subgroups defined by sex, age, BMI, and HbA1c (all P for interaction > 0.05). Conclusions: The TyG index and AIP were identified as independent risk factors for ACS in patients with T2DM and were positively associated with the severity of coronary artery lesions. The nomogram model based on these two indices demonstrated favorable discrimination, calibration, and clinical applicability, and may be useful for risk stratification and early identification of ACS in patients with T2DM. However, these exploratory findings require external validation before consideration for clinical application.