Abstract

Background: Insulin resistance (IR) plays an important role in metabolic dysregulation and adverse outcomes in acute coronary syndrome (ACS). However, assessment of IR during the acute phase of ACS is challenging, as stress-induced hyperglycemia may confound glucose-based surrogate indices. Objective: This study aimed to evaluate the correlation and diagnostic performance of multiple surrogate indices of IR in comparison with HOMA2-IR in non-diabetic patients with ACS during the acute phase of hospitalization. Methods: A cross-sectional study was conducted in 116 non-diabetic patients with ACS and 120 healthy control individuals. The healthy control group was used to establish a population-specific cut-off for HOMA2-IR (≥ 1.35). Surrogate indices of IR were calculated from fasting biochemical measurements obtained within 24–48 hours of admission. Diagnostic performance was assessed using the area under the receiver operating characteristic curve (AUC), Spearman’s correlation analysis, multivariable logistic regression, and reclassification metrics, including net reclassification improvement (NRI) and integrated discrimination improvement (IDI). Results: The McAuley index demonstrated the highest discriminative ability for IR (AUC = 0.863; 95% CI: 0.794–0.923) and the strongest inverse correlation with HOMA2-IR (ρ = –0.798; p < 0.001). In multivariable analyses adjusted for confounders, the McAuley index remained a strong independent predictor of IR (adjusted OR = 0.302; 95% CI: 0.188–0.485; p < 0.001). TyG-BMI showed an independent association only when BMI was excluded from the covariates, whereas TyG, METS-IR, and lipid ratios showed limited or no diagnostic utility. Reclassification analyses confirmed the superior performance of the McAuley index over non-insulin-based indices (the total NRI ranged from 1.042 to 1.230). Conclusions: Among non-diabetic patients with acute coronary syndrome during the acute phase, surrogate indices of IR showed variable performance. Glucose-based indices demonstrated limited diagnostic accuracy, whereas the insulin-based McAuley index showed the strongest concordance with HOMA2-IR and the most consistent diagnostic performance among the indices evaluated.

Key words: Insulin resistance; acute coronary syndrome; McAuley index; TyG-BMI; HOMA2-IR.