Usefulness of Triglyceride-Glucose Index and Homeostatic Model Assessment for Predicting Coronary Microvascular Dysfunction

Background Coronary microvascular dysfunction (CMD) is a common occurrence in individuals with insulin resistance (IR). Homeostatic model assessment for insulin resistance (HOMA-IR) is a widely used surrogate marker of IR, although recent studies suggest Triglyceride-Glucose (TyG) index is a superior marker of IR that had a better accuracy to predict Type 2 Diabetes or cardiovascular outcomes than HOMA-IR. Objectives We aimed to assess the accuracy and usefulness of TyG index and HOMA-IR for predicting CMD as assessed with echocardiographic coronary flow reserve (CFR) measurement. Methods All cases included in the institutional CFR registry were retrospectively reviewed, and 656 cases without epicardial coronary artery disease and without major risk factors for atherosclerosis were included. A CFR ≤2.0 was defined as CMD. Results TyG index was available in all cases, while HOMA-IR was available in 398 cases. Both TyG index and HOMA-IR were associated with CMD on univariate analyses, while after adjustment for potential confounders HOMA-IR (OR:1.38, 95%CI:1.14-1.67, p=0.001) but not TyG index(OR:1.48, 95%CI:0.82-2.67, p=0.19) was associated with CMD. The predictive accuracy of HOMA-IR (c-statistic:0.63, 95%CI:0.54-0.72, p=0.003) was higher than TyG index(c-statistic:0.55, 95%CI:0.47-0.63, p=0.13), although the difference was not statistically significant (DeLong p=0.23). There was strong evidence favoring a true difference between CMD vs. non-CMD groups for HOMA-IR (BF10:3507) but not for TyG index(BF10:0.66). Conclusions HOMA-IR, but not TyG index, is closely associated with CMD.