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 (odds ratio [OR]:1.38, 95% confidence interval [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.