The triglyceride glucose (TyG) index is associated with decreased myocardial mechano-energetic efficiency in individuals with different glucose tolerance status.

Abstract

Background: This investigation had two main objectives: (1) to compare the triglyceride-glucose (TyG) index with the homeostasis model assessment of insulin resistance (HOMA-IR) in relation to insulin-stimulated myocardial glucose metabolic rate (MrGlu), measured by a dynamic positron emission tomography (PET) scan using 18F-fluorodeoxyglucose (18F-FDG) coupled with a euglycemic-hyperinsulinemic clamp; and (2) to assess whether the TyG index correlates with myocardial mechano-energetic efficiency (MEE).

Methods: We evaluated MrGlu in 46 participants who had no prior diagnosis of coronary heart disease. Myocardial MrGlu was quantified by 18F-FDG PET during a euglycemic-hyperinsulinemic clamp. In a larger cohort of 1820 individuals, myocardial MEE per gram of left ventricular mass (MEEi) was measured echocardiographically. The TyG index was computed as the Ln [fasting triglycerides (mg/dL) × fasting glucose (mg/dL)/2].

Results: When compared to HOMA-IR, the TyG index exhibited a stronger correlation with myocardial MrGlu (Pearson's r = -.566 for TyG vs. -.471 for HOMA-IR). Within the larger cohort, individuals in the highest TyG quartile showed significantly reduced MEEi compared to those in the lowest quartile (p < .001). Stepwise multivariate linear regression confirmed that the TyG index was the most significant determinant of MEEi, independent of traditional cardio-metabolic risk factors.

Conclusions: Our findings suggest that the TyG index is superior to HOMA-IR as an indicator of cardiac insulin resistance and that it independently correlates with MEEi. Thus, the TyG index may serve as a valuable, readily available tool to identify subjects at elevated cardiovascular risk.