THE ROLE OF TYG INDEX AS PREDICTOR OF CARDIOVASCULAR EVENTS AMONG YOUNG TO-MIDDLE-AGE STAGE I HYPERTENSIVES

Abstract

Objective: The triglyceride-glucose index (TYG), a surrogate marker of insulin resistance, was shown to be associated with an increased risk of cardiovascular events among people with diabetes or the metabolic syndrome, while its prognostic capacity among young hypertensives is less explored. The aim of the present study was to investigate the role of TYG as predictor of cardiovascular outcomes among young stage I hypertensives, untreated at baseline. Design and method: We investigated 1210 subjects from the HARVEST study, mean age 33.1±8.5 years, 72.8% males. TYG was calculated according to the usual formula. BP was measured with 24-hour ambulatory monitoring. For the analyses, patients were divided into TYG quartiles: 7.008-8.061, 8.063-8.423, 8.424-8.690, 8.691-10.678, respectively. The risk of major adverse cardiovascular events (MACE) was explored by means of survival Cox analyses adjusting for several confounders and risk factors, including lifestyle factors, 24-hour BP and cholesterol. Results: TYG was correlated with BMI (r=0.348, p<0.001), age (0.237, p<0.001), serum uric acid (r=0.349, p<0.001), total cholesterol (r=0.422, p<0.001) and HDL-cholesterol (-0.393, p<0.001), and diastolic BP (0.132, p<0.001). Subjects in the top TYG quartile had the highest percentage of smokers (p<0.001), coffee users (p=0.038) and alcohol drinkers (p=0.010). TYG was significantly correlated with left ventricle mass index (r=0.08, p=0.021), left ventricular septum thickness (r=0.15, p<0.001), and posterior wall thickness (r=0.17, p<0.001). During 17.4 years of follow-up, 108 MACE were accrued. In multivariate Cox analysis the risk of MACE was higher in the two highest TYG quartiles than in the bottom quartile. For the top quartile the hazard ratio was 2.46 (95%CI, 1.17-5.20, p=0.018). The association remained significant also when the lifestyle factors were included in the regression with a hazard ratio of 2.43 (95%CI, 1.14-5.17, p=0.022). This was driven mainly by the strong association found in men with a hazard ratio of 4.84 (95%CI, 1.63-14.39, p=0.004). Conclusions: TYG index is a surrogate marker of insulin resistance, easy to calculate, which significantly correlates with several other metabolic parameters and with left ventricular wall thickness and mass. It is a predictor of adverse cardiovascular outcomes especially in male individuals.