Comparison of the triglyceride-glucose index and triglyceride-HDL ratio as discriminators of metabolic syndrome in the elderly population

Abstract Introduction Insulin resistance (IR), defined as decreased cellular sensitivity to insulin, is a common condition in the elderly population and is a central feature of metabolic syndrome (MS). The evaluation of IR requires sophisticated methodology difficult to apply. Therefore, different estimators of this condition have been suggested, such as the triglyceride-glucose index (TyG) and triglyceride-HDL ratio (T/HDL). Studies have shown that the TyG index and T/HDL ratio are good discriminators of the presence of MS and are related to the development and prognosis of cardiovascular disease; however, data in the elderly population are scarce. Purpose To evaluate the TyG index and the T/HDL ratio as markers of metabolic syndrome (MS) in patients over 60 years old who participated in the 2015 SABE Colombian survey. Methods An observational, cross-sectional study was conducted, including 4,076 individuals over 60 years old who participated in the SABE Colombian survey (n=2,450 women and n=1,626 men). The diagnosis of metabolic syndrome (MS) was based on the criteria of the National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III). The discriminatory ability of the TyG index, calculated as Ln(TG mg/dL × glucose mg/dL / 2), and the T/HDL ratio were evaluated for MS. Cut-off points with the highest discriminative capacity were determined separately for men and women. For these cut-off points, sensitivity, specificity, and post-test probabilities were calculated, considering a pre-test probability of 30% for MS, as described in previous studies in our population. Results The cut-off points for MS in the total population were 8.8 for the TyG index (sensitivity = 75.57%, specificity = 81.42%) and 3.25 for the T/HDL ratio (sensitivity = 74.49%, specificity = 75.59%). When stratified by sex, the TyG index maintained nearly the same cut-off point, whereas the T/HDL ratio cut-off was 3.2 for men and 3.0 for women. The correlation between the TyG index and the T/HDL ratio was strong, with a Spearman’s rho of 0.896. The positive post-test probability for each parameter individually was 70.64% vs. 56.54%, while the probability increased to 88.97% when both tests were positive. Conversely, when both tests were negative, the post-test probability was 3.63%. Conclusions The TyG index and T/HDL ratio are effective discriminators of MS in the Colombian population over 60 years old. Given the simplicity of their calculation, they emerge as valuable tools for cardiovascular risk assessment and as alternative markers of insulin resistance (IR) in the elderly population. Unlike insulin determination, triglyceride determination is economic and standardized in laboratories, which offers an advantage over indices that use insulin measurement to evaluate IR. Its simplicity justifies further research on its role as an alternative estimator of IR, with the aim of improving the detection of individuals at higher cardiometabolic risk.ROC curve for triglyceride-glucose index ROC curve for triglyceride-HDL ratio