Metabolic syndrome (MetS) defined by a set of cardio-metabolic features is associated with an increased risk for atherosclerotic cardiovascular disease (ASCVD) and type 2 diabetes mellitus (T2DM).1, 2, 3 Its individual components include an elevated waist circumference [WC], increased triglycerides [TG], low levels of high density lipoprotein cholesterol [HDL-C], elevated fasting glucose and high blood pressure.1, 2, 3 It is a major global problem with no optimum treatment.

Insulin resistance, a central feature of MetS has been advanced as a dominant pathophysiological mechanism for this disorder.3,13.14 Furthermore insulin resistance predisposes to both T2DM and ASCVD.3,4 Chronic low-grade inflammation appears to also be an important pathogenic mechanism in MetS.15 Although the hyperinsulinemic-euglycemic clamp (HIEC) is the gold standard for quantifying insulin resistance, it is expensive, laborious, and not routinely available. Therefore, the use of other measures to detect insulin resistance, such as the homeostasis model assessment insulin resistance (HOMA-IR) and triglyceride-glucose index (TyG), have been studied and validated against the HIEC as reliable surrogates of insulin resistance.

To date HOMA-IR has been the most common surrogate measure of insulin resistance and is used frequently as a research tool in epidemiological and clinical studies5,6 It requires both fasting plasma glucose and insulin levels to compute, the latter can be costly and inconvenient. The concept behind HOMA-IR is that compensatory hyperinsulinemia helps maintain normoglycemia in MetS and prediabetes.4, 5, 6

More recently the TyG index has also been shown to be a reliable measure of insulin resistance. It has been validated against the HIEC technique.7, 8, 9 The majority of studies, however, validating the TyG index emanate from Asian and Latin American populations.8, 9, 10, 11 Surprisingly, the TyG index has not been embraced by investigators in the US.

Recently a large study, the prospective urban, rural epidemiology (PURE) study from 5 continents including 22 countries (n = 141,243 persons), showed that the TyG index predicted cardiovascular disease, cardiovascular mortality and diabetes in both low income(LIC) and medium income (MIC) countries.12 In high income countries (HIC), however, TyG only predicted incident diabetes and not cardiovascular disease or mortality.12

Since MetS is a cardio-metabolic disorder that confers an increased risk for both T2DM(5 fold) and ASCVD(2 fold), the aim of the present study was to determine the value of the TyG index in prediction of insulin resistance, manifested by prediction of MetS. in the present report, we compared the TyG index to HOMA-IR, in an general US population.For this study we used the National Health and Nutrition Examination survey (NHANES) data set, due to a paucity of data from the US. Overall, our findings show that TyG index outperformed HOMA-IR in predicting MetS, and thus it may be a valuable biomarker even in HIC countries for investigating the association of MetS with both T2DM and ASCVD.