Response: Triglyceride-Glucose Index Predicts Cardiovascular Outcome in Metabolically Unhealthy Obese Population: A Nationwide Population-Based Cohort Study (J Obes Metab Syndr 2022;31:178-86).

J Obes Metab Syndr 2023;32:181-182 The triglyceride glucose (TyG) index is considered a surrogate marker of cardiovascular disease (CVD) and mortality using the parameter of insulin resistance. Numerous studies have investigated the associations between the TyG index and cardiovascular outcomes, including cardiovascular mortality. A recent meta-analysis and systematic review evaluated associations between the TyG index and the risks of CVD and mortality in the general population.1 Twelve cohort studies involving 6,354,990 participants were analyzed. Higher TyG index values were significantly associated with an increased incidence of CVD; however, the TyG index was not correlated with mortality, including cardiovascular mortality in analyses.1 A subgroup analysis of the population without diabetes revealed no significant association between myocardial infarction incidence and the TyG index, indicating the heterogeneous implications of this index across populations.2 The present study contributes to the literature because we focused on the specific population in which the TyG index could be a useful surrogate marker for an elevated CVD risk.3 Our results demonstrated that the TyG index could predict CVD mortality only in participants with metabolically unhealthy obesity (MUO), and that the index is substantially and consistently associated with CVD regardless of the metabolic health phenotype or presence of obesity.3 In a letter to the editor, the author stated that assessing the predictive value of the TyG index for CVD outcomes would provide greater benefit if we considered changes in the TyG index as well as the obese metabolic health phenotype. Several recent studies have reported the significant effect of longitudinal changes in the TyG index on CVD risk. We appreciate the letter author for highlighting these important points. A study involving 62,443 healthy Chinese people found that CVD risk increased with quartile of change in the TyG index during a median follow-up of 7.01 years, and that adding change in the TyG index to a baseline risk model for CVD improved its predictive power.4 Another prospective cohort study involving 36,359 participants with a median observation period of