Triglyceride-glucose index as a suitable non-insulin-based insulin resistance marker to predict cardiovascular events in patients undergoing complex coronary artery intervention: a large-scale cohort study

Background Insulin resistance (IR), a hallmark of proceeding diabetes and cardiovascular (CV) disease, has been shown to predict prognosis in patients undergoing percutaneous coronary intervention (PCI). The triglyceride-glucose (TyG) index, triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio and metabolic score for insulin resistance (METS-IR) have been shown to be simple and reliable non-insulin-based surrogates for IR. However, limited studies have determined the associations between distinct non-insulin-based IR markers and CV outcomes in patients undergoing complex PCI who are at higher risk of CV events after PCI. Therefore, this study aimed to investigate and compare the prognostic value of these markers in patients undergoing complex PCI.Methods This was a descriptive cohort study. From January 2017 to December 2018, a total of 9514 patients undergoing complex PCI at Fuwai Hospital were consecutively enrolled in this study. The 3 IR indices were estimated from the included patients. The primary study endpoint was CV events, defined as a composite of CV death, nonfatal myocardial infarction and nonfatal stroke.Results During a median follow-up of 3.1 years, 324 (3.5%) CV events occurred. Multivariable Cox regression models showed per-unit increase in the TyG index (hazard ratio [HR], 1.42; 95% confidence interval [CI] 1.13-1.77), rather than per-unit elevation in either Ln(TG/HDL-C ratio) (HR, 1.18; 95%CI 0.96-1.45) or METS-IR (HR, 1.00; 95%CI 0.98-1.02), was associated with increased risk of CV events. Meanwhile, adding the TyG index to the original model led to a significant improvement in C-statistics (0.618 vs. 0.627, P < 0.001), NRI (0.12, P = 0.031) and IDI (0.14%, P = 0.003), whereas no significant improvements were observed when adding Ln (TG/HDL-C ratio) or METS-IR (both P > 0.05) to the original model.Conclusions The TyG index, not TG/HDL-C ratio and METS-IR, was positively associated with worse CV outcomes in patients undergoing complex PCI. Our study, for the first time, demonstrated that the TyG index can serve as the suitable non-insulin-based IR marker to help in risk stratification and prognosis in this population.