Association between TyG index and long-term prognosis of patients with ST-segment elevated myocardial infarction undergoing percutaneous coronary intervention: a retrospective cohort study

Objective To assess the association between the serum triglyceride-glucose product index (TyG index) and the risk for all-cause mortality in patients with ST-segment elevated myocardial infarction (STEMI). Design Retrospective. Setting and participants This retrospective study included 896 patients with STEMI who underwent percutaneous coronary intervention (PCI) at a comprehensive university-affiliated hospital between January 2016 and January 2019. Methods Patients were equally divided into quartiles (Q1, Q2, Q3 and Q4 group) according to TyG index values. Primary endpoint All-cause mortality. Results After a median follow-up of 3 years, 108 (17.1%) patients died. TyG index was independently associated with increased all-cause mortality (OR, 1.39; 95% CI, 1.22 to 1.58) after adjusting for age, sex, low-density lipoprotein cholesterol (LDL-c), cardiac troponin I, B-type natriuretic peptide, delayed PCI, post-PCI complications, medication and left ventricular ejection fraction. The adjusted OR was 1.31 (95% CI, 0.62 to 2.77) for Q2, 2.12 (95% CI, 1.01 to 4.53) for Q3 and 4.02 (95% CI, 1.90 to 8.78) for Q4 compared with the lowest quartile (Q1) (p for trend<0.001). In the restricted cubic spline regression model, the relationship between the TyG index and the risk of all-cause mortality was linear (p for non-linear=0.575). Each unit increase in the TyG index was associated with a 68% increase in the multivariate risk for all-cause mortality (OR 1.68; 95% CI, 1.20 to 2.38). In the subgroup analysis, there was an interaction between LDL-c and the TyG index on the risk of all-cause mortality (p for interaction=0.007). Conclusion The TyG index was significantly associated with the long-term all-cause mortality among patients with STEMI who underwent PCI.