Comparison of triglyceride glucose index and modified triglyceride glucose indices in predicting cardiovascular diseases incidence among populations with cardiovascular-kidney-metabolic syndrome stages 0–3: a nationwide prospective cohort study

Cardiovascular-kidney-metabolic (CKM) syndrome has been recently proposed by American Heart Association recently. The triglyceride glucose (TyG) index and TyG-related indices combined with obesity indicators have proven to be associated with the incidence of cardiovascular diseases (CVD). However, there are few studies to explore whether these associations exist among people with CKM syndrome stages 0–3. A total of 7,364 participants from the China Health and Retirement Longitudinal Study were included. Cox hazard regression and restricted cubic spline regression were used to analyze the associations of these indices with CVD incidence. To compare predictive performance, time-dependent Harrell's C-indices, net reclassification index and integrated discrimination improvement were conducted. The CVD incidence was 20.55% over nine years. The TyG single index and all the modified TyG indices were capable of predicting CVD incidence. RCS regression analyses showed that all indicators had linear relationships with CVD incidence and these linear relationships of TyG combined with waist circumference (TyG-WC) or waist-to-height ratio (TyG-WHtR) still existed in CKM stage 1, stage 2 and stage 3. TyG-WC (C-index: 0.621, p < 0.001) and TyG-WHtR (C-index: 0.621, p < 0.001) almost had the highest C-indices in predicting CVD incidence, compared to single TyG index (C-index: 0.611, p < 0.001) and TyG combined with body mass index (C-index: 0.616, p < 0.001). The TyG index and all the modified TyG indices were independent predictors of CVD incidence among people with CKM syndrome stages 0–3. It was found that modified indices had better predictive performance, especially TyG combined with waist circumference or waist-to-height ratio.