C-reactive protein-triglyceride glucose index in evaluating cardiovascular disease and all-cause mortality incidence among individuals across stages 0–3 of cardiovascular–kidney–metabolic syndrome: a nationwide prospective cohort study

Objective The American Heart Association (AHA) developed the notion of cardiovascular-kidney-metabolic (CKM) syndrome, which emphasizes the interconnection of heart, kidney, and metabolic illnesses. The C-reactive protein-triglyceride-glucose (CTI) represents a potential indicator to assess the resistance to insulin and an inflammatory response. However, the connection among CTI, cardiovascular disease (CVD) incidence, and overall mortality rates remains uncertain, particularly among individuals at CKM stages 0-3. Methods The China Health and Retirement Longitudinal Study (CHARLS) enrolled 17,705 middle-aged and elderly people. The primary outcome was the occurrence of CVD and overall mortality rates. The CTI was obtained by 0.412* Ln (CRP [mg/L]) + Ln (TG [mg/dl] × FPG [mg/dl])/2. The correlation among CTI and CVD incidence and overall mortality was assessed via Cox proportional hazard models, Kaplan-Meier curves and restricted cubic spline (RCS) analysis. To improve the study results, a stratified analysis evaluated the influence of varying socio-demographic characteristics. Results During a 9-years following-up, 5534 participants (9.2%) experienced a CVD event, while 121 participants (2.1%) experienced all-cause mortality. RCS analysis revealed a notable non-linear association between CTI and CVD occurrence, as well as a linear association between CTI and all-cause death. After comprehensive multivariate adjustment, the data showed a striking 97% increase in overall mortality risk for every 1-unit rise in continuous CTI measurements. Conclusions Findings show that higher CTI levels independently forecast CVD and death, highlighting its potential as a biomarker for individuals with CKM stages 0-3.