Link between C-reactive protein-triglyceride glucose index and cardiovascular disease risk in diverse glycemic statuses: a nationwide prospective cohort study

The C-reactive protein-triglyceride-glucose index (CTI) is a novel biomarker that integrates measures of insulin resistance and inflammation. Its association with cardiovascular disease (CVD) risk across various glycemic statuses remains unclear. This prospective study included 7,584 middle-aged and elderly participants from the China Health and Retirement Longitudinal Study (CHARLS). CTI was calculated using the formula 0.412*Ln(CRP) + Ln(TG × FPG)/2. Cox proportional hazards models and restricted cubic splines were employed to evaluate the relationship between CTI and CVD risk, with subgroup analyses conducted based on gender, age, and glycemic status. Over a median follow-up period of 108.1 months, 1,989 participants (26.23%) developed CVD. The incidence of CVD increased significantly across ascending CTI quartiles (Q1: 20.78% to Q4: 31.65%). A positive linear association was observed that remained consistent across both genders and age groups. Higher CTI quartiles (Q3/Q4) were associated with a significantly elevated risk of CVD, particularly among males (hazard ratio [HR] up to 1.58) and middle-aged individuals (HR 1.57). Notably, an elevated CTI was linked to an increased risk of CVD in participants with normal glucose regulation but not in those classified as prediabetic or diabetic. The CTI serves as an independent predictor of CVD risk within the general middle-aged and elderly population. This association is most pronounced in individuals exhibiting normal glucose regulation, underscoring the potential utility of CTI for early risk stratification as well as the necessity for tailored prevention strategies informed by glycemic status.