Cumulative exposure to TyG-BRI and risk of incident cardiovascular disease across CKM syndrome stages 0–3: evidence from the CHARLS Prospective Cohort

Despite advances in cardiovascular risk stratification, tools that adequately capture cumulative cardiometabolic burden remain limited, particularly in non-Western populations. The association between cumulative triglyceride–glucose index and body roundness index (cumTyG-BRI) and cardiovascular disease (CVD) across the spectrum of Cardiovascular–Kidney–Metabolic (CKM) syndrome remains to be elucidated. We conducted a prospective cohort analysis of 3,367 adults aged ≥ 45 years from the China Health and Retirement Longitudinal Study (CHARLS) spanning CKM stages 0–3 (follow-up: 2015–2020). CumTyG-BRI was computed via the trapezoid method. Cox models estimated hazard ratios (HRs) for incident CVD, with restricted cubic splines assessing nonlinearity and Kaplan–Meier curves illustrating cumulative risk. Robustness was confirmed via subgroup analyses and sensitivity analyses. Among 3,367 participants, 638 CVD events occurred (18.9%). Higher CumTyG-BRI was associated with greater CVD risk in a threshold-dependent rather than linear manner (Q4 vs. Q1: HR = 1.55, 95% CI: 1.19–2.02; P for trend < 0.001), with risk elevation concentrated at the highest exposure quartile and corroborated by restricted cubic spline analysis. Kaplan-Meier curves showed progressively diverging survival probabilities (log-rank P < 0.0001). In this prospective cohort of Chinese adults aged ≥ 45 years, cumTyG-BRI showed a threshold-dependent association with incident CVD risk. Given that its constituent measures require only readily available metabolic parameters, cumTyG-BRI warrants further investigation as a potential index for CVD risk stratification, particularly in populations with high cardiometabolic burden.