Association between combined atherogenic and frailty index and cardiovascular events: evidence from the CHARLS cohort

OBJECTIVE: The atherogenic index of plasma (AIP) is a marker of atherosclerosis, while frailty reflects cumulative physiological decline. However, the combined impact of AIP-frailty index (AIP-FI) has not been adequately explored. This study aimed to investigate the association between AIP-FI and the risk of cardiovascular disease (CVD), stroke, and heart disease. METHODS: This prospective cohort study included 6896 participants aged ≥ 45 years from the China Health and Retirement Longitudinal Study (CHARLS) without CVD, stroke, or heart disease at baseline. The Cox proportional hazard models and restricted cubic spline (RCS) analysis were applied to explore the association between AIP-FI with the risk of CVD, stroke, and heart disease. RESULTS: During a median follow-up period of 9 years, 1648 (23.9%) of CVD events, 548 (7.9%) of stroke events, and 1280 (18.6%) of heart disease events were recorded. Cox regression analysis revealed that each 1-unit increment in the AIP-FI was significantly associated with higher risk of CVD (HR: 2.95, 95% CI 2.15, 4.05), stroke (HR: 3.14, 95% CI 1.88, 5.26), and heart disease (HR: 2.72, 95% CI 1.06, 1.89, 3.92). The RCS revealed a significant positive nonlinear relationship between AIP-FI with the risk of CVD, stroke, and heart disease (all P-overall < 0.05, and all P for non-linear < 0.05). CONCLUSIONS: Our study demonstrated that higher AIP-FI was significantly associated with increased risk of CVD, stroke, and heart disease. By integrating metabolic and frailty information, AIP-FI offers an effective and accessible tool for cardiovascular risk assessment, supporting earlier prevention and intervention strategies in the middle-aged and elderly Chinese populations.