Baseline and changes in cardiometabolic index and incident cardiovascular disease in two prospective cohorts

Background: The relationship between cardiometabolic index (CMI) and cardiovascular disease (CVD) remains unknown in the general population. Existing research has primarily concentrated on baseline CMI, not taking into consideration the changes in CMI over time. Objective: This study aimed to investigate the associations of baseline and changes in CMI with the risk of incident CVD. Methods: This study used data from two prospective cohorts: the China Health and Retirement Longitudinal Study (CHARLS) and the English Longitudinal Study of Ageing (ELSA). Changes in CMI were determined by total CMI, calculated by CMI at baseline plus CMI at the second survey. Results: A total of 8059 participants from CHARLS and 4279 from ELSA were included in baseline CMI analyses. Participants with upper tertile of baseline CMI had increased risks of incident CVD than those with lower tertile (CHARLS, HR 1.36, 95 % CI 1.21-1.53; ELSA, HR 1.24, 95 % CI 1.07-1.43). A total of 4946 participants from CHARLS and 2371 from ELSA were included in CMI change analyses. For the changes in CMI analyses, participants with tertile 3 showed an elevated risk of incident CVD than tertile 1 (CHARLS: HR 1.53, 95 % CI 1.29-1.81; ELSA: HR 1.41, 95 % CI 1.15-1.73). The restricted cubic spine models showed a nonlinear relationship between baseline and total CMI and incident CVD risks in the CHARLS, while a linear relationship in the ELSA. Conclusions: Both baseline and total CMI were associated with an increased risk of CVD. Long-term monitoring of CMI levels is of great importance for CVD prevention in clinical practice.