Association between the cardiometabolic index and all-cause and cardiovascular mortality in diabetes and prediabetes.

Background: The association between the cardiometabolic index (CMI) and mortality in individuals with diabetes or prediabetes remains unclear. This study sought to explore the association between the baseline CMI and all-cause mortality and cardiovascular disease (CVD) mortality in United States (U.S.) adults with diabetes or prediabetes.

Methods: This cohort study examined the data of 17,992 individuals, aged 18 years and older, with diabetes and prediabetes, who had participated in the National Health and Nutrition Examination Survey (NHANES; 2003-2018). Kaplan-Meier curve, Cox proportional hazards model, and restricted cubic spline (RCS) curve analyses were conducted to explore the relationship between the CMI and all-cause mortality and CVD mortality. Subgroup and sensitivity analyses were conducted to check the robustness of the main findings.

Results: During 137,687 person-years of follow-up (median: 7.4 years), a total of 2,718 all-cause deaths and 891 CVD-related deaths were recorded. In the multivariate adjusted models, the CMI was positively associated with the risk of all-cause mortality and CVD mortality. Specifically, the hazard ratio (HR) estimates for all-cause death and 95% confidence intervals (CIs) for the low to high CMI quartiles were 1.00 (reference), 1.056 (0.875-1.274), 1.156 (0.912-1.464), and 1.42 (1.080-1.867), respectively. While the CVD mortality HRs were 1.00 (reference), 1.041 (0.768-1.41), 1.077 (0.771-1.503), and 1.29 (0.836-1.99), respectively. The RCS analysis showed that the baseline CMI was approximately U-shaped in relation to all-cause mortality (P<0.001) and CVD mortality (P=0.03) in the participants with diabetes and prediabetes. The subgroup analysis revealed a clear interaction between the CMI and all-cause mortality based on age and sex (P=0.01 and P=0.003, respectively). It also revealed a significant interaction between the CMI and CVD mortality based on smoking status and diabetes status (P=0.02 and P=0.01, respectively).

Conclusions: The CMI demonstrated predictive value for the risk of all-cause mortality and CVD mortality among U.S. participants with prediabetes and diabetes. The relationship between the CMI and long-term mortality exhibited an approximately U-shaped pattern, highlighting its potential as a robust indicator for mortality risk stratification in this population.