Modified cardiometabolic index predicts mortality in adults with cardiovascular-kidney-metabolic syndrome better than traditional indices.

This prospective cohort study analyzed data from the National Health and Nutrition Examination Survey (NHANES) spanning 1999 to 2018. The population consisted of 5,189 adults with cardiovascular-kidney-metabolic syndrome (CKM) across stages 0 to 4. Researchers compared the modified cardiometabolic index (MCMI) against traditional indices, specifically the cardiometabolic index (CMI) and triglyceride-glucose index (TyG). The primary outcomes included associations with CKM staging, all-cause mortality, and cardiovascular mortality, with secondary outcomes evaluating predictive performance.

During the median 10.4-year follow-up, the MCMI showed a nonlinear association with CKM staging, described as a decelerating increase with an adjusted odds ratio of 3.90 (95% CI: 3.38-4.50). For all-cause mortality, an MCMI greater than 3.5 exhibited a threshold effect; compared to the first quartile, the fourth quartile had a hazard ratio of 1.412 (95% CI: 1.046-1.907). After extensive adjustments, the MCMI remained independently associated with all-cause mortality, with a hazard ratio of 1.22 (95% CI: 1.05-1.40).

Regarding cardiovascular mortality, the MCMI displayed a fluctuating nonlinear pattern, identifying low-risk intervals between 3.0 and 3.5, and high-risk intervals below 2.5 or above 4.0. When accounting for competing risks, the study noted a substantial underestimation of true effects, with a subdistribution hazard ratio of 3.25 (trend P<0.001) for the highest versus lowest quartile. In terms of predictive performance, the MCMI demonstrated superior capability over CMI and TyG, with a mean area under the curve difference of 0.0243.

No adverse events, serious adverse events, discontinuations, or tolerability data were reported, as the MCMI is a calculated index rather than a therapeutic intervention. Key limitations include the observational nature of the study, which precludes causal conclusions about the index itself, and the reliance on NHANES data. Mediation analysis indicated that diabetes mediated 45.5% of the MCMI-cardiovascular mortality risk. While the MCMI may serve as a clinical cut-off for risk stratification, these findings require validation in diverse clinical settings before altering practice.