Supplementary Material for: Associations of Cardiovascular-Kidney-Metabolic syndrome with premature mortality and life expectancies in US adults: a cohort study

Background: The American Heart Association has recently updated the Cardiovascular-Kidney-Metabolic (CKM) Health Advisory, proposing a new framework for defining, staging, and predicting CKM risk. However, the prevalence and adverse effects of the CKM stages remain insufficiently characterized.
Methods: We analyzed data from the National Health and Nutrition Examination Survey (NHANES) (1999–2018), including 18,350 US adults aged 20–79 years. CKM syndrome encompasses subclinical or clinical cardiovascular disease (CVD), chronic kidney disease (CKD), and metabolic risk factors. The participants were categorized into four CKM stages based on their clinical severity. We assessed associations of CKM stages with mortality risk and life expectancy.
Results: Only 12.9% of participants were classified as having CKM stage 0. The prevalence of CKM stages 1, 2, 3, and 4 was 23.1%, 53.6%, 3.6%, and 6.7%, respectively. Compared with CKM stage 0, individuals in stage 4 had a markedly higher risk of all-cause mortality (HR: 4.30, 95% CI: 2.95–6.26) and lost 15.5 (12.5–19.8) years of life at age 50. Sex and racial/ethnic disparities were also observed.
Conclusions: A higher CKM stage was strongly associated with increased mortality and reduced life expectancy. Our findings underscore the urgent need for enhanced CKM health management, social support, and policy intervention.