Cardiovascular-kidney-metabolic syndrome in korean: a nationwide stage-specific epidemiology and risk of major adverse cardiovascular events

Background Cardiovascular–kidney–metabolic (CKM) syndrome, which encompasses metabolic, renal, and cardiovascular disorders, is a major global health challenge. Despite its clinical significance, evidence regarding the prevalence, clinical characteristics, and associated risk of major adverse cardiovascular events (MACE) and all-cause mortality across distinct CKM syndrome stages remains limited. This study firstly evaluated the prevalence and clinical characteristics of CKM syndrome stages and their relationship with MACE in a nationally representative Korean cohort. Methods We conducted a retrospective cohort study using data from the 2009–2010 National Health Screening Program administered by the Korea National Health Insurance Service. Participants were classified into CKM syndrome stages. MACE was defined as nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death, with outcomes analyzed via Kaplan–Meier curves and Cox proportional hazards regression over an average follow-up of 11.6 years. Results Among a total of 4,360,374 Korean adults, the prevalence of CKM syndrome stages was was 22.5% for stage 0, 23.7% for stage 1, 46.2% for stage 2, 6.7% for stage 3, and 0.94% in stage 4a and 0.03% in stage 4b. A clear, stepwise increase in MACE risk was observed with advancing stages; adjusted hazard ratios were 1.18 in stage 1, 2.02 in stage 2, 2.52 in stage 3, 5.42 in stage 4a, and 10.30 in stage 4b relative to stage 0. Kaplan–Meier survival analysis verified progressively lower event-free survival as CKM syndrome stages advanced. There was also a stepwise increase in all-cause mortality risk with advancing CKM syndrome stages, except for stage 1. Conclusion Advanced CKM syndrome stages were strongly associated with escalating MACE risk in the Korean population. These findings emphasize the need for early detection and tailored, stage-specific interventions to mitigate cardiovascular morbidity and mortality.