Association Between Socioeconomic Status and Mortality Risk in CKM Stage 0-3 Patients: Analysis of Inflammatory Mediation.

Objective: This study aimed to investigate whether socioeconomic status (SES) influences the risk of all-cause and cardiovascular mortality among patients with cardiovascular-kidney-metabolic (CKM) syndrome stages 0-3 through the systemic inflammation response index (SIRI). The investigation utilized a nationally representative sample from the U.S. National Health and Nutrition Examination Survey (NHANES) database and employed mediation analysis for systematic assessment. Methods: Data were derived from NHANES surveys conducted between 1999 and 2018, enrolling adults who met the classification criteria for CKM stages 0-3. SES was defined by the stratified family income-to-poverty ratio (PIR), with SIRI serving as the mediator. The primary outcomes were all-cause and cardiovascular mortality. Methodological approaches included weighted multivariable Cox regression, subgroup analyses, sensitivity analyses, and bootstrap-based mediation analysis. Results: The study included 15,623 participants who were followed for a mean duration of 115 months, during which 1788 all-cause deaths and 405 cardiovascular deaths were recorded. After comprehensive adjustment for potential confounders, each unit increase in PIR was associated with a significantly reduced risk of all-cause mortality (HR = 0.88, 95% CI: 0.84-0.92) and cardiovascular mortality (HR = 0.85, 95% CI: 0.77-0.95). Participants in the high SES group demonstrated substantially lower risks for both all-cause mortality (HR = 0.57, 95% CI: 0.47-0.69) and cardiovascular mortality (HR = 0.50, 95% CI: 0.34-0.73) compared to their low SES counterparts. Notably, mediation analysis revealed that SIRI accounted for 63.67% of the association between SES and all-cause mortality, and 60.45% of the association between SES and cardiovascular mortality after full adjustment for confounding variables. Conclusion: SES significantly impacts the risk of all-cause and cardiovascular mortality among patients with CKM stages 0-3, with a substantial portion of this effect mediated through systemic inflammation as measured by SIRI. These findings suggest that comprehensive interventions targeting both socioeconomic conditions and chronic inflammation may effectively enhance long-term health outcomes in this vulnerable population.