Prognostic significance of the CALLY index for mortality among patients with cardiovascular–kidney–metabolic syndrome stages 0–3

BACKGROUND: The C-reactive protein-albumin-lymphocyte (CALLY) index integrates inflammation, nutrition, and immune status, serving as a novel, cost-effective biomarker. However, its association with mortality risk among individuals in stages 0 to 3 of the cardiovascular-kidney-metabolic (CKM) syndrome remains poorly defined. METHODS: Data from 9,886 individuals with stage 0-3 CKM syndrome in NHANES were examined. Cox proportional hazards regression, accounting for various covariates, was employed to examine the association between ln CALLY and mortality. RCS and threshold analysis were applied to investigate possible non-linear associations. Survival distributions were visualized using Kaplan-Meier curves, and additional analyses included time-dependent ROC analyses, subgroup analyses, and interaction tests. RESULTS: A strong inverse relationship was observed between ln CALLY and both all-cause mortality (HR = 0.86, 95% CI: 0.82-0.89) and cardiovascular mortality (HR = 0.81, 95% CI: 0.75-0.89). Participants in the top tertile of ln CALLY showed a 34% reduction in all-cause mortality and a 37% decline in cardiovascular mortality relative to the bottom tertile. RCS indicated a distinct L-shaped curve linking ln CALLY with all-cause mortality. Across multiple subgroups, the relationships remained stable, with no meaningful interaction effects identified. CONCLUSIONS: This analysis demonstrates that the CALLY index is inversely related to mortality in CKM stage 0-3 patients, indicating its value as a potential biomarker for early prognosis assessment.