The National Health and Nutrition Examination Survey

All analyses accounted for NHANES sample weights, clustering, and stratification. We used EmpowerStats (v4.1, www.empowerstats.com) and R software (v4.4.1, www.r-project.org). Continuous variables were expressed as weighted mean ± standard error (SE), and categorical variables as weighted percentages. Associations between the CALLY index and all-cause mortality were assessed using Cox proportional hazards models. Model 1 was the unadjusted crude model. Model 2 included adjustments for age, sex, race, BMI, PIR, education, smoking, and alcohol consumption. Model 3 was the fully adjusted model including additional covariates, HDL, TC, BUN, uric acid, SCR, physical activity, energy intake, hypertension, CVD. Kaplan-Meier survival curves were used to compare survival across CALLY quartiles; differences were assessed using log-rank tests. Nonlinear associations were examined with smoothed curve fitting. Subgroup analyses explored consistency across strata. ROC curves and AUC were used to compare the predictive performance of CALLY, SII, PLR, and NLR. P < 0.05 was considered statistically significant.