Abstract
BACKGROUND: The neutrophil-percentage-to-albumin ratio (NPAR) functions as an integrative marker representing inflammatory response and nutritional health. However, its association with mortality in elderly stroke survivors has not been explored. METHODS: This cohort study analyzed data from 1,026 elderly stroke survivors in the National Health and Nutrition Examination Survey (NHANES, 1999-2018). The association of NPAR with mortality was analyzed using Cox proportional hazards regression, restricted cubic splines (RCS), Kaplan-Meier survival analysis, and time-dependent receiver operating characteristic (ROC) curves. Subgroup analyses and interaction tests were also performed. RESULTS: During the 6.65-year median follow-up, elevated NPAR showed independent associations with increased all-cause and cardiovascular mortality. Quartile-based analysis revealed 69 and 87% greater mortality hazards for the highest versus lowest NPAR groups, respectively. RCS analysis revealed a non-linear threshold effect at NPAR = 14.5, beyond which the risk of all-cause mortality increased sharply. NPAR demonstrated stable predictive accuracy, with time-dependent AUC ranging from 0.664 to 0.607 for all-cause mortality and 0.652-0.609 for cardiovascular mortality over 3-10 years. Subgroup analyses confirmed consistency across different sex, BMI, lifestyle habits, and comorbidity categories. CONCLUSION: This study underscores a strong positive correlation between NPAR and prognosis in older adult stroke survivors in the United States, indicating its potential as a novel biomarker for prognostic assessment.