Association between Neutrophil Percentage-to-Albumin ratio and anemia risk: a population-based study.

Anemia remains a significant global health challenge, driven by complex inflammatory mechanisms. This study investigated the association between neutrophil percentage-to-albumin ratio (NPAR) and anemia risk, utilizing data from 24,938 participants in the National Health and Nutrition Examination Survey (2005-2018). Multivariable logistic regression analysis revealed a significant association between NPAR and anemia risk (OR = 1.16; 95% CI 1.13-1.18, p < 0.0001). Two-piecewise regression analysis identified a nonlinear relationship with a threshold at NPAR 11.96: below this threshold, an inverse association was observed (OR = 0.88; 95% CI 0.79-0.98, p = 0.0249), while above it, a positive association was evident (OR = 1.21; 95% CI 1.18-1.25, p < 0.0001). Subgroup analyses demonstrated stronger associations in males, non-Hispanic Whites, diabetic patients, and individuals who were married or living with a partner. These findings highlight the potential of NPAR as a novel biomarker for assessing anemia risk in clinical practice.