Hemoglobin-to-red cell distribution width ratio and sleep duration as predictors of pneumonia: Evidence from NHANES 2011–2018

ObjectivePneumonia remains a significant global health burden; however, accessible and robust predictors of community screening are limited. This study aimed to investigate the individual and synergistic associations of the hemoglobin-to-red cell distribution width ratio-a marker of systemic inflammation-and sleep duration with pneumonia prevalence using a nationally representative sample.MethodsWe conducted a cross-sectional analysis of 39,156 adult participants from the National Health and Nutrition Examination Survey 2011-2018. To address potential selection bias from missing data, Multiple Imputation by Chained Equations (MICE) was employed to retain the full cohort. Logistic regression and restricted cubic spline analyses were used to assess independent associations. Machine learning (XGBoost) models were developed to evaluate predictive performance and feature interactions.ResultsBoth lower hemoglobin-to-red cell distribution width ratio and shorter sleep duration were significantly associated with increased pneumonia prevalence. In the fully adjusted logistic models, the association between hemoglobin-to-red cell distribution width ratio and pneumonia remained significant, although they were slightly attenuated after adjusting for metabolic comorbidities. The XGBoost model demonstrated consistent predictive performance and identified a complex nonlinear interaction between hemoglobin-to-red cell distribution width ratio and sleep duration.ConclusionsShort sleep duration independently predicts pneumonia risk, while low hemoglobin-to-red cell distribution width ratio shows a potential indirect effect through metabolic pathways. Hemoglobin-to-red cell distribution width ratio and sleep metrics may serve as accessible, low-cost markers for pneumonia screening in community populations.