Hemoglobin-Red Blood Cell Distribution Width Ratio (HRR) and Rheumatoid Arthritis Risk: A Population-Based Study from the NHANES

Abstract

Abstract Background: Rheumatoid arthritis (RA) is a prevalent autoimmune disease with a substantial health burden. The Hemoglobin-red cell distribution width ratio (HRR) is a novel inflammation-related biomarker, yet its association with RA risk remains unexplored. Aims: This study aimed to investigate whether HRR is independently associated with RA risk, given the lack of prior evidence on this relationship. Materials and Methods: This population-based study included 34,483 adults from the National Health and Nutrition Examination Survey database, comprising 2403 RA patients. Weighted logistic regression models and restricted cubic spline analyses were employed to examine the relationship between HRR and RA risk, adjusting for demographic and clinical covariates. Results: HRR levels were significantly lower in RA patients compared to non-RA individuals. A significant inverse, approximately linear association was observed between HRR and RA risk. Subgroup analyses showed that this relationship was modified by gender, education level, smoking and drinking status (all P for interaction <0.05). Conclusions: Lower HRR is independently associated with increased RA risk. These findings highlight HRR as a potential protective factor and provide new insights for RA risk stratification in clinical practice.