Does Anemia Independently Influence the Erythrocyte Sedimentation Rate in Rheumatoid Arthritis? A Multivariate Analysis From North India

BACKGROUND: In regions such as North India, where anemia is prevalent, interpretation of the erythrocyte sedimentation rate (ESR) in rheumatoid arthritis (RA) may be challenging. We evaluated the independent associations of inflammation, autoantibody status, and anemia with ESR elevation and examined morphologic anemia patterns in this cohort. METHODS: We conducted a retrospective cross-sectional analysis of 152 RA patients attending a tertiary care center. Multivariate logistic regression identified independent predictors of elevated ESR and of anemia after adjustment for covariates. Seropositivity was defined by rheumatoid factor (RF) or anti-cyclic citrullinated peptide (anti-CCP) positivity. Among anemic patients, anemia was classified morphologically as microcytic or normocytic based on mean corpuscular volume (MCV), and inflammatory markers were compared across groups. Missing laboratory data were addressed using multiple imputation by chained equations (MICE). RESULTS: The cohort was predominantly female (133/152, 87.5%), and seropositive RA accounted for 75.7% (115/152) of cases. In the ESR model, C-reactive protein (CRP) positivity was the strongest independent predictor (adjusted odds ratio [aOR] 7.81, p