A case-control study of anaemia in patients with rheumatoid arthritis treated with disease-modifying antirheumatic drugs in an adult population in the US: Prevalence and impact on healthcare utilisation

Abstract

Objective: The objective of this study was to estimate the prevalence of anaemia and its impact on healthcare utilisation in patients with rheumatoid arthritis (RA). Methods: Patients with claims for moderate-to-severe RA (ICD-9 code 714.x) treated with disease-modifying antirheumatic drugs as well as controls without RA matched for age, gender and time in plan were selected from the MarketScan Research Database. Anaemia was identified by ICD-9 codes 280.x, 285.2x, 281.9, 285.9 and 284.8. The prevalence ratio and 95% confidence interval (CI) for anaemia among RA patients versus controls were estimated. Overall disease burden was measured using the Elixhauser Comorbidity Index (ECI). Results: The prevalence ratio for anaemia in RA patients was 2.2 (95% CI 2.1-2.4). Mean ECI was higher in RA (2.26) compared with control (1.02) patients (p<0.001), and RA patients with anaemia had a higher ECI compared with those without anaemia (3.95 vs. 2.08; p<0.001). Total healthcare costs in RA patients with anaemia were approximately twice those of RA patients without anaemia. Conclusions: The prevalence of clinically diagnosed anaemia in RA patients in the claims database was 2.2 times higher than that in the comparable non-RA control group. RA patients with anaemia had significantly higher levels of co-morbidity and healthcare costs than RA patients without anaemia. © 2008 Informa UK Ltd.