Background Rheumatoid arthritis (RA) is a common autoimmune disease, characterized by cartilage and bone destruction, autoantibody production and systemic disorders. (1) One of the most common comorbidities is anemia, caused by chronic inflammation or iron deficiency, with an high impact on quality of life. (2)
Objectives According to older literature, the prevalence of anemia in RA patients is between 30 and 66%. (3) In a study cohort witch was designed to evaluate iron metabolism in chronic inflammation, we found lower prevalence. Therefor we investigated the actual prevalence of anemia in RA outpatients at our tertiary center at routine follow up in 2014 and at initial diagnosis. We also looked for the impact of disease activity and therapy strategies on the prevalence of anemia and hemoglobin levels.
Methods We retrospectively analysed RA outpatients. As far as available, laboratory parameters, disease activity (CDAI, DAS28) and drug therapy were collected at the time of initial diagnosis and at a routine follow-up. Until now we included 305 patients. Anemia was defined as hemoglobin <120 mg/dl in women, and <130 mg/dl in men. Wilcoxon or Mann-Whitney-U-test was performed to compare subgroups, Spearman-Rank-Analysis was applied to analyse correlations.
Results 305 RA patients, with a mean disease duration of 11,3 years, were analyzed. Data of patients at initial diagnosis were only available after 2000. Prevalence of anemia at initial diagnosis was 15,9% and declined at follow up in 2014 to 11,45%. Anemia was significantly linked to more advanced inflammation as evidences by a significant correlation between ESR, CRP and hemoglobin levels at these time points and associated with a reduced MCV and MCH. Overall, patients showed a significant increase of hemoglobin levels upon treatment. Among patients receiving biological treatment in 2014 (n=122) 13,9% were anemic, with no difference between the biological agents. DMARDs (disease modifying anti-rheumatic drugs) were not inferior to biological treatment regarding the prevalence of anemia and hemoglobin levels.
Conclusions The prevalence of anemia in RA patients appears nowadays to be significantly lower as previously described (3). This may be due to an earlier diagnosis of RA along with an overall better disease control with modern therapy strategies. Hemoglobin levels significantly increase under therapy in all patients, anemic or not. DMARDs are, in regard to the prevalence of anemia and hemoglobin levels not inferior to biologicals. Even under good disease control as seen in our patients, the prevalence of anemia in RA patients is about twice as high as in the general population (4). This is an interims report of a registry to systemically study and characterize anaemia in Austria along with the evaluation of the impact of anemia on the course of RA.
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Disclosure of Interest None declared