Laboratory screening for side effects of disease modifying antirheumatic drugs in daily rheumatological practice

To observe the actual laboratory screening for side effects of disease modifying antirheumatic drugs (DMARDs) in daily rheumatological practice, a retrospective multi-center cohort study was performed on the laboratory tests in DMARD treated rheumatoid arthritis (RA) patients. RA patients were investigated by chart review if they started with a DMARD (cohort 1) or were treated with a DMARD for at least one year (cohort 2). Hematological, hepatic, and renal tests were collected. In cohort 1 and 2, 513 and 1209 patients were included, respectively. A fairly outlined screening profile was observed for each DMARD studied. Except for antimalarials, the testing frequency decreased with time in cohort 1. For all DMARDs the testing frequency in cohort 1 was higher than in cohort 2. In general, rheumatologists requested laboratory tests less frequently than is internationally recommended. This discrepancy raises questions about the relation between the efficacy and costs of laboratory screening for side effects of DMARDs in patients with RA.