Treatment of psoriatic arthritis and rheumatoid arthritis with disease modifying drugs -- comparison of drugs and adverse reactions.

OBJECTIVE: Rheumatoid arthritis (RA) and psoriatic arthritis (PsA) are chronic inflammatory diseases of the musculoskeletal system. Although it seems likely that these conditions have a different pathogenesis, the drugs used to treat them are the same. Our study used a cross-sectional clinical database to compare drug use and side-effect profile in these 2 diseases.
METHODS: The CASPAR study collected data on 588 patients with PsA and 536 controls, 70% of whom had RA. Data on disease modifying drug treatments used over the whole illness were recorded, together with their outcomes, including adverse events, for RA and PsA.
RESULTS: For both diseases methotrexate (MTX) was the most frequently used disease modifying drug (39% of patients with PsA, 30% with RA), with over 70% of patients in both diseases still taking the drug. Other drugs were used with the following frequencies in PsA and RA, respectively: sulfasalazine 22%/13%, gold salts 7%/11%, antimalarial drugs 5%/14%, corticosteroids 10%/17%, and anti-tumor necrosis factor (TNF) drugs 6%/5%. Compared to RA, cyclosporine and anti-TNF agents were less likely to be ineffective in PsA. Compared to RA, subjects with PsA were less likely to be taking MTX and more likely to be taking anti-TNF agents. Hepatotoxicity with MTX was more common in PsA and pulmonary toxicity with MTX was found more often in RA.
CONCLUSION: These data provide insight into prescribing patterns of disease modifying drugs in RA and PsA in a large international cohort, together with the differential adverse events of these drugs between these diseases.