Patients with newly diagnosed psoriatic arthritis (PsA) receiving methotrexate (MTX) have similar retention rates and switching to other disease-modifying antirheumatic drugs (DMARDs) as patients with newly diagnosed with rheumatoid arthritis (RA), according to study findings published in Rheumatic & Musculoskeletal Diseases Open.
Study authors compared the percentage of patients with newly PsA) and RA who continued receiving treatment with MTX, irrespective of any changes to other DMARDs within 2 years of starting treatment. They also compared the percentage of patients who did not receive any other DMARDs after discontinuing MTX. The effectiveness of methotrexate treatment was also evaluated.
In an observational study, prospective data were collected from national healthcare registers in Sweden, and cases of PsA and RA were identified using the International Classification of Diseases codes in the National Patient Register. Clinical data on disease activity measures and dispensation of prescriptions were collected from the Swedish Rheumatology Quality register and the Prescribed Drugs Register, respectively.
Patients with PsA were matched 1:1 with patients with RA based on sex, age, year of initiation of MTX, and region of residence. The follow-up period began when the first dose of MTX was dispensed and ended at the occurrence of the primary or secondary outcome, death, diagnosis of PsA in patients with RA, or the end of the study on December 2021.
Patients with RA had higher counts of swollen and tender joints, higher disease activity scores, and higher median C-reactive protein (CRP) levels, and worse evaluator-assessed disease activity.
At the 6 months, researchers found that 26% of patients with PsA compared with 36% of patients with RA achieved pain scores of 15 mm or lower. A total of 32% of patients with PsA compared with 42% of patients with RA achieved global health scores of 20 mm or lower. Patients with PsA had a rate of 20% of evaluator-assessed remission, compared with 27% among patients with RA.
After 2 years of MTX initiation, 71% of patients with PsA vs 76% of patients with RA continued to receive MTX. Similarly, 66% of patients with PsA vs 60% of patients with RA did not receive initiation with any other DMARD.
A limitation of the study included the limited information in the registers about PsA features except joint disease, making it challenging to compare with other studies. In addition, comparisons were hindered due to the lack of a control group.
Lindström U, di Giuseppe D, Exarchou S, et al. Methotrexate treatment in early psoriatic arthritis in comparison to rheumatoid arthritis: an observational nationwide study. RMD Open. 2023;9(2):e002883. doi:10.1136/rmdopen-2022-002883