Objectives: To examine whether or not earlier therapeutic intervention with methotrexate (MTX) prevents the development of rheumatoid arthritis (RA) in patients with recent-onset undifferentiated arthritis (UA) showing high anti-citrullinated peptide antibody (ACPA) titers.
Methods: The patients were divided into two groups, one was treated with MTX (MTX+ group, n = 29), and the other was treated without MTX (MTX- group, n = 19), and other disease-modifying anti-rheumatic drugs were not permitted in the two groups before the primary endpoint was met. The primary endpoint is the occurrence of definite RA, and it was compared in the two groups after 1 year.
Results: The percentage of patients who developed definite RA in the MTX+ group (17.2%) was significantly lower than that in the MTX- group (78.9%) (log-rank test, P < 0.001, n = 48); adjusted hazards ratio: 0.028 [95% confidence interval (CI): 0.003-0.250, P = 0.001, n = 39]. Treatment effectiveness was not decreased by major risk factors of RA onset such as smoking habits and human leukocyte antigen-DRB1 shared epitope (SE) (smoking habit, odds ratio [OR]: 0.041 [95% CI: 0.007-0.246] P < 0.001; SE, OR: 0.022 [95% CI: 0.002-0.204] P < 0.001). The safety issues were comparable between the two groups.
Conclusions: This suggests that early therapeutic intervention with MTX could safely prevent the development of RA in patients with recent-onset UA showing high ACPA titers.
Keywords: Anti-citrullinated peptide antibody; Methotrexate; Recent-onset undifferentiated arthritis; Rheumatoid arthritis.