Objective: To compare the efficacy and toxicity of methotrexate (MTX) and intramuscular (im) gold in the treatment of psoriatic arthritis (PsA).
Methods: Medical records from all patients with PsA attending the gold and MTX clinics at the Vancouver Mary Pack Arthritis Centre between 1971 and 1995 were reviewed. The odds of a clinical response (defined as at least a 50% reduction in active joint count from initial to last visit or for at least 6 months) and the relative risk of discontinuing therapy associated with treatment (MTX or im gold) were calculated after controlling for significant baseline covariates, using logistic regression and Cox regression analyses, respectively. The frequency of side effects and the reasons for treatment cessation were also compared between treatment groups.
Results: Eighty-seven patients received 111 treatment courses: 43 of MTX and 68 of im gold. The likelihood of a clinical response was 8.9 times greater (95% CI 1.8; 44.0) with MTX than im gold. Patients were 5 times more likely (95% CI 2.4; 10.4) to discontinue therapy with im gold than with MTX. No major toxicity occurred and frequency of side effects was similar for both treatments. Patients with a longer duration of PsA prior to initiation of study treatment were less likely to achieve a clinical response.
Conclusion: MTX and im gold are safe and well tolerated in the treatment of PsA. In our experience. MTX was superior to im gold in the likelihood of achieving a clinical response and in permitting an individual to continue longterm treatment. Our data suggest that earlier treatment may be associated with a better response.