Objective: To determine whether the use of antimalarials is associated with a reduction in the risk of developing rheumatoid arthritis (RA) or other connective tissue diseases in patients with palindromic rheumatism.
Methods: We conducted a retrospective cohort study based on a review of medical records to evaluate the outcome of patients with palindromic rheumatism referred to an academic center from 1986 to 1996: 113 patients complied with the selection criteria, including diagnostic criteria for palindromic rheumatism and onset of disease since 1980. After adjusting for potential confounders, Kaplan-Meier methods and Cox regression models were used to estimate the risk of developing RA or other connective tissue disease in patients who had received antimalarials compared to those who had not.
Results: Age of disease onset was 40+/-12 yrs, and mean disease duration 4.8+/-4 yrs; two-thirds of the patients were female. Sixty-two (55%) patients received antimalarials, for a mean duration of therapy of 28 mo. Thirty-three (29%) patients developed RA, 3 developed systemic lupus, and 4 developed other connective tissue diseases. Twenty (32%) patients in the antimalarial group developed a secondary disease, compared to 20 (39%) who did not receive therapy. Statistically significant differences were observed comparing time to event in both groups. The estimated median time to development of a chronic disease was 162 months in treated and 56 months in untreated patients. After adjusting for other variables in the Cox regression models, significant risk reduction in the development of a secondary disease was observed for antimalarial use (hazard ratio = 0.24; 95% CI 0.09-0.61). For RA, the risk reduction was 0.19 (95% CI 0.07-0.57). We conducted a sensitivity analysis around our censoring estimates. The risk reduction remained statistically significant, with 0.36 for RA and 0.41 for RA or other connective tissue disease.
Conclusion: Use of antimalarials in patients with palindromic rheumatism is associated with a reduction in the risk of developing subsequent RA or other connective tissue disease.