Objective: To determine the efficacy and tolerability of low dose intermittent methotrexate (MTX) in antimalarial resistant lupus arthritis.
Methods: Retrospective cohort study from the University of Toronto Lupus Clinic. Seventeen patients receiving MTX for persistently active arthritis, despite a previous therapeutic trial of antimalarial therapy, were identified. Seventeen control patients were selected who had active arthritis despite 6 months of treatment with an antimalarial agent. The primary outcome measure was a reduction in actively inflamed joint count of at least 60% over 6 months. Secondary outcome measures were the reduction in steroid dose and Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), and tolerability of MTX.
Results: Baseline characteristics including sex, race, age at diagnosis, and concomitant use of other medications were similar. Patients in the MTX group had a higher mean joint count than the control group at baseline (p = 0.003). After 6 months, 15/17 patients in the MTX group showed at least a 60% improvement in the joint count compared to only 2/17 for the control group (p < 0.001). The mean daily prednisone dose fell by 35 and 27% in the MTX and control groups, respectively (p = NS). A mean SLEDAI reduction of 0.76 was obtained in the MTX group, compared to an increase of 2.05 in the control group (p = 0.03). Over a mean followup period of 3.5 years, toxicity leading to termination was infrequent, as only 2 patients discontinued MTX due to a side effect.
Conclusion: Methotrexate appears to be effective in the treatment of antimalarial resistant lupus arthritis and is well tolerated.