Psoriatic arthritis: a quantitative overview of therapeutic options. The Psoriatic Arthritis Meta-Analysis Study Group.

The objective of this study was to use the technique of meta-analysis to undertake a systematic review of published and unpublished randomized controlled trials of pharmacological agents to determine their relative efficacy and toxicity in the treatment of psoriatic arthritis. The main outcome measure was the change in pooled disease index with component variables derived from OMERACT. Nineteen randomized trials were identified, of which 12 were included in the quantitative analysis with data from 792 subjects. Although all agents were better than placebo, parenteral high-dose methotrexate, salazopyrin, azathioprine and etretinate were the agents that achieved statistical significance (although it should be noted that only one component variable was available for azathioprine and only one trial with a high dropout rate was available for etretinate suggesting some caution is necessary in interpreting these results). In all trials, the placebo group improved over baseline (pooled improvement 0.43 disease index (DI) units, 95% CI 0.28-0.59). There were insufficient data to examine toxicity. In conclusion, parenteral high-dose methotrexate and salazopyrin are the only two agents with well-demonstrated published efficacy in psoriatic arthritis. The magnitude of the effect seen with etretinate, oral low-dose methotrexate, azathioprine and perhaps colchicine suggests that they may be effective, but that further multicentre clinical trials are required to establish their efficacy. Furthermore, the magnitude of the improvement observed in the placebo group strongly suggests that uncontrolled trials should not be used to guide management decisions in this condition.