A SYSTEMATIC REVIEW: SYNTHETIC AND BIOLOGIC DISEASE MODIFYING ANTI-RHEUMATIC DRUGS FOR THE TREATMENT OF PSORIATIC ARTHRITIS

Purpose. To conduct a systematic review comparing the efficacy and harms of synthetic disease modifying anti-rheumatic drugs (DMARDS) and biologic DMARDs in the treatment of psoriatic arthritis (PsA).

Methods. We searched Medline from 1990 to May 2008. Abstract review, full-text review, and abstraction of data from included studies were completed independently by two reviewers.  We assessed the methodologic quality (internal validity) of included studies using predefined criteria based on the U.S. Preventive Services Task Force and the National Health Service Centre for Reviews and Dissemination (U.K.) criteria.  We limited evidence to controlled trials and systematic reviews for efficacy; we also included observational studies for adverse events. Outcomes of interest were clinical response via the ACR 20 and PASI 75, as well as adverse events.  We quantitatively evaluated the class effect of biologic DMARDs compared to placebo using a random effects model.  The other results were described qualitatively because there were insufficient numbers of similar studies for meta-analyses.

Results. We found nine publications meeting inclusion criteria.  Seven of these were controlled trials, and two were systematic reviews.  All studies compared active treatment to placebo.  There were no head-to-head studies comparing included medications.  A previously published systematic review found that both parenteral high-dose MTX and sulfasalazine improved patient outcomes compared with placebo.  One study found that leflunomide patients had better response rates and quality of life outcomes than those treated with placebo.  Meta-analysis comparing biologic DMARDs versus placebo found that the use of biologic DMARDs (adalimumab, etanercept, and infliximab) led to better outcomes than placebo.  Qualitative analysis of the harms attributed to treatments for PsA found no differences in the rate of adverse events with the following exceptions: adalimumab and etanercept treatment were associated with increased rates of injection site reactions and leflunomide can increase the likelihood of diarrhea and can lead to clinically significant increases in alanine aminotransferase.

Conclusion. The information available on efficacy and harms regarding treatments of PsA is limited and should be interpreted with care, but it appears that the use of both biologic and synthetic DMARDs may be effective treatments for PsA.  At this time there is insufficient data to conduct quantitative analyses comparing these two treatment types.