Data from patients with rheumatoid arthritis participating in the British Society for Rheumatology Biologics Register were analyzed to determine the incidence of new-onset psoriasis in patients receiving antitumor necrosis factor alpha (TNF-alpha) (n=9,826) or traditional disease-modifying antirheumatic drugs (DMARDs) (n=2,880). Between January 2001 and July 2007, incident psoriasis was diagnosed in 25 patients treated with anti-TNF-alpha as opposed to no cases in patients treated with traditional DMARDs. Hence, the incidence rate ratio of psoriasis for patients treated with anti-TNF-alpha was 1.04 per 1,000 persons. When assessing the incidence rates of three different anti-TNF-alpha drugs used for rheumatoid arthritis, the investigators observed a significantly higher rate of new-onset psoriasis in patients given adalimumab as compared ...