Five-year outcome of a primary-care-based inception cohort of patients with inflammatory polyarthritis plus psoriasis

OBJECTIVES: To establish whether patients with inflammatory arthritis plus psoriasis have a different outcome from those who do not have psoriasis. METHODS: Seventy-nine patients with inflammatory arthritis plus psoriasis were recruited by the Norfolk Arthritis Register (NOAR) in 1990-94 and followed for 5 yrs. Their outcome was compared with the remainder (n = 755) of the NOAR cohort. We then restricted the analysis to subjects who were rheumatoid factor (RF)-negative, and compared those with and without psoriasis. Outcomes studied included remission, deformed joint count, the presence and extent of erosive damage and physical function. RESULTS: Patients with psoriasis were younger, more likely to be male, less likely to be RF-positive and more likely to have been treated with disease-modifying drugs than patients without psoriasis. After adjustment for age, gender and treatment, the only differences between the psoriasis and non-psoriasis groups were in RF positivity (adjusted odds ratio 0.44; 95% CI 0.25, 0.78) and in the Larsen score in patients with erosions. CONCLUSIONS: Patients with inflammatory arthritis plus psoriasis have a similar outcome to other RF-negative patients with arthritis.