The Journal of Rheumatology 2003; 30:5 1022 2002-427-1 From the University of Toronto Psoriatic Arthritis Clinic, Centre for Prognosis in the Rheumatic Diseases, Toronto Western Hospital, Toronto, Ontario, Canada. Supported by grants from The Arthritis Society and the Canadian Institutes for Health Research. M. Khan was supported by a CIHR Burroughs Wellcome Fund Student Research Award. M. Khan, Medical Student, University of Toronto; C. Schentag, BSc, Research Associate, Psoriatic Arthritis Program; D.D. Gladman, MD, FRCPC, Professor of Medicine, Director, Psoriatic Arthritis Program, Deputy Director, Centre For Prognosis Studies in the Rheumatic Diseases, University Health Network, Toronto Western Hospital. Address reprint requests to Dr. D. Gladman, Centre for Prognosis Studies in the Rheumatic Diseases, Toronto Western Hospital, EC-5-0348 399 Bathurst Street, Toronto, Ontario M5T 2S8. E-mail: dafna.gladman@utoronto.ca Submitted April 23, 2002; revision accepted November 8, 2002. The first description of an association between arthritis and psoriasis was published in 1818, but Wright first suggested that a particular form of arthritis was associated with psori- asis 1 . Initially thought of as an alternate form of rheumatoid arthritis (RA), the distinction between psoriatic arthritis (PsA) and RA was confirmed when it was discovered that the majority of patients with PsA were seronegative for rheumatoid factor. Furthermore, epidemiological evidence supports the notion of PsA as a distinct clinical entity. The frequency of arthritis among psoriatic patients varies from 7 to 42%, whereas in the general population its prevalence is 2 to 3% 1 . The prevalence of psoriasis in the general popula- tion is 0.1 to 2.8%, whereas it is 2.6 to 7.0% in arthritic patients 1,2 . Clinical features also differentiate PsA from other forms of arthritis, specifically osteoarthritis and RA 1 . Initially considered to be a disease with a benign course, studies have shown that PsA can be a progressive, deforming, and occasionally mutilating arthritis. PsA has been shown to lead to joint damage and disability in 20% of patients 3 . In a 5 year followup study, the number of patients with at least 5 damaged joints increased from 19 to 41% 4 . It was also found that 57% of patients with PsA had an erosive form of arthritis in a study of 180 patients 5 . Due to the potential devastating consequences of the disease, it should be recognized promptly. Several patterns of PsA were recognized by Moll and Wright 6 . These include: (1) arthritis of the distal interpha- langeal joints only; (2) oligoarthritis, often asymmetric and affecting less than 5 joints; (3) polyarthritis, often symmet- rical and indistinguishable from RA, affecting more than 5 joints; (4) destructive (mutilans) arthritis; and (5) spondy- loarthropathy (SpA) usually associated with peripheral arthritis. Currently, however, a valid and widely accepted diag- nostic or classification criteria set for PsA does not exist. The difficulty in establishing criteria is due to the different frequencies of pattern distribution seen in PsA patient popu- lations. This is likely because patients may change their pattern of disease over time. For example, patients may begin with an oligoarthritis pattern, and then change to polyarthritis during the course of their disease. SpA may Clinical and Radiological Changes During Psoriatic Arthritis Disease Progression MUSTAFA KHAN, CATHERINE SCHENTAG, and DAFNA D. GLADMAN ABSTRACT. Objective. To determine the contribution of radiological findings at the initial visit with respect to classifying patients with psoriatic arthritis (PsA); and to determine the extent to which the clinical disease patterns change over time. Methods. Patients with PsA were followed prospectively at 6–12 month intervals since 1978; 86 patients were registered within 1 year of diagnosis and were followed for at least 1 year. Based on the clinical information, including the actively inflamed joint count, damaged joint count, and the presence of back disease and arthritis mutilans, a clinical PsA pattern was assigned. A separate radi- ology pattern based on radiographs alone, and a combined clinical and radiological pattern, was also assigned at each visit. The initial clinical pattern was compared to the initial combined clinical-radi- ological pattern, and the initial clinical pattern was compared to the clinical pattern at 1 year and 5 years in 35 patients with both 1 and 5 year followup. Results. In 23% of the patients, the radiological assessment in the initial visit showed evidence of patterns not detected clinically; 49% and 77% of the patients showed clinical pattern change within 1 year and 5 years, respectively. A comparison between the group that changed pattern and the one that did not change pattern in 5 years revealed no significant features. Conclusion. Radiological assessments add information not gained from clinical assessment alone. Clinical patterns do change over time in the majority of patients. Both elements must be taken into consideration when developing classification criteria for PsA. (J Rheumatol 2003;30:1022–6) Key Indexing Terms: PSORIATIC ARTHRITIS PROGNOSIS RADIOLOGY CRITERIA Personal, non-commercial use only. The Journal of Rheumatology Copyright © 2003. All rights reserved. www.jrheum.org Downloaded on January 10, 2022 from