Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


HLA-Cw06 Allele Increases the Duration of Time between the Onset of Psoriasis and Psoriatic Arthritis.

Eder2,  Lihi, Chandran2,  Vinod, Pellett2,  Fawnda, Shanmugarajah2,  Sutha, Shen3,  Hua, Cook3,  Richard, Gladman1,  Dafna D.

Toronto Western Hospital, Toronto, ON, Canada
University of Toronto Psoriatic Arthritis Clinic, Toronto Western Hospital
University of Waterloo

Aim:

Most of the patients with psoriatic arthritis (PsA) develop arthritis following the onset of the skin disease, with a mean duration of approximately 7 years. It was suggested recently that the risk of developing PsA remains constant after the diagnosis of psoriasis. We aimed to investigate whether the rate of PsA after the onset on psoriasis is constant and whether it is affected by clinical and genetic factors.

Methods:

We performed a retrospective cohort analysis of patients with PsA and psoriasis without arthritis. The PsA patients were part of a large single centre longitudinal cohort. The psoriasis patients were recruited from a recently established prospective cohort of psoriasis without arthritis. They were assessed annually by a rheumatologist to rule out PsA. Only patients that developed arthritis after the onset of psoriasis were included. We analyzed the rate of PsA cases per year from the onset of psoriasis. Patients with psoriasis alone were censored at their last visit to the clinic. Parametric survival analysis was used to determine the probability model that predicts the risk of developing PsA after the onset of psoriasis. The following variables were tested for their effect on the interval of time from psoriasis to PsA: HLA-C*06, HLA-B*27, gender, type I vs. II psoriasis.

Results:

438 patients with psoriasis and 769 patients with PsA were included in the study. The mean age at onset of psoriasis and PsA were 26.8±14.7 and 37.3±13.3 years. The sex ratio was 1.3:1 (male: female). The proportion of type I psoriasis was 82.8%. 36% of the participants were carriers of HLA-Cw*06 allele and 11% of the participants were carriers of HLA-B*27 allele. The mean time from the onset of psoriasis to development of PsA was 12.2±10.7 years. The estimated annual probability of PsA was fit with an exponential probability model, suggesting that the risk of developing PsA over time was constant. Tests for trend did not suggest any evidence of departure from a constant hazard. HLA-Cw*06 carriers were associated with longer intervals of time between psoriasis and development of PsA (Relative Risk 0.54, 95% Confidence Interval 0.37–0.78, p=0.001). HLA-B*27, type of psoriasis and gender were not found to affect the time interval between psoriasis and PsA.

Conclusions:

The risk of developing PsA over time among psoriasis patients is constant. HLA-Cw*06 allele doubles the duration of time between the onset of psoriasis and PsA.

To cite this abstract, please use the following information:
Eder, Lihi, Chandran, Vinod, Pellett, Fawnda, Shanmugarajah, Sutha, Shen, Hua, Cook, Richard, et al; HLA-Cw06 Allele Increases the Duration of Time between the Onset of Psoriasis and Psoriatic Arthritis. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :530
DOI: 10.1002/art.28299

Abstract Supplement

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