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.

High Prevalence of Psoriatic Arthritis in a Psoriasis Patients Cohort.

Khraishi2,  Majed M., Newhook1,  Trevor, Landells3,  Ian, Mong3,  Jonathan, Aboushehde,  Kassem

Nexus Clinical Research, St. Johns, NL, Canada
Nexus Clinical Research, St Johns, NL, Canada
Nexus Clinical Research


The prevalence of PsA is reported to range from 5 to 40% in individuals with psoriasis. We set out to detect the prevalence of PsA in psoriasis patients seen in a dermatology practice and define their characteristics utilizing a validated self-administered screening questionnaire, PASQ (the Psoriatic Arthritis Screening Questionnaire)


Patients with definite Plaque psoriasis (as determined by the dermatologist) completed the PASQ, a validated screening tool which has an optimal cut-off of 9 in established PsA. To ascertain that all patients with PsA are captured, we chose a lower cutoff point of 7 on the questionnaire. All patients scored 7 and higher on the PASQ were assessed by a rheumatologist to ascertain the diagnosis of PsA according to the CASPAR criteria. Epidemiological, clinical and laboratory parameters were recorded in addition to the score of the PASQ. Statistical analyses were performed utilizing SPSS 17.0.


Sixty six patients consecutive patients with confirmed diagnosis of psoriasis who were seen by the dermatologist were enrolled. The mean age (SD) was 45.6 (13.5) years, 30 (45.5%) were females. Average duration of psoriasis was 12.4 (10.1) years. 28 (42.4%) of the patients had baseline PASQ scores of 7 or higher and 17 of those patients were assessed by a rheumatologist where 12 were determined to have definite PsA, three had osteoarthritis, one had undifferentiated synovitis and one had ankylosing spondylitis. Of those 38 patients with a PASQ < 7, five had definite diagnosis of PsA which was reconfirmed by the rheumatologist resulting in 17 patients with PsA in this cohort. Assuming none of the remaining patients were later diagnosed with PsA, the prevalence of psoriatic arthritis in our psoriasis cohort is 25.8%. This would be an underestimate of the true prevalence since 11 of the patients with a PASQ >= 7 had not yet been assessed by a rheumatologist yet.

Khraishi et. al.11 determined that when using the PASQ as a screening tool on patients with early PsA (mean symptoms duration of 12 months) a cut-off point of greater or equal to 7 yielded a sensitivity and specificity of 82% and 75%, respectively. If the sensitivity is applied to those 11 patients with a PASQ >= 7that were not seen by a rheumatologist, approximately 9 (11*0.82) of these patients should eventually be diagnosed with PsA(assuming they have early PsA). This will result in a total of 26 PsA patients indicating that the estimated prevalence (95% CI) of PsA in patients with psoriasis is 39.4% (27.6%, 51.2%) in a dermatology setting.


Our estimated prevalence of PsA in psoriasis patients from a population of patients drawn from a dermatology practice is larger than most prior estimates. This fact illustrates the importance of screening for PsA in psoriasis patients as this comorbidity may affect the course of treatment and if left untreated may have a profound effect on the disability and quality of life of a large number of psoriasis patients.

To cite this abstract, please use the following information:
Khraishi, Majed M., Newhook, Trevor, Landells, Ian, Mong, Jonathan, Aboushehde, Kassem; High Prevalence of Psoriatic Arthritis in a Psoriasis Patients Cohort. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1939
DOI: 10.1002/art.29704

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