Background Several classification criteria for Psoriatic Arthritis (PsA) have been proposed, being CASPAR criteria the most accepted at present. Recently ASAS has proposed classification criteria for patients with axial and peripheral spondyloarthritis, which have not been assessed in patients with psoriasis.
Objectives To determine the prevalence of PsA according to CASPAR criteria, and to compare such prevalence with that resulting from the use of ASAS peripheral and axial criteria, and New York criteria for AS.
Methods The first 100 patients that consecutively attended a Psoriasis clinic of a Dermatology Service were assessed. Demographic and clinical data were collected, and all patients were questioned and examined by a rheumatologist for joint manifestations. In all cases, rheumatoid factor was determined and radiographies of hands, feet, cervical spine and pelvis for sacroiliac joints were obtained. All X-rays were read independently by two observers in blind fashion. Patients with objective joint manifestations, both axial and peripheral, were considered to fulfill CASPAR, ASAS peripheral and axial, and New York criteria. Correlations were calculated by Spearman’s test. Categorical variables were compared by x2, and continuous variables were compared by Student’s test
Results Of the 100 patients included(62 males), median age was 48 years and median duration of psoriasis of 11 years. 93% of patients presented psoriasis vulgaris, and 56% nail involvement. Seventeen patients had peripheral arthritis, mono or oligoarticular in 9 and polyarticular in 8. Median time of arthritis duration was of 8 years. Seven patients had chronic neck pain while 6 had chronic back pain. 13 patients had cervical limitation and 6 patients lumbar limitation. Radiographic sacroiliitis grade 2 and 3 was fiund in 12% of patients, and grade 4 in 2%, being symmetric in 7% of patients. At a cervical level, 10 patients had syndesmophytes whereas 3 had interapophyseal ankylosis. Of all patients, 17% fulfilled CASPAR and ASAS peripheral criteria, 6% New York and 5% ASAS axial criteria. Patients who met CASPAR criteria showed significantly higher time of psoriasis duration compared to those without arthritis (m 16 vs 10 years p=0.02), and a higher frequency of nail disease (88.2% vs 49.4% p=0.003). Five patients (29.4%) fulfilled ASAS axial criteria; all of them had peripheral involvement: mono/oligoarticular in 3 and polyarticular in 2 patients. Patients with peripheral and axial involvement presented a significantly higher frequency of erythrodermic psoriasis compared to the other patients (35.3% vs 1.2% p=0.0006 and 80% vs 16.7% p=0.02). Among the 95 patients without ASAS axial criteria, 9 showed sacroiliitis grade 2 or higher. Among the 83 patients without arthritis, only 1 presented peripheral radiological changes, whereas 5 presented sacroiliitis grade 2 or 3
Conclusions Prevalence of PsA, for both CASPAR and ASAS peripheral criteria, was 17%. According to ASAS criteria, 5% of patients presented axial involvement, while 6% had axial involvement according to New York criteria. All cases with arthritis presented a higher frequency of nail involvement and skin severity. It is worth noting that few patients without signs or symptoms of arthritis presented radiological changes, both axial and peripheral, avoiding a proper classification.
Disclosure of Interest None Declared
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