PREVALENCE OF PSORIATIC-ARTHRITIS IN ITALIAN PSORIATIC PATIENTS

Objective. To evaluate the prevalence of psoriatic arthritis (PsA) in Italian patients with psoriasis and to compare the Moll and Wright cri teria, the European Spondylarthropathy Study Group (ESSG) criteria, an d Amor criteria when applied to this patient population. Methods. We e xamined 205 unselected patients with psoriasis. The diagnosis of PsA w as based upon the clinical experience of a rheumatologist. After, we t ested these classification criteria. HLA class I and II antigens were also analyzed. Results. Thirty-six percent (75) of psoriatic patients were considered by a clinical expert to have PsA. Moll and Wright crit eria identified 46 patients (22%) with PsA; 49 patients (24%) were ide ntified by ESSG criteria and Amor criteria; 12 patients identified by Amor criteria but not by ESSG criteria presented enthesitis or dactyli tis; 10 patients identified by ESSG but not by Amor criteria had perip heral synovitis. In patients with peripheral arthritis and psoriasis, the evaluation of NSAID response was critical to fulfilling Amor crite ria. However, it was not easy to retrospectively evaluate NSAID respon se using these criteria. The sensitivity was low for each of the 3 cla ssification criteria (from 61 to 65%), whereas the specificity was hig h (from 99 to 100%). Conclusion. Our study confirms a high prevalence of PsA among an unselected population of Italian patients with psorias is. Our data reveal the inadequacy of the existing criteria for PsA, i ncluding the ESSG criteria and Amor criteria for the classification of spondyloarthropathy.