Sensitivity of the classification of psoriatic arthritis criteria in early psoriatic arthritis.

Abstract

To determine the sensitivity of the CASPAR criteria in patients with early psoriatic arthritis (PsA). Consecutive patients with a clinical diagnosis of PsA and a disease duration < 12 months were enrolled for study. The proportion of patients meeting the criteria (i.e., the sensitivity) was determined. Forty-four patients with early PsA (23 women, 21 men; mean age 51 yrs, range 16-90) were enrolled. Mean disease duration (+/- SD) was 15.8 +/- 14.3 weeks (range 0.1-50.9 wks). Thirty-four patients satisfied the criteria at the first visit (sensitivity 77.3%). Most patients met the skin and laboratory criterion, i.e., they were rheumatoid factor-negative, while only 2 satisfied the radiologic criterion. Our findings suggest a less satisfactory performance of the CASPAR criteria when applied in early PsA. Lower sensitivity could mainly depend on the small proportion of patients fulfilling the radiologic criterion.