The classification for psoriatic arthritis (CASPAR) criteria -- A retrospective feasibility, sensitivity, and specificity study
The Journal of Rheumatology, 11/28/2011
Clinical Article
Tillett W et al. – This study demonstrates that the feasibility, specificity, and sensitivity of the CASPAR are maintained when adapted for retrospective use to classify an established research cohort.
Methods- 480 patient records were reviewed from the Royal National Hospital for Rheumatic Diseases Psoriatic Arthritis (PsA) cohort and for 100 consecutive controls with inflammatory arthritis from a general rheumatology clinic
- The CASPAR score was modified for retrospective use; both “inflammation” and “current psoriasis” were recorded as present if they had ever been confirmed in the rheumatology clinic
- Sensitivity and specificity of CASPAR criteria were compared with expert clinical diagnosis
- 480 database records were identified
- 9 sets of records had been lost or destroyed
- Diagnoses had changed in 15 cases, which were transferred to the control arm, leaving 456 patients with an expert diagnosis of PsA
- Of 115 controls, 96 had RA, 5 OA, 3 reactive arthritis, 3 seronegative arthritis, 3 undifferentiated arthralgia, 2 ankylosing spondylitis, 1 spondyloarthritis, and 2 systemic sclerosis
- Sensitivity (99.7%) and specificity (99.1%) were both high and equivalent to previous reports
- Sensitivity remained high even after inclusion of 7 PsA patients with insufficient data to complete the CASPAR assessment (sensitivity 98.2%, specificity 99.1%)
- Criteria were found to be easy and practical to apply to case records



