Investigating the use of the CASPAR criteria in early psoriatic arthritis
Arthritis & Rheumatism, 05/17/2012
Coates LC et al. – The CASPAR criteria are more sensitive than Moll & Wright in classifying early psoriatic arthritis (PsA). Although the sensitivity is lower than established disease, the CASPAR criteria are valid for use as inclusion criteria for early psoriatic arthritis trials.Methods
- The CASPAR criteria were applied to cases of early PsA (<24 months symptom duration) and controls with other inflammatory arthritides who were all disease–modifying anti–rheumatic drug naive.
- Gold standard diagnosis was confirmed by a consultant rheumatologist.
- Proportions of cases and controls meeting the criteria were compared using McNemars test.
- 111 early PsA cases and 111 early arthritis controls (RA n=82, undifferentiated arthritis n=13, spondyloarthritis n=9, inflamm OA n=4, crystal arthritis n=3) were recruited.
- The sensitivity of the CASPAR criteria in classifying early PsA was 87.4% compared to 80.2% for the Moll and Wright criteria.
- The specificity for both criteria was 99.1%.
- When considering different cut–points for the CASPAR criteria, the best cut–point for classification remained a score of ≥3 as in the original CASPAR analysis.
- Considering a score of ≥2 gave a higher sensitivity of 99.1% but resulted in a drop in specificity to 94.6%.
- Regression analysis identified that psoriasis and a negative RF were the most important features to differentiate PsA, followed by nail psoriasis and the presence of dactylitis.