Psoriatic arthritis (PsA) is a systemic, chronic inflammatory arthritis commonly associated with psoriasis and typically seronegative for rheumatoid factor. Despite numerous published classification systems—including those by Moll and Wright, Bennett, Vasey and Espinoza, Fournié, the ESSG, and the CASPAR Study Group—the absence of a universally accepted criterion has complicated efforts in epidemiological research and treatment standardization. This study audited 69 patients with PsA to evaluate which of six commonly used classification criteria were most effective in clinical practice by comparing how many patients each set successfully identified.

Of the 60 patients included in the final analysis, only 35% met all six sets of criteria. The CASPAR criteria outperformed the others, identifying 89.7% of patients who did not meet all other sets—largely due to its inclusion of family history and allowance for RF-positive cases. In contrast, Bennett’s and Moll & Wright’s criteria had significantly lower sensitivity. The study concludes that the CASPAR criteria, with their broader scope and ease of use, have strong potential as the universal standard for PsA classification, although further validation studies are recommended.

Reference: Congi L, Roussou E. Clinical application of the CASPAR criteria for psoriatic arthritis compared to other existing criteria. Clin Exp Rheumatol. 2010 May-Jun;28(3):304-10. Epub 2010 Jun 23. PMID: 20576225.