Content validity of psoriatic arthritis screening questionnaires: systematic review

Background Psoriatic arthritis (PsA) is the main entity associated with psoriasis (PsO). Consequently, several PsA screening instruments have been developed, most of them are self-administered questionnaires, known as patient-reported outcome measures (PROMs). Objective To identify, summarize, and systematically evaluate the evidence of the content validity of PsA screening PROMs, in patients with PsO, by the dermatologist, based on COSMIN methodology. Methods A structured literature search was performed, until June 2019, that included development and/or validation studies of a questionnaire for the screening of PsA in patients with PsO. The evaluation was based on the PROMs' development, relevance, comprehensiveness, and comprehensibility. Results Eleven PROMs were included in the systematic review with four additional validation studies of the included instruments. Only ToPAS2 (Toronto Psoriatic Arthritis Screen) questionnaire had an adequate content validity. CONTEST (Comparison of three screening tools to detect psoriatic arthritis in patients with psoriasis), CEPPA (Center of Excellence for Psoriasis sand Psoriatic Arthritis), and SiPAS (Simple Psoriatic Arthritis Screening questionnaire) qualified as inadequate. Conclusions Despite the existence of eleven validated PsA screening PROMs, none were supported by very high-quality evidence of their content validity, which brings the opportunity for the creation of a new proposal PROM for the screening of PsA.