Measuring psoriatic arthritis symptoms: A core domain in psoriasis clinical trials

Background: The International Dermatology Outcome Measures established a set of core domains to be measured in all psoriasis trials. This set requires that symptoms of psoriatic arthritis (PsA) be measured in all psoriasis studies. Objective: To identify the approach to PsA screening and the most appropriate outcome measure for capturing PsA symptoms. Methods: Following guidelines (ie, the COnsensus-based Standards for the selection of health Measurement INstruments, Core Outcome Measures in Effectiveness Trials Initiative, and Outcome Measures in Rheumatology Handbook), we conducted a consensus-building study that included patients, physicians, industry partners, and patient association representatives. The process consisted of a literature review and quality appraisal of measures for PsA symptoms, a pre-Delphi exercise, a Delphi survey, and a consensus meeting. Results: Among the 297 expert participants in the Delphi survey, 87.5% agreed that all patients in a psoriasis trial should be screened for PsA with a validated screening tool. Regarding the measurement of PsA symptoms, the preferred instrument was the Psoriatic Arthritis Impact of Disease-9 (PsAID9), with the Routine Assessment Patient Index Data-3 (RAPID3) representing an acceptable alternative. Limitations: Only International Dermatology Outcome Measures members participated in the consensus meeting. Conclusion: The overwhelming majority of expert stakeholders agreed that all psoriasis trial participants should be screened for PsA, with PsA symptoms measured by using PsAID9 (or alternatively with RAPID3).