FRI0674 Applicability of the psaid12 questionnaire as a core outcome measurement in psa clinical trials: an evaluation using omeract filter 2.1 instrument selection criteria
Authors: R. Holland, P. Højgaard, B. Shea, D. Beaton, P. Tugwell, M. de Wit, W. Tillett, R. Christensen, N. McHugh, P. Mease, A.-M. Orbai
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background:</h3> The Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA)–Outcome Measures in Rheumatology (OMERACT) Psoriatic Arthritis (PsA) Core Set working group is in the process of selecting core outcome measurements for PsA randomised trials, following OMERACT Filter 2.1 for instrument selection<sup>1</sup>. The Psoriatic Arthritis Impact of Disease questionnaire (PsAID12) passed the first two steps (domain match and feasibility) at the GRAPPA 2017 annual meeting and is a candidate instrument to measure PsA specific health related quality of life (HRQOL)/Life impact. <h3>Objectives:</h3> To conduct a systematic review (SR) of the PsAID literature to review the measurement properties in the OMERACT Filter 2.1, assess specifically construct validity (truth) and discrimination of the PsAID12 questionnaire based on available evidence, and to identify gaps in knowledge that need to be covered in order for PsAID12 to pass Filter 2.1. <h3>Methods:</h3> A SR of PsA patient reported outcomes (PROs) was performed January 1 2017 and updated by hand search (22/11/2017). All articles assessing the measurement properties of the PsAID12 were reviewed. Strength of evidence was rated using COSMIN-OMERACT Good Methods checklist, and performance of measurement properties using the OMERACT standards<sup>1</sup>. We extracted data on domain match (face and content validity), construct validity, test-retest reliability, longitudinal construct validity, clinical trials discrimination, and thresholds of meaning. <h3>Results:</h3> We identified six studies (129–474 patients in each study) assessing the measurement properties of the PsAID12 in adults with PsA. Domain match: PsAID12 was developed with 12 patient research partners, 139 patients who ranked domain importance and cognitive interviews with 65 patients. Construct validity: Three studies assessed correlation of the PsAID12 with PROs and clinical outcomes, and one study with two PROs. There was strong correlation with measures of function (n=3 studies, r&gt;0.66), participation (1, r&gt;0.69), disease activity (2, r=0.64–0.87), and measures of pain, fatigue and stiffness (1 each, r&gt;0.83); moderate-strong with patient and physician global (3, r=0.49–0.84); and moderate with 66/68 joint counts (1, r=0.4–0.57) and dactylitis (1, r=0.49). Test-retest reliability was high (0.91 (95%CI 0.87–0.94) and 0.95 (0.92–0.96)). Longitudinal construct validity was good with moderate to large standardized response mean (SRM) 0.74 (n=53, changed therapy) and 0.91 (n=71, changed therapy and rated themselves improved). The patient acceptable symptom state (PASS) was 4 in a single study. The minimal clinically important improvement (MCII) varied between 3 (original PsAID development study) and 1.25 (subsequent UK study). <h3>Conclusions:</h3> This review suggests there is evidence for excellent content validity and reliability and good construct validity and responsiveness of the PsAID12 questionnaire as a measure of HRQol in PsA. MCII and discrimination in clinical trials need to be defined. <h3>Reference</h3> 1. Boers M, Kirwan JR, Tugwell P, et al. The OMERACT Handbook. Accessed 5 January 2018, https://www.omeract.org/resources <h3>Disclosure of Interest:</h3> None declared