A systematic review of measurement properties of patient reported outcome measures in psoriatic arthritis: A GRAPPA-OMERACT initiative

Background: An updated psoriatic arthritis (PsA) core outcome set (COS) for randomized controlled trials (RCTs) was endorsed at the Outcome Measures in Rheumatology (OMERACT) meeting in 2016. Objectives: To synthesize the evidence on measurement properties of patient reported outcome measures (PROMs) for PsA and thereby contribute to development of a PsA core outcome measurement set (COMS) as described by the OMERACT Filter 2.0. Methods: A systematic literature search was performed in EMBASE, MEDLINE and PsycINFO on Jan 1, 2017 to identify full-text articles with an aim of assessing the measurement properties of PROMs in PsA. Two independent reviewers rated the quality of studies using the COnsensus based standards for the Selection of health Measurement INstruments (COSMIN) checklist, and performed a qualitative evidence synthesis. Results: Fifty-five studies were included in the systematic review. Forty-four instruments and a total of 89 scales were analyzed. PROMs measuring COS domains with at least fair quality evidence for good validity and reliability (and no evidence for poor properties) included the Stockerau Activity Score for PsA (German), Psoriasis Symptom Inventory, visual analogue scale for Patient Global, 36 Item Short Form Health Survey Physical Function subscale, Health Assessment Questionnaire Disability Index, Bath Ankylosing Spondylitis Functional Index, PsA Impact of Disease questionnaire, PsA Quality of Life questionnaire, VITACORA-19, Functional Assessment of Chronic Illness Therapy Fatigue scale and Social Role Participation Questionnaire. Conclusions: At least one PROM with some evidence for aspects of validity and reliability was available for six of the eight mandatory domains of the PsA COS.