Objective: To present and vote on a myositis modified patient-reported outcome core domain set in the life impact area at the Outcome Measures in Rheumatology (OMERACT) 2018.
Methods: Based on results from international focus groups and Delphi surveys, a draft core set was developed.
Results: Domains muscle symptoms, fatigue, level of physical activity, and pain reached ≥ 70% consensus and were mandatory to assess in all trials. Domains lung, joint, and skin symptoms were mandatory in specific circumstances. This core set was endorsed by > 85% at OMERACT 2018.
Conclusion: We propose a life impact core set for patients with idiopathic inflammatory myopathies and will proceed with instrument selections.
Keywords: DELPHI; MYOSITIS; OMERACT; OUTCOME ASSESSMENT; PATIENT-REPORTED OUTCOMES.