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Notable Publication: OMERACT Myositis Working Group Explores Responsiveness and Meaningful Thresholds of PROMIS Forms in Patients with Idiopathic Inflammatory Myopathies

March 22, 2024

The OMERACT Myositis Working Group recently published a notable report in Seminars in Arthritis and Rheumatism that assessed responsiveness of PROMIS instruments in evaluation of patients with idiopathic inflammatory myositis (IIM).

Didem Saygin, MD, assistant professor of Medicine in the UPMC Division of Rheumatology and Clinical Immunology, and the OMERACT Myositis Working Group ultimately found value in PROMIS physical function, fatigue, and pain interference forms in an international cohort of patients with IIM.

Background: Qualitative studies conducted by the OMERACT Myositis Working Group identified pain interference, fatigue, and physical function as highly important life impact domains for adults with IIM. The goal of this study was to assess the responsiveness and minimal important difference of PROMIS pain interference, fatigue, and physical function.

Methods: Adults with IIM from the United States, Netherlands, Korea, Sweden, and Australia with two clinical visits were enrolled in this prospective study. Anchor questions on a Likert scale were collected at baseline, and manual muscle testing (MMT), physician and patient reported global disease activity, and PROMIS instruments were collected at both visits. Responsiveness was assessed with: ANOVA; paired t-test; effect size and standardized response mean; and Pearson correlation. 

Minimal important difference (MID), minimal important change (MIC), and minimal detectable change (MDC) values were calculated.

Results: 114 patients with IIM completed both visits. Changes in PROMIS instruments greatly differed among anchor categories. Patients who reported improvement had a significant increase in their PROMIS scores with at least medium effect size, while patients who reported either worsening or stability did not show a significant change with weak effect size. 

PROMIS instruments had weak to moderate correlations with MMT and patient and physician global disease activity. MID was approximately 2–3 points for Pain Interference and 3–4 points for Fatigue and Physical Function forms based on the method used. MIC was approximately 4–5 for improvement of all the instruments, while MDC was 1.7–2 points for Pain Interference and Physical Function and 3.2–3.9 for Fatigue.

Conclusion: This study demonstrates the responsiveness of the PROMIS instruments in a large international prospective cohort of adults with IIM supporting their use as PROMs in adult myositis.


D Saygin, D DiRenzo, J Raaphorst, I de Groot, CO Bingham, IE Lundberg, M Regardt, C Sarver, M de Visser, LJ Maxwell, D Beaton, JY Kim, M Needham, H Alexanderson, L Christopher-Stine, CA Mecoli, JK Park. Responsiveness and meaningful thresholds of PROMIS pain interference, fatigue, and physical function forms in adults with idiopathic inflammatory myopathies: Report from the OMERACT Myositis Working Group. Seminars in Arthritis and Rheumatism, Volume 64, 2024, 152339, ISSN 0049-0172,