"From Where I Stand": using multiple anchors yields different benchmarks for meaningful improvement and worsening in the rheumatoid arthritis flare questionnaire (RA-FQ)

Abstract

Purpose: The Rheumatoid Arthritis Flare Questionnaire (RA-FQ) is a patient-reported measure of disease activity in RA. We estimated minimal and meaningful change from the perspective of RA patients, physicians, and using a disease activity index.

Methods: Data were from 3- to 6-month visits of adults with early RA enrolled in the Canadian Early Arthritis Cohort. Participants completed the RA-FQ, the Patient Global Assessment of RA, and the Patient Global Change Impression at consecutive visits. Rheumatologists recorded joint counts and MD Global. Clinical Disease Activity Index (CDAI) scores were computed. We compared mean RA-FQ change across categories using patients, physicians, and CDAI anchors.

Results: The 808 adults were mostly white (84%) women (71%) with a mean age of 55 and moderate-high disease activity (85%) at enrollment. At V2, 79% of patients classified their RA as changed; 59% were better and 20% were worse. Patients reporting they were a lot worse had a mean RA-FQ increase of 8.9 points, whereas those who were a lot better had a -6.0 decrease. Minimal worsening and improvement were associated with a mean 4.7 and - 1.8 change in RA-FQ, respectively, while patients rating their RA unchanged had stable scores. Physician and CDAI classified more patients as worse than patients, and minimal and meaningful RA-FQ thresholds differed by group.

Conclusion: Thresholds to identify meaningful change vary by anchor used. These data offer new evidence demonstrating robust psychometric properties of the RA-FQ and offer guidance about improvement or worsening, supporting its use in RA care, research, and decision-making.

Keywords: Flare; Minimally important differences; Patient-reported outcomes; Rheumatoid arthritis.