Background The objective was to compare different definitions of remission and low disease activity (LDA) in patients with psoriatic arthritis (PsA), based on both patients’ and physicians’ perspectives.
Methods In ReFlap (Remission/Flare in PsA; NCT03119805), adults with physician-confirmed PsA and >2 years of disease duration in 14 countries were included. Remission was defined as very low disease activity (VLDA), Disease Activity index for PSoriatic Arthritis (DAPSA) ≤4, and physician-perceived and patient-perceived remission (specific question yes/no), and LDA as minimal disease activity (MDA), DAPSA <14, and physician-perceived and patient-perceived LDA. Frequencies of these definitions, their agreement (prevalence-adjusted kappa), and sensitivity and specificity versus patient-defined status were assessed cross-sectionally.
Results Of 410 patients, the mean age (SD) was 53.9 (12.5) years, 50.7% were male, disease duration was 11.2 (8.2) years, 56.8% were on biologics, and remission/LDA was frequently attained: respectively, for remission from 12.4% (VLDA) to 36.1% (physician-perceived remission), and for LDA from 25.4% (MDA) to 43.9% (patient-perceived LDA). Thus, patient-perceived remission/LDA was frequent (65.4%). Agreement between patient-perceived remission/LDA and composite scores was moderate to good (kappa range, 0.12–0.65). When patient-perceived remission or LDA status is used as reference, DAPSA-defined remission/LDA and VLDA/MDA had a sensitivity of 73.1% and 51.5%, respectively, and a specificity of 76.8% and 88.0%, respectively. Physician-perceived remission/LDA using a single question was frequent (67.6%) but performed poorly against other definitions.
Conclusion In this unselected population, remission/LDA was frequently attained. VLDA/MDA was a more stringent definition than DAPSA-based remission/LDA. DAPSA-based remission/LDA performed better than VLDA/MDA to detect patient-defined remission or remission/LDA. Further studies of long-term outcomes are needed.
- psoriatic arthritis
- patient perspective
- disease activity
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Handling editor David S Pisetsky
Contributors All authors except MdW were responsible for acquisition of data. CG, DP-Z, A-MO, LCC, JSS, MdW and LG contributed to study conception and design and data analysis. All authors contributed to data interpretation. CG and LG take responsibility for the integrity of the data and the accuracy of the data analysis. All authors were involved in drafting the article or revising it critically for important intellectual content, and approved the final version to be submitted for publication.
Funding The study received financial support from Pfizer through an unrestricted research grant. The fellow CG was additionally supported by a master’s bursary from Societe Francaise de Rhumatologie. LCC is funded by a National Institute for Health Research Clinician Scientist Award. Her research was supported by the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC). A-MO is a Jerome L Greene Foundation Scholar and is supported in part by a research grant from the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) of the National Institutes of Health (NIH) under award number P30-AR070254 (Core B), a Rheumatology Research Foundation Scientist Development Award, and a Staurulakis Family Discovery Award.
Disclaimer All the statements in this report including its conclusions are the opinions of the authors and do not necessarily reflect those of NIH or NIAMS or the Foundation. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health.
Competing interests None declared.
Patient consent Obtained.
Ethics approval Ethics approval was sought and obtained in each country or centre
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement The dataset of ReFlap study is available upon request from LG.
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