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Test-retest reliability for HAQ-DI and SF-36 PF for the measurement of physical function in psoriatic arthritis


J Rheumatol. 2021 Apr 15;jrheum.210175. doi: 10.3899/jrheum.210175. Online ahead of print.

Ying Ying Leung 1William Tillett 1Pil Hojgaard 1Ana-Maria Orbai 1Richard Holland 1Ashish J Mathew 1Niti Goel 1Jeffrey Chau 1Chris Lindsay 1Alexis Ogdie 1Laura C Coates 1Robin Christensen 1Philip Mease 1Vibeke Strand 1Dafna D Gladman 1

Author Information

1 Singapore General Hospital, Duke-NUS Medical School, Singapore; Duke-NUS Medical School, Singapore; Royal National Hospital for Rheumatic Diseases, University of Bath, Bath, United Kingdom; Department of Rheumatology, Holbaek Hospital, Danmark; Section for Biostatistics and Evidence-Based Research, the Parker Institute, Bispebjerg and Frederiksberg Hospital, Copenhagen; Division of Rheumatology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; Concord Repatriation General Hospital, Sydney, Australia; The Copenhagen Center for Arthritis Research, Centre for Rheumatology and Spine Disorders, Rigshospitalet Glostrup, University of Copenhagen, Denmark; Centre for Prognosis Studies in Rheumatic Diseases, Division of Rheumatology, Department of Medicine, University of Toronto, Toronto, Ontario Canada; Department of Clinical Immunology & Rheumatology, Christian Medical College, Vellore, India; Patient Research Partner, Adjunct Assistant Professor, Duke University School of Medicine, Durham, North Carolina, USA; Patient Research Partner, Hong Kong; Patient Research Partner, Employed by Aurinia Pharma US Inc., Prosper, Texas USA; Medicine and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; National Institute for Health Research Clinician Scientist, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom; Research Unit of Rheumatology, Department of Clinical Research, University of Southern Denmark, Odense University Hospital, Denmark; Rheumatology Research, Swedish Medical Center and University of Washington School of Medicine, Seattle, Washington, USA; Division of Immunology/Rheumatology, Stanford University School of Medicine, Palo Alto, California, USA; Medicine, University of Toronto, Senior Scientist, Krembil Research Institute, Director, Psoriatic Arthritis Program, University Health Network, Toronto Western Hospital, Toronto, Ontario, Canada. Correspondence to: Ying-Ying Leung, MD; Department of Rheumatology and Immunology, Singapore General Hospital, The Academia, level 4, 20 College Road, Singapore 169856. E-mail: katyccc@hotmail.com.


Objective: Due to no existing data, we aimed to derive evidence to support test-retest reliability for the Health Assessment Questionnaire-Disability Index (HAQ-DI) and Medical Outcome Survey Short-Form-36 item physical functioning domain (SF-36 PF) in psoriatic arthritis (PsA).

Methods: We identified datasets that collected relevant data for test-retest reliability for HAQ-DI and SF-36 PF; and evaluated them using OMERACT Filter 2.1 methodology. We calculated intra-class correlation coefficients (ICC) as a measure of test-retest reliability. We then conducted a quality assessment and evaluated the adequacy of test-retest reliability performance.

Results: Two datasets were identified for HAQ-DI and one for SF-36 PF in PsA. The quality of the datasets was good. The ICCs for HAQ-DI were excellent in both datasets: 0.94 (95% CI: 0.88 to 0.97) and 0.94 (95% CI: 0.89 to 0.97). The ICC of SF-36 PF was good (0.89, 95% CI: 0.76 to 0.95). The performance of test-retest reliability for both instruments was judged to be adequate.

Conclusion: The new data derived support good and reasonable test-retest reliability for HAQ-DI and SF-36 PF in PsA.