Thomas, MJ, Rathod-Mistry, T, Parry, EL, Pope, C, Neogi, T and Peat, G (2021) Triggers for acute flare in adults with, or at risk of, knee osteoarthritis: a web-based case-crossover study in community-dwelling adults. Osteoarthritis and Cartilage, 29 (7). pp. 956-964. ISSN 1522-9653

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OBJECTIVE: To identify proximate causes ('triggers') of flares in adults with, or at risk of, knee osteoarthritis (OA), estimate their course and consequences, and determine higher risk individuals. METHODS: In this 13-week web-based case-crossover study adults aged ≥40 years, with or without a recorded diagnosis of knee OA, and no inflammatory arthropathy who self-reported a knee flare completed a questionnaire capturing information on exposure to 21 putative activity-related, psychosocial and environmental triggers (hazard period, ≤72 hours prior). Comparisons were made with identical exposure measurements at four 4-weekly scheduled time points (non-flare control period) using conditional logistic regression. Flare was defined as a sudden onset of worsening signs and symptoms, sustained for ≥24 hours. Flare characteristics, course and consequence were analysed descriptively. Associations between flare frequency and baseline characteristics were estimated using Poisson regression. RESULTS: Of 744 recruited participants (mean age (SD) 62.1 (10.2) years; 61% female), 376 reported 568 flares (hazards) and provided 867 valid control period measurements. Thirteen exposures (8 activity-related, 5 psychosocial/environmental) were positively associated with flare onset within 24 hours (strongest odds ratio estimate, knee buckling: 9.06: 95% confidence interval [CI] 5.86, 13.99; weakest, cold/damp weather: 1.45: 95%CI 1.12, 1.87). Median flare duration was 5 days (IQR 3, 8), less common if older (incident rate ratio [IRR] 0.98: 95%CI 0.97, 0.99), more common if female (IRR 1.85: 95%CI 1.43, 2.39). CONCLUSIONS: Multiple activity-related, psychosocial and environmental exposures are implicated in triggering flares. This evidence can help inform prevention and acute symptom management for patients and clinicians.

Item Type: Article
Additional Information: © 2021 The Authors. Published by Elsevier Ltd on behalf of Osteoarthritis Research Society International. This is an open access article under the CC BY-NC-ND license (
Uncontrolled Keywords: Knee; Osteoarthritis; Flare; Web-based; Case-crossover
Subjects: R Medicine > RA Public aspects of medicine
R Medicine > RC Internal medicine > RC925 Diseases of the musculoskeletal system
R Medicine > RC Internal medicine > RC927 Rheumatism
Divisions: Faculty of Medicine and Health Sciences > School of Primary, Community and Social Care
Related URLs:
Depositing User: Symplectic
Date Deposited: 11 May 2021 13:29
Last Modified: 11 Aug 2021 10:32

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