This article was prepared using an OAI public use data set and does not necessarily reflect the opinions or views of the OAI investigators, the NIH, or the private funding partners. This article presents independent research funded in part by the NIHR. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, or the Department of Health and Human Services.
Special Theme Articles: Mobility and the Rheumatic Diseases
Toward a Clinical Definition of Early Osteoarthritis: Onset of Patient-Reported Knee Pain Begins on Stairs. Data From the Osteoarthritis Initiative†
Article first published online: 27 DEC 2014
© 2015 The Authors. Arthritis Care & Research is published by Wiley Periodicals, Inc. on behalf of the American College of Rheumatology.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Arthritis Care & Research
Volume 67, Issue 1, pages 40–47, January 2015
How to Cite
Hensor, E. M. A., Dube, B., Kingsbury, S. R., Tennant, A. and Conaghan, P. G. (2015), Toward a Clinical Definition of Early Osteoarthritis: Onset of Patient-Reported Knee Pain Begins on Stairs. Data From the Osteoarthritis Initiative. Arthritis Care Res, 67: 40–47. doi: 10.1002/acr.22418
- Issue published online: 27 DEC 2014
- Article first published online: 27 DEC 2014
- Accepted manuscript online: 29 JUL 2014 11:00AM EST
- Manuscript Accepted: 22 JUL 2014
- Manuscript Received: 27 FEB 2014
- NIH. Grant Numbers: N01-AR-2-2258, N01-AR-2-2259, N01-AR-2-2260, N01-AR-2-2261, N01-AR-2-2262
- Department of Health and Human Services
- Osteoarthritis Initiative Investigators
- Merck Research Laboratories
- Novartis Pharmaceuticals Corporation
- Arthritis Research UK
- Wellcome Trust
- Engineering and Physical Sciences Research Council
Early detection of osteoarthritis (OA) would increase the chances of effective intervention. We aimed to investigate which patient-reported activity is first associated with knee pain. We hypothesized that pain would occur first during activities requiring weight bearing and knee bending.
Data were obtained from the Osteoarthritis Initiative (OAI), a multicenter, longitudinal prospective observational cohort of people who have or are at high risk of OA. Participants completed the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC; Likert scale) annually for up to 7 years. Rasch analysis was used to rank the WOMAC pain questions (activities) in order of affirmation as the pain score increased from 0. For each total WOMAC score category (0–20) we selected 25 individuals at random based on their maximum score across all visits. Fit to the Rasch model was assessed in this subset; stability of question ranking over successive visits was confirmed in the full OAI.
WOMAC data on 4,673 people were included, with 491 selected for subset analysis. The subset data showed good fit to the Rasch model (χ2 = 43.31, P = 0.332). In the full OAI, the “using stairs” question was the first to score points as the total pain score increased from 0 (baseline logit score ± 95% confidence interval −4.74 ± 0.07), then “walking” (−2.94 ± 0.07), “standing” (−2.65 ± 0.07), “lying/sitting” (−2.00 ± 0.08), and finally “in bed” (−1.32 ± 0.09). This ordering was consistent over successive visits.
Knee pain is most likely to first appear during weight-bearing activities involving bending of the knee, such as using stairs. First appearance of this symptom may identify a group suitable for early intervention strategies.