Pain trajectory groups in persons with, or at high risk of, knee osteoarthritis: findings from the Knee Clinical Assessment Study and the Osteoarthritis Initiative

Nicholls, E; Thomas, E; van der Windt, DA; Croft, PR; Peat, G

Abstract

OBJECTIVE: The authors aimed to characterize distinct trajectories of knee pain in adults who had, or were at high risk of, knee osteoarthritis using data from two population-based cohorts. METHOD: Latent class growth analysis was applied to measures of knee pain severity on activity obtained at 18-month intervals for up to 6 years between 2002 and 2009 from symptomatic participants aged over 50 years in the Knee Clinical Assessment Study (CAS-K) in the United Kingdom. The optimum latent class growth model from CAS-K was then tested for reproducibility in a matched sample of participants from the Osteoarthritis Initiative (OAI) in the United States. RESULTS: A 5-class linear model produced interpretable trajectories in CAS-K with reasonable goodness of fit and which were labelled "Mild, non-progressive" (N = 201, 35%), "Progressive" (N = 162, 28%), "Moderate" (N = 124, 22%) "Improving" (N = 68, 12%), and "Severe, non-improving" (N = 15, 3%). We were able to reproduce "Mild, non-progressive", "Moderate", and "Severe, non-improving" classes in the matched sample of participants from the OAI, however, absence of a "Progressive" class and instability of the "Improving" classes in the OAI was observed. CONCLUSIONS: Our findings strengthen the grounds for moving beyond a simple stereotype of osteoarthritis as "slowly progressive". Mild, non-progressive or improving symptom trajectories, although difficult to reproduce, can nevertheless represent a genuinely favourable prognosis for a sizeable minority.

Citation

Nicholls, E., Thomas, E., van der Windt, D., Croft, P., & Peat, G. (2014). Pain trajectory groups in persons with, or at high risk of, knee osteoarthritis: findings from the Knee Clinical Assessment Study and the Osteoarthritis Initiative. Osteoarthritis and Cartilage, 22(12), 2041 - 2050. https://doi.org/10.1016/j.joca.2014.09.026

• Journal Article Type: Article
• Acceptance Date: Sep 21, 2014
• Online Publication Date: Oct 8, 2014
• Publication Date: 2014-12
• Journal: Osteoarthritis and Cartilage
• Print ISSN: 1063-4584
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 22
• Issue: 12
• Pages: 2041 - 2050
• DOI: https://doi.org/10.1016/j.joca.2014.09.026
• Keywords: knee, latent class growth analysis, osteoarthritis, pain
• Publisher URL: http://www.sciencedirect.com/science/article/pii/S1063458414012783