Nicholls E, Thomas E, van der Windt DA, Croft PR, Peat G. 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 Cartilage 2014;
22:2041-50. [PMID:
25305072 PMCID:
PMC4256061 DOI:
10.1016/j.joca.2014.09.026]
[Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 09/18/2014] [Accepted: 09/21/2014] [Indexed: 02/02/2023]
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.
Collapse