Pain trajectory groups in persons with, or at high risk of, knee osteoarthritis: findings from the Knee Clinical Assessment Study and the Osteoarthritis Initiative.
Bottom Line: 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.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.
Affiliation: Arthritis Research UK Primary Care Centre, Research Institute for Primary Care and Health Sciences, Keele University, Keele, Staffordshire ST5 5BG, United Kingdom. Electronic address: firstname.lastname@example.org.Show MeSH
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Mentions: A linear 1-class latent class growth model showed an average increase in WOMAC Pain score of 0.08 points per year over the 6-year period (95% confidence interval: 0.02, 0.14). A 4-class linear model improved model fit, but with classes differentiated only by baseline score and not by slope (intercepts 2.4, 6.0, 10.4 and 15.3 respectively). The 5-class linear model produced interpretable trajectories and goodness-of-fit statistics that were not greatly inferior to the 4-class model, and was considered optimal (Table I). The trajectory groups were labelled on the basis of their intercepts and slopes as: “Mild, non-progressive” (N = 201, 35%), “Progressive” (N = 162, 28%), “Moderate” (N = 124, 22%) “Improving” (N = 68, 12%), “Severe, non-improving” (N = 15, 3%) (Fig. 1).
Affiliation: Arthritis Research UK Primary Care Centre, Research Institute for Primary Care and Health Sciences, Keele University, Keele, Staffordshire ST5 5BG, United Kingdom. Electronic address: email@example.com.