THU0712-HPR Trajectories of pain and physical function in patients with symptomatic knee and hip osteoarthritis: results from the french population-based khoala cohort
Authors: M. Wieczorek, C. Rotonda, F. Guillemin, A.-C. Rat
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Objectives</h3> The aims of this study were to identify homogeneous subgroups with distinct trajectories of pain and physical function in patients with symptomatic knee and/or hip OA and to identify the baseline predictive factors associated with these trajectories. <h3>Methods</h3> The KHOALA cohort is a French population-based multi-center cohort of 878 patients with symptomatic knee and/or hip OA, aged between 40 and 75 years old. Pain and function were measured annually with the WOMAC questionnaire. Baseline comorbidities were assessed by the Functional Comorbidity Index (FCI), perceived vitality was measured with SF-36 and psychosocial distress with the General Health Questionnaire (GHQ). Using the follow-up data over 5 years, latent class growth analyses (LCGA) were used to identify homogeneous subgroups with distinct trajectories of pain and function. The selection of the optimal models was based on maximisation of the Bayesian information criterion, the proportion of patients in each trajectory group (&gt;5%) and the statistical significance of the equation modelled (intercept only, linear, quadratic or cubic). Multinomial logistic regressions were performed to identify the predictive baseline characteristics associated with each trajectory and were adjusted for socio demographic and clinical factors. <h3>Results</h3> Among the 878 patients, 609 (69.4%) were women, 222 (25.3%) had hip OA, 607 (69.1%) knee OA and 49 (5.6%) both hip and knee OA. LCGA revealed 4 distinct linear and stable trajectories of pain: "no pain" (n=131, 16.2%), "mild pain" (n=269, 33.3%), "moderate pain" (n=247, 30.5%), and "severe pain" (n=162, 20.0%). Compared with the "no pain" group, subjects belonging to the subgroup "severe pain" were more likely to be female (Odds ratio [OR]=5.13, 95% confidence interval [CI]=2.46–10.70), with a high body mass index (BMI) (OR=1.13, 95%CI=1.07–1.20), a high number of comorbidities (OR=1.42, 95%CI=1.13–1.78), a low vitality score (thus a high level of fatigue; OR=0.94, 95%CI=0.91–0.96), a high disease duration (OR=1.06, 95%CI=1.02–1.10), and a low GHQ score (thus a high psychosocial distress; OR=0.94, 95%CI=0.91–0.98). For physical function, 4 distinct stable trajectories were identified: "no functional limitations" (n=239, 29.6%), "low functional limitations" (n=266, 32.9%), "moderate functional limitations" (n=208, 25.7%), "severe functional limitations" (n=95, 11.8%). In multivariate analyses, female sex (OR=5.11, 95%CI=2.04–12.81), increasing age (OR=1.13, 95% CI: 1.08–1.18), a high BMI (OR=1.15, 95%CI=1.08–1.21), a high number of comorbidities (OR=1.28, 95%CI=1.12–1.61), a low vitality score (thus a high level of fatigue; OR=0.91, 95%CI=0.88–0.93), and a low GHQ score (thus a high psychological distress; OR=0.96, 95%CI=0.93–0.99) were associated with the trajectory of "severe functional limitations". <h3>Conclusions</h3> Based on the 5 year follow-up data, we identified 4 distinct trajectories of pain and 4 trajectories of physical function. None of the trajectories demonstrated worsening or improvement over time, confirming that OA is a chronic persistent disease that does not inevitably worsen. <h3>Disclosure of Interest</h3> None declared