Determinants of pain and functioning in hip osteoarthritis - a two-year prospective study

Objective: To identify predictors of pain and disability in hip osteoarthritis. Design: A prospective analysis of determinants of pain and functioning in hip osteoarthritis. Study setting: Rehabilitation clinic in a central hospital. Patients: A total of 118 men and women aged 55-80 years who had radiologically diagnosed hip osteoarthritis and associated clinical symptoms and participated in a randomized controlled trial. Main measures: The self-reported disease-specific pain and physical function were assessed using the pain and functioning subscales of the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis index. The self-reported generic physical and mental functioning were assessed by using the Finnish-validated SF-36-item Health Survey RAND-36 subscales for function and physical and mental component summary scores. Outcome measures were recorded at 0, 3, 6, 12, 18 and 24 months. Results: Multivariate linear mixed model analyses revealed that lower disease-specific pain score and better functioning (WOMAC) were predicted by higher educational level (9.61 (3.15 to 16.07); 9.07 (2.05 to 16.09)), supervised exercise training (-10.13 (-17.87 to -2.39); -11.58 (-19.40 to -3.77)), habitual conditioning physical activity (-0.48 (-0.96 to -0.01); -0.39 (-0.84 to 0.05)), absence of comorbidities (-6.30 (-12.35 to -0.24); -7.87 (-14.45 to -1.30)) and absence of additional knee osteoarthritis (-7.62 (-13.87 to -1.36); -8.02 (-14.81 to -1.23)), respectively. The same factors, except for the comorbidities, also predicted general physical functioning score (RAND-36). Conclusions: Higher education, absence of knee osteoarthritis and comorbidities, supervised exercise training and habitual conditioning physical activity predicted a lower presence of pain and better functional status in patients with hip osteoarthritis.