Telephone Coaching to Enhance a Home‐Based Physical Activity Program for Knee Osteoarthritis: A Randomized Clinical Trial

Objective To investigate whether simultaneous telephone coaching improves the clinical effectiveness of a physiotherapist‐prescribed home‐based physical activity program for knee osteoarthritis (OA). Methods A total of 168 inactive adults ages ≥50 years with knee pain on a numeric rating scale ≥4 (NRS; range 0–10) and knee OA were recruited from the community and randomly assigned to a physiotherapy (PT) and coaching group (n = 84) or PT‐only (n = 84) group. All participants received five 30‐minute consultations with a physiotherapist over 6 months for education, home exercise, and physical activity advice. PT+coaching participants also received 6–12 telephone coaching sessions by clinicians trained in behavioral‐change support for exercise and physical activity. Primary outcomes were pain (NRS) and physical function (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC; score range 0–68]) at 6 months. Secondary outcomes were these same measures at 12 and 18 months, as well as physical activity, exercise adherence, other pain and function measures, and quality of life. Analyses were intent‐to‐treat with multiple imputation for missing data. Results A total of 142 (85%), 136 (81%), and 128 (76%) participants completed 6‐, 12‐, and 18‐month measurements, respectively. The change in NRS pain (mean difference 0.4 unit [95% confidence interval (95% CI) −0.4, 1.3]) and in WOMAC function (1.8 [95% CI −1.9, 5.5]) did not differ between groups at 6 months, with both groups showing clinically relevant improvements. Some secondary outcomes related to physical activity and exercise behavior favored PT+coaching at 6 months but generally not at 12 or 18 months. There were no between‐group differences in most other outcomes. Conclusion The addition of simultaneous telephone coaching did not augment the pain and function benefits of a physiotherapist‐prescribed home‐based physical activity program.