Are Changes in Physical Activity, Pain, and Quality of Life in Patients with Knee Osteoarthritis After Exercise Therapy and Education Beyond Normal Fluctuations? A Comparative Study

Objective: This study evaluates whether one-year changes in physical activity (PA), pain intensity, and quality of life (QOL) after exercise therapy and education are larger than normal fluctuations over time in individuals with knee osteoarthritis. Method: Patients with knee osteoarthritis participating in the Good Life with Osteoarthritis in Denmark (GLA:D®) exercise therapy and education program (n = 7603) and participants from the Osteoarthritis Initiative (OAI) who received no specific treatment (n = 1156) were included. PA was measured using the UCLA PA scale (1–10) in the GLA:D® group and the PASE (0–531) in the OAI group. PASE scores were mapped to the UCLA distribution. Pain intensity was measured using a standardized visual analog scale (VAS, 0–100), and QOL was assessed via the KOOS QOL scale (0–100). Changes were categorized as increased, maintained, and decreased. To ensure comparability between GLA:D® and OAI participants, we used entropy balancing, considering the covariables age, gender, BMI, depression, employment status, and our outcome variables at baseline. Results: At one year, 41% of GLA:D® participants showed increased PA compared to 38% in the balanced OAI group (p = 0.015). Pain intensity decreased by ≥20 mm on the VAS in 39% of GLA:D® and 27% of OAI participants (p < 0.001). QOL improved by ≥ 10 mm on the KOOS scale in 48% of GLA:D® and 40% of OAI participants (p < 0.001). Additionally, for PA, pain, and QOL, 6%, 13%, and 7% more patients in the control group experienced worsening in these outcomes, respectively. Conclusions: Twelve percent more participants experienced clinically relevant pain reductions in the GLA:D® group compared to OAI participants, and 3% and 8% more reported improvements in PA and QOL, respectively. Additionally, more patients in the control group experienced worsening in these outcomes. These differences indicate that clinically relevant pain improvements following exercise therapy and education may exceed normal fluctuations in patients with knee osteoarthritis.