Abstract
Objective: This study aimed to investigate potential moderators influencing the effects of manual therapy and exercise therapy on pain and functional outcomes in individuals with knee and/or hip osteoarthritis, using data from the MOA trial.
Design: This is a secondary analysis of data from the MOA trial that compared the clinical effectiveness of manual therapy and/or exercise therapy in addition to usual care for patients with hip and/or knee osteoarthritis.
Methods: 206 participants were analysed. The primary outcome measure was the WOMAC composite score after 1 year. The secondary outcome measures were WOMAC pain and function scores. We used linear regression models for assessing whether the effect of randomized interventions on pain and function was moderated by body mass index (BMI), pain self-efficacy, quadriceps strength, mental health, education.
Results: BMI moderated the treatment effect of manual therapy interventions on WOMAC composite score (β:-4.1, 95%CI: -6.6, -1.7), WOMAC function score (β:-3.3, 95%CI = -5.1, -1.6) and WOMAC pain scores (β:-0.6, 95%CI: -1.3, 0.0), when compared to usual care. Negative β reflects an improvement in outcome associated with each one unit increase in BMI. Mental health moderated (β:16.8, 95%CI: 2.2, 31.4) of manual therapy interventions when compared to usual care. No other moderation effect was identified.
Conclusions: Our findings suggest manual therapy may prove to be a more suitable treatment for people with higher BMI and should undergo further trials. Future trials should continue to explore which variables moderate treatment effects when testing effectiveness of non-surgical interventions in patients with hip or knee osteoarthritis.