"I feel more confident": a mixed methods evaluation of the influence of Good Life with osteoarthritis Denmark (GLA:D®) on physical activity participation, capability, barriers, and facilitators in people with knee osteoarthritis.

Background: A mixed methods study which aimed to evaluate the influence of Good Life with osteoArthritis Denmark (GLA:D®) on physical activity participation, including perceived capability, barriers, and facilitators in people with knee osteoarthritis.

Objective: Quantify changes in physical activity participation at 3- and 12-months for people with knee osteoarthritis who participated in an education and exercise-therapy program (GLA:D®).

Methods: A mixed-methods study involving 44 participants with knee osteoarthritis who completed GLA:D®. Guided by the Theoretical Domains Framework, 19 were interviewed, with transcripts analysed using reflexive thematic analysis. University of California Los Angeles physical activity scores were dichotomised as 'more' (≥7) or 'less' active (≤6), and compared between baseline and 3- and 12-months using McNemar's test. Motivation and confidence to exercise (0-10 scale); fear of knee joint damage with exercise (yes/no); and Knee Osteoarthritis Outcome Scores (KOOS) were evaluated.

Results: Four overarching themes were identified: prior to GLA:D® 1) fear of knee joint damage, and scarcity of exercise and physical activity information prior to GLA:D®; and following GLA:D® 2) varied exercise-therapy and physical activity participation; 3) facilitators including reduced fear of knee damage, increased confidence, routine, strategies, and support; and 4) ongoing barriers including persistent knee pain, comorbidities, cost, and lack of opportunity and motivation. There was no difference in the proportion of 'more' active participants between baseline (41%) and at 3-months (37%, p = 0.774) or 12-months (35%, p = 0.375). The proportion with fear of damage reduced from baseline (50%) to 3-months (5%) and 12-months (21%). Self-reported motivation (9.1/10) and confidence (9.1/10) to exercise at 3-months were high, and all KOOS subscales improved from baseline to 3-months (effect sizes = 0.41-0.58) and 12-months (effect sizes = 0.29-0.66).

Conclusion: Varied and often inadequate physical activity participation following GLA:D® indicates more targeted interventions to address ongoing barriers may be required.