Qualitative Development of a Discrete Choice Experiment for Physical Activity Interventions to Improve Knee Osteoarthritis

Objective To describe the qualitative process used to develop attributes and attribute levels for inclusion in a discrete choice experiments (DCE) for older adult physical activity interventions. Design Five focus groups (n=41) were conducted, grounded in the Health Action Process Approach framework. Discussion emphasized identification and prioritization attributes for a DCE on physical activity. Semi-structured interviews (n=6) investigated attribute levels and lay-language for the DCE. A focus group with physical activity researchers and health care providers was the final stakeholder group used to establish a comprehensive approach for the generation of attributes and levels. A DCE pilot test (n=8) was then conducted with individuals of the target patient population. All transcripts were analyzed using a constant comparative approach. Setting General community and university-based research setting. Participants Volunteers (N=55) aged >45 years with knee pain, aches, or stiffness for at least 1 month over the previous 12 months. Interventions Not applicable. Main Outcome Measures Interview guides, attributes, attribute levels, and discrete choice experiment. Results The most influential identified attributes for physical activity were time, effort, cost, convenience, enjoyment, and health benefits. Each attribute had 3 levels that were understandable in the pilot test of the DCE. Conclusions The identification of 6 physical activity attributes that are most salient to adults with knee osteoarthritis resulted from a systematic qualitative process, including attribute-ranking exercises. A DCE will provide insight into the relative importance of these attributes for participating in physical activity, which can guide intervention development.