A BCT Intervention for Physical Activity Among Individuals on Statins

The purpose of this project is to identify the minimum effective dose (MED) of a multi-component behavioral change intervention required to increase levels of physical activity (PA) among participants on primary prevention statin therapy who are at elevated risk for cardiovascular disease (CVD). The intervention will be comprised of 5 BCTs which have previously shown to be effective on increasing health behaviors: Goal Setting, Action Planning, Self-Monitoring, Feedback, and Prompts/Cues. Participants will complete a 2-week baseline run-in period where PA levels will be measured using Fitbit wearable device. Then 42 participants will be randomized into 14 cohorts of 3 participants each for the intervention period. During the intervention period, participants will receive a multi-BCT intervention, the length of which varies between 1 and 10 weeks depending on the assigned dose. Assignment to doses will utilize a modified version of the Time-to-Event Continual Reassessment Method (TiTE-CRM) methodology to adjust the dose for each cohort based on the results from the previous cohort. After the intervention, there will be a 2-week follow-up period. The MED will be defined as the smallest BCT dose (defined by weeks of intervention) associated with 80% of participants having a successful PA increase between the run-in and the follow-up periods (defined as walking an extra 2,000 more steps per day).