"Insights for Direct-to-Patient Clinical Trial Recruitment Strategies From the Heartline Study"

Background: Decentralized clinical trials using direct-to-participant recruitment can potentially engage large, representative participant pools. Research Question: Can a decentralized clinical trial use a multichannel approach to recruit patients >65 years old across the United States? Goals/Aims: To share insights on multichannel strategies for participant recruitment in the decentralized, app-based Heartline study. Methods: Heartline is a randomized trial testing the impact of a mobile app-based heart health program with the electrocardiogram (ECG) and Irregular Rhythm Notification (IRN) features on Apple Watch for early diagnosis, treatment, and outcomes of atrial fibrillation. Eligible participants were US adults aged ≥65 years with an iPhone and Medicare coverage. Multiple pathways for broad outreach were explored, including digital (eg, email, social media) and traditional channels (eg, direct mail, community outreach). Recruitment efforts were assessed and refined to reach a large eligible population. Results: A multichannel approach led to ~300,000 Heartline study app installations. In total, 34,244 participants completed enrollment (Feb 2020-Dec 2022), of whom 28,155 completed baseline demographic assessments. Participants were widely distributed geographically, with notable representation of outlying and rural areas (Figure 1). Women accounted for 54% of the participants. Overall, most participants were White (93.0%), with Asian, Black, and Hispanic participants representing 2.8%, 2.7%, and 2.5%, respectively. Conclusion: The Heartline study demonstrated the ability to recruit large numbers of participants aged ≥65 years using a direct-to-participant approach. Broad outreach strategies ensured gender and geographic diversity, enrolling a higher percentage of women than typical cardiology trials, and participation from rural areas. However, underrepresentation across racial/ethnic groups persisted and strategies to increase enrollment are needed. For similar trials, a strategic multichannel approach, with strong data and analytics capabilities may be beneficial to effectively target and enroll eligible participants.