Direct-to-Participant Enrollment in a Virtual Trial

Background: Decentralized clinical trials using direct-to-participant recruitment can potentially engage large, representative participant pools.ObjectivesThe objective of the study was to share insights on multichannel strategies for participant recruitment in the decentralized Heartline Study, a randomized trial testing the impact of a mobile application-based heart health program with the electrocardiogram and Irregular Rhythm Notification features on an Apple Watch for early diagnosis, treatment, and outcomes of atrial fibrillation.MethodsEligible participants were U.S. 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 throughout the study to maximize reach.ResultsAcross multiple channels, 321,272 Heartline Study applications were installed, with 34,244 participants (11%) completing enrollment (February 2020-December 2022) and 82% (28,155/34,244) completing baseline demographic assessments. Women accounted for 54.2% (15,258/28,155) of study participants; 93.0% identified as White (26,192/28,155), 2.8% Asian (781/28,155), 2.7% Black (747/28,155), and 2.5% Hispanic (699/28,155). Broad geographic representation throughout the United States was achieved.ConclusionsThe Heartline Study demonstrated the ability to recruit large numbers of participants aged ≥65 years. A direct-to-participant approach across multiple channels achieved excellent gender and geographic diversity, enrolling a higher percentage of women than typical cardiology trials and participation from rural areas. However, less racial and ethnic representation was achieved, highlighting the need for additional strategies to meet this goal. Future trials may consider such multichannel recruitment approaches to support decentralized clinical trials.