Recruiting and Consenting Decentralized Clinical Trial Participants-Learnings from the Trials@Home RADIAL Proof-of-Concept Trial

Clinical trials often face recruitment challenges. From the participant's perspective, barriers such as time commitment, travel to sites, and logistical burden, like arranging care duties or time off work, can deter enrolment. Decentralized clinical trials (DCTs) aim to address these by shifting activities closer to participants' homes and using online methods for recruitment and consent. This study explores recruitment strategies and remote eConsent implementation in a decentralized setting. The RADIAL trial, a three-arm, open-label, phase IV study in six European countries, enrolled participants with type 2 diabetes mellitus administering Insulin Glargine 300 U/ml. Recruitment strategies included online campaigns, search engine advertising, social media, and research database outreach. The remote consent process involved eConsent, telemedicine consultations, eIdentification, and eSignatures. Online recruitment campaigns generated a lot of impressions but led to very few pre-screener completions or enrolments. In contrast, outreach through research databases proved more effective, accounting for 7 of the 8 enrolled participants in the decentralized arm. Major pre-screening drop-off occurred at the initial consent step, with 69% exiting before data collection. Eleven participants successfully completed eConsent; 4 others required remote paper-based consent due to eIdentification issues. Implementing the multimedia-enhanced eConsent system was resource-intensive, complicated by country-specific layouts and differing regulatory requirements. Tailored recruitment strategies and simplified remote consent processes are needed to enhance the accessibility and efficiency of DCTs. Further research should optimize targeting and keyword use in online recruitment.