Canadian adaptive platform trial of treatments for COVID in community settings (CanTreatCOVID): recruitment strategies of a decentralized, national randomized controlled trial for acute SARS-CoV-2

Background Recruitment remains a challenge in clinical trials. This study describes the use of digital and traditional recruitment channels in a national, community-based adaptive platform trial for COVID-19 in Canada. Methods Self-reported recruitment sources were collected from participants of a remote, national adaptive platform trial of COVID-19 treatments conducted across six Canadian provinces using a secure web-based application. Recruitment channels were analyzed using descriptive statistics, chi-square tests, and logistic regression to explore associations with province. Results From January 2023 to September 2024, 1,515 participants completed the pre-screening process, and 720 were randomized. Of them, 416 were recruited through traditional channels, 303 through digital channels, and one through an undetermined source. Recruitment channels varied by province ( χ 2 (5) = 81.30, p < 0.001; Cramér’s V = 0.34), and digital channels were associated with higher odds of recruitment compared with traditional channels (adjusted OR = 2.78, 95% CI 2.20–3.52). The most frequently reported referral source was ‘family, friends, or colleagues’ (20%), followed by provincial government websites and health lines (16.25%), online channels (10.56%), and public communications (9.86%). Conclusion Combining traditional and digital recruitment methods supports recruitment. Trials can raise awareness of the study by leveraging both digital and traditional channels and can move information to action through trusted social groups and institutions. Further research is needed to evaluate the cost-effectiveness, reach, and demographic differences across platforms, informing recruitment strategies in future decentralized and adaptive trials beyond COVID-19. Clinical trial registration https://clinicaltrials.gov/study/NCT05614349 , Identifier NCT05614349.