Diverse Recruitment for Clinical Trials Using Three Diversity-Enhancing Interventions: Qualitative Study

Abstract Background Lack of diversity in clinical trials reduces the generalizability of treatment efficacy across different demographic groups, thereby diminishing the relevance, quality, and equity of research findings. Objective This study aimed to evaluate the implementation of 4 recruitment strategies and their impact on clinical trial enrollment through the Trial of Sites to Increase Diversity in Clinical Trials (TOTAL) project, a collaboration between Stanford and Morehouse School of Medicine funded by the American Heart Association. Methods Clinical trials were randomized to 1 of 3 recruitment strategy intervention arms (community ambassador, social media ads, or registry and patient engagement platforms) or the control arm (usual recruitment). The Stanford Lightning Report, a rapid qualitative approach, was used to gather insights through interviews with principal investigators (PIs) and trial staff at baseline, 3 months, and trial completion. Results Trial teams were supportive of increasing diversity and found the recruitment platforms generally user-friendly. External recruitment support was valued, and some trials reported improved access to participants outside their usual pool. Community ambassadors helped connect trials with community and physician networks and, in some cases, increased recruitment of Asian American participants. Registry and patient engagement platforms were easy to use and supported outreach, including direct emails to potential participants. Social media ads, particularly after the transition to BuildClinical (BuildClinical LLC), improved screening efficiency by prescreening candidates and producing a manageable number of eligible leads. Usual recruitment relied mainly on physician referrals and benefited from trusted clinician-patient relationships, but many trials exhausted their typical participant pools. Across strategies, major barriers included limited time, staff capacity, and financial resources; scarcity of diverse local populations; restrictive eligibility criteria; lack of language access; transportation burdens; and limitations of remote engagement. Additional operational barriers included institutional review board (IRB) delays, contract and vendor approval processes, and platform policy restrictions for digital advertising. Feedback from Lightning Reports led to several real-time changes, including a shift from in-house social media outreach to specialized digital recruitment support. Conclusions Increasing diversity in clinical trials requires sustained financial, human, and institutional support, as well as effective recruitment strategies. Rapid qualitative feedback can identify implementation problems early and support real-time improvements.