BRIDGe recruitment strategies for frail older adults in intervention trials: lessons learned from the ACTIVE-AGE@home trial

Background: Recruiting frail older adults is challenging, resulting in underpowered trials, wasted resources, and unexpected costs. Researchers rarely report transparently and comprehensively on recruitment. However, sharing recruitment experiences could improve future efforts. This study tracks recruitment efforts and assesses their impact on recruitment outcomes in the ACTIVE-AGE@home trial to develop effective strategies for engaging community-dwelling frail older adults in long-term trials. Methods: A mixed-method study assessed recruitment partner contacts and their respective influence on recruitment outcomes at three levels: macro-, meso-, and micro-level contacts. Quantitative data were used to measure strategy efficiency. Qualitative data consisted of field notes, personal annotations recorded by the researchers during 15 months recruitment for ACTIVE-AGE@home. These notes were analyzed thematically following Braun and Clarke’s approach: deductively, guided by the TIBaR model for recruiting hard-to-reach older adults (emphasizing building Trust, offering Incentives, identifying Barriers, and being Responsive), and inductively to explore themes related to prolonged engagement, adherence and maintenance. Results: Over 15 months, 49 macro-level, 112 meso-level, and 1001 micro-level recruitment partners were contacted. Of these, 30 meso-level and 44 micro-level partners referred frail older adults. Micro-level referrals yielded the greatest number of eligible participants, with 6 (meso-level) and 23 (micro-level) included. The study introduced the “BRIDGe recruitment model” with the following themes: (1) being appealing (2), fostering reciprocal relationships (3), understanding the recruitment partner and target group identity, and (4) gear trial requirements. The BRIDGe model serves as a reflective tool to balance recruitment and identity needs with trial requirements. Conclusions: Micro-level recruitment strategies are crucial for reaching frail older adults through warm referrals and personal contact. A bottom-up approach targeting local healthcare and welfare workers is recommended, with macro- and meso-level contacts supporting these connections. Rigid study designs hinder recruitment and translating research into practice requires flexible methods. Therefore, balancing rigor and feasibility is essential when designing context-specific studies. By transparently sharing recruitment successes and challenges, we aim to build collective knowledge to overcome recruitment barriers for frail older adults in intervention trials. Trial registration: The ACTIVEAGE@home trial was registered on ClinicalTrials.gov on July 6, 2023, and published July 14, 2023. Trial registration NCT05946109.