Outcomes of Dyadic Recruitment in the PRIMA Trial Advance Cognitive Impairment Research

Why Dyadic Recruitment Matters in Cognitive Impairment Research

Cognitive impairment affects millions of older adults and is projected to impact 9.3 million Americans by 2060. Conditions such as mild cognitive impairment and subjective cognitive decline reduce participation in daily activities, lowering life satisfaction for both the individual and their caregiver. Caregivers often face substantial burdens, including managing medications, supporting social interactions, and handling executive function challenges that stem from memory issues.

Recruiting both members of a dyad together adds layers of complexity. Both parties must agree to participate, understand the study commitments, and navigate potential skepticism about research benefits. The pandemic further limited in-person outreach, making telephone-based and database-driven approaches essential. Effective recruitment ensures adequate sample sizes, maintains study validity, and avoids costly delays or underpowered results.

Core Methods and Multi-Channel Recruitment Strategies

The PRIMA team employed a combination of direct referrals, healthcare system databases, volunteer registries, advertisements, and partnerships with established organizations. Initial contact often began with mailed invitation letters, followed by telephone outreach. This sequence proved effective for building trust and allowing potential participants time to review materials before speaking with study staff.

Eligibility screening occurred via telephone, accommodating participants across state and national levels. The approach adapted to pandemic conditions by minimizing in-person requirements while maintaining rigorous consent and assessment processes. Partnerships with entities such as the Indiana Clinical and Translational Sciences Institute and local aging services organizations expanded reach without relying solely on clinical sites.

Most Effective Recruitment Sources and Their Performance

Analysis of enrollment data revealed clear patterns in source effectiveness. A healthcare system database accounted for 46 percent of successful initial contacts, screenings, and enrollments. A volunteer participant registry contributed 37 percent. These two resources outperformed others due to their large, pre-vetted pools of individuals already engaged with health systems or research opportunities.

Other channels, including in-clinic referrals and external advertisements, played supporting roles but yielded lower conversion rates. The combination of mailed letters and subsequent telephone calls enhanced response rates across sources. This hybrid method allowed the team to scale outreach efficiently while respecting participant preferences for remote engagement.

Enrollment Outcomes and Timeline Achievements

The trial successfully enrolled its target of 210 PwCI-CG dyads between October 2021 and August 2024. Enrollment averaged approximately 10 dyads per month, with acceleration in the later phases. Nearly 75 percent of participants joined during the final 16 months of the period, coinciding with the easing of pandemic restrictions and refined recruitment tactics.

Steady enrollment of about eight dyads per month continued after the World Health Organization declared the end of the COVID-19 public health emergency in May 2023. This consistent pace demonstrated the robustness of the adapted strategies and the value of ongoing monitoring to identify and address barriers promptly.

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Adaptations to Pandemic Constraints and Broader Challenges

The COVID-19 pandemic restricted traditional in-person recruitment common in behavioral intervention studies. The PRIMA team shifted emphasis to remote methods, leveraging telephone contact and digital registries. This transition enabled continued progress while protecting the health of vulnerable older adults and their caregivers.

Broader challenges included caregiver time constraints, potential skepticism from PwCI regarding research value, and the need for both dyad members to consent jointly. Memory and executive function difficulties sometimes complicated initial engagement. The use of mailed materials helped mitigate these issues by providing clear, low-pressure information.

Lessons Learned for Future Dyadic Studies

Several practical insights emerged from the PRIMA experience. Healthcare system databases and state-level volunteer registries offer scalable, high-yield sources for dyadic recruitment. Mailing invitation letters prior to telephone contact improves engagement rates. Telephone-based screening supports enrollment across wide geographic areas.

Researchers should monitor progress in real time, remain flexible with strategies, and cultivate partnerships with clinical data centers and community organizations. These steps help overcome the inherent difficulties of recruiting pairs rather than individuals. The approach also highlights the importance of tailoring communication to address caregiver burden and participant concerns about added demands.

Institutional Support and Funding Context

The PRIMA trial received primary funding through National Institutes of Health grant R01NR018162. Additional support came from the Indiana University Alzheimer’s Disease Research Center under grant P30AG010133. Recruitment infrastructure benefited from collaborations with the Indiana University Health Data Center, the Indiana Clinical and Translational Sciences Institute, and community partners such as the Alzheimer’s Association Greater Indianapolis Chapter and CICOA Aging and In-Home Solutions.

These institutional resources provided access to large patient databases, trained staff, and established community networks. Such backing proved instrumental in achieving enrollment targets despite external disruptions.

Implications for Alzheimer’s Research and Clinical Practice

Successful dyadic recruitment advances nonpharmacologic interventions aimed at improving quality of life for those affected by cognitive decline. The PRIMA findings underscore that targeted database and registry approaches can accelerate enrollment in similar behavioral trials. This efficiency supports the National Plan to Address Alzheimer’s Disease priority of developing effective non-drug therapies.

Broader application of these strategies may help other studies meet sample-size goals more reliably, reducing waste of research resources. The emphasis on telephone and mailed outreach also offers models for reaching underserved or geographically dispersed populations.

Future Outlook and Recommendations for Researchers

As cognitive impairment research continues to grow, investigators should prioritize multi-source recruitment plans that include healthcare databases and volunteer registries from the outset. Early piloting of mailing-plus-telephone sequences can refine messaging and timing. Ongoing evaluation of source performance allows timely adjustments.

Future trials may further integrate digital tools while maintaining personal contact elements that build trust. Collaboration across academic medical centers, community organizations, and national registries will likely remain key to scaling studies efficiently. The PRIMA experience provides a concrete blueprint for these efforts.

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Conclusion: Advancing Recruitment Science Through Real-World Results

The outcomes of dyadic recruitment in the PRIMA trial demonstrate that thoughtful, adaptive strategies can overcome significant barriers. By leveraging healthcare databases and volunteer registries, mailing preparatory materials, and employing telephone outreach, the team achieved its enrollment target of 210 dyads on schedule. These results, detailed in the peer-reviewed publication by Chang, Katz, Gao, Yang, Passey, Brehm, Apostolova, and Lu, offer actionable guidance for the research community. Continued refinement of such methods will strengthen future studies supporting older adults with cognitive impairment and their caregivers.