Reviewed by the Help Dementia Editorial Team — our editors review every article for accuracy against guidance from the National Institute on Aging, the Alzheimer’s Association, and peer-reviewed sources.
Clinical trial sits at the center of this dementia and brain health question.
Clinical trial recruitment strategies are essential to ensuring that Alzheimer’s disease research reflects the actual populations affected by the disease. Without intentional and diverse recruitment efforts, clinical trials risk producing results that may not apply to the majority of people living with dementia. The fundamental challenge is straightforward: the Alzheimer’s disease field needs 50,000 or more participants to populate currently active clinical trials, with approximately 12,000 enrolling annually across a 2025 pipeline of 182 active trials, yet these trials have historically enrolled predominantly white participants, leaving critical questions unanswered about whether treatments work equally well across racial and ethnic groups. The statistics reveal an urgent problem.
Analysis of 101 Alzheimer’s disease trials conducted between 2001 and 2019 found that white participants made up a median of 94.7% of enrollees, with no significant improvement over those two decades. Meanwhile, Black Americans are nearly twice as likely as white Americans to develop Alzheimer’s dementia, and Latinx Americans are 1.5 times more likely to develop the disease. This mismatch between disease burden and research representation means that the drugs being developed and tested may not reflect the needs or biology of the communities most affected. For instance, in the landmark Lecanemab trial (CLARITY-AD), which led to the first disease-modifying Alzheimer’s drug approval, Black participants made up only 2.5% of the study population despite carrying a disproportionate disease burden.
Table of Contents
- Why Do Recruitment Challenges Persist in Alzheimer’s Clinical Trials?
- The Representation Crisis and What It Means for Alzheimer’s Care
- Identifying and Overcoming the Eligibility Bottleneck
- Community-Based Recruitment Strategies That Deliver Results
- The Reporting Gap and What It Reveals About the Field
- Biomarkers, Technology, and the Modernization of Recruitment
- Moving Forward—The Future of Representative Alzheimer’s Research
- Conclusion
- Frequently Asked Questions
Why Do Recruitment Challenges Persist in Alzheimer’s Clinical Trials?
The barriers to enrollment in Alzheimer’s disease trials run deeper than simple logistical hurdles. One major constraint is clinical eligibility: only 10 to 27 percent of Alzheimer’s disease patients actually qualify for clinical trials due to comorbidities, medication interactions, or cognitive status requirements. When a trial requires participants to have early-stage cognitive impairment and no history of stroke, diabetes complications, or liver disease, the pool of eligible candidates shrinks dramatically. This means recruiters are working with a fundamentally limited population, making diversity even harder to achieve unless they actively target underrepresented communities from the start. Systemic distrust and historical harm also play a critical role. Across Black and Latinx communities in the United States, decades of medical racism and research exploitation have created justified hesitation about clinical trial participation.
The legacy of unethical studies, from the Tuskegee syphilis experiment to more recent disparities in healthcare, means that traditional recruitment messages—even when well-intentioned—may not overcome legitimate concerns. Building trust requires more than a single recruitment push; it demands sustained, authentic relationships between research institutions and communities. Geographic and practical factors further complicate recruitment. Many Alzheimer’s disease trials require frequent hospital or clinic visits, cognitive testing, and neuroimaging procedures like positron emission tomography (PET) scans. For older adults without reliable transportation, living in rural areas, or managing other health conditions, these requirements can be prohibitive. Language barriers, limited awareness about trial opportunities, and lack of knowledge about Alzheimer’s disease itself can also reduce participation, particularly in communities with less access to healthcare information.
The Representation Crisis and What It Means for Alzheimer’s Care
The lack of diversity in Alzheimer’s disease trials is not simply a matter of fairness—it has direct implications for the effectiveness and safety of treatments across different populations. When nearly 50 percent of published clinical trials fail to even report the race and ethnicity of their participants, and only 4 percent of trials actually examine whether treatments worked differently across racial and ethnic groups, the field loses critical information about whether a drug approved based on a predominantly white study population will work as well or as safely in Black, Latinx, Asian, or Native American patients. The numbers from FDA-approved Alzheimer’s disease drugs illustrate the problem. In 2020, when analyzing trials that led to drug approvals, Black or African American participants represented only 8 percent of enrollees, Asian participants 6 percent, and Hispanic or Latino participants 11 percent. These figures do not match the racial and ethnic composition of the United States, nor do they match the prevalence of Alzheimer’s disease across communities.
The Lecanemab trial showed white participants at 76 percent, Hispanic participants at 12 percent, Black participants at 2.5 percent, and Asian participants at 17 percent (the latter inflated due to recruitment sites in Japan). This disparity raises legitimate questions: Are adverse effects more common in certain populations? Do dosing recommendations need adjustment for different genetic backgrounds? Without adequate representation, these questions remain unanswered until after drugs reach the market—or indefinitely. A related warning: the absence of diversity data in published trials makes it impossible for clinicians to counsel their patients about whether the evidence behind a medication actually applies to them. A physician treating a 72-year-old Black woman with early Alzheimer’s disease who wants to prescribe lecanemab is operating with trial evidence in which less than 3 percent of participants shared her racial background. That is a significant blind spot in precision medicine.
Identifying and Overcoming the Eligibility Bottleneck
Since only 10 to 27 percent of Alzheimer’s disease patients meet standard trial eligibility criteria, expanding and reconsidering those criteria is one avenue to increase recruitment. Trials with overly restrictive inclusion and exclusion criteria can inadvertently create a research population that differs from the broader Alzheimer’s disease population in ways that reduce generalizability. Some research institutions are beginning to ask whether certain criteria—such as strict medication washout periods or age cutoffs—are truly necessary for safety or whether they simply reflect convention. One promising approach is the use of Technology-Driven Recruitment Assessment (TDRA), which combines digital screening tools with human follow-up to improve enrollment rates. Studies using TDRA-assisted screening and study matching have achieved a 36 percent referral-to-enrollment rate, meaning roughly one in three people identified as potentially eligible actually enroll.
This is substantially better than traditional referral pathways and suggests that making the screening process more accessible and less burdensome can remove a significant barrier. Similarly, web-based recruitment models that allow digital screening and self-assessment have achieved 34 percent enrollment rates, allowing people to begin the trial process from home rather than requiring an initial office visit. The comparison between these strategies reveals an important insight: digital and technology-assisted approaches work, but they are not universally available or equally accessible. Not all Alzheimer’s disease patients have internet access, comfort with digital tools, or the support needed to complete online screening, particularly among older adults and in underserved communities. The most successful recruitment strategies likely combine digital convenience for those who can use it with in-person outreach and support for those who need it.
Community-Based Recruitment Strategies That Deliver Results
The most effective recruitment strategies for diverse Alzheimer’s disease trials share common elements: they involve on-the-ground, sustained relationships with communities rather than one-time advertising campaigns. Research presented at the 2024 Roundtable on Advancing the Science of Recruitment identified several critical success factors. First, recruiting and employing outreach staff that mirror the racial and ethnic identity of the target communities dramatically improves engagement. When a community health worker who shares a patient’s language, cultural background, and lived experience explains a trial, trust increases and hesitancy decreases.
Second, building partnerships with trusted local organizations—churches, community health centers, senior centers, and culturally specific organizations—provides a platform for recruitment conversations in spaces where people already gather. A recruitment event held at a neighborhood church carries more weight than a recruitment flyer mailed to a stranger’s home. Third, providing practical support such as transportation, meal support, and flexible visit scheduling removes barriers that would otherwise prevent participation. A concrete example of this approach is the work done through community health center networks in Los Angeles and other urban areas, where partnerships between academic medical centers and local primary care clinics serving predominantly Black and Latino communities have successfully enrolled more diverse cohorts of Alzheimer’s disease trial participants. When researchers worked through existing relationships and community trust, enrollment from underrepresented groups increased significantly compared to sites relying purely on direct-to-consumer advertising.
The Reporting Gap and What It Reveals About the Field
One of the most revealing—and troubling—aspects of the Alzheimer’s disease clinical trial landscape is the incomplete reporting of demographic data. Nearly 50 percent of published trials do not report the race and ethnicity of their participants at all. This omission serves as a warning sign: it suggests that diversity was either not tracked, not valued, or intentionally underemphasized in the research. When trials do report demographic data, the patterns reinforce historical disparities. The field has known for nearly a decade that representation in Alzheimer’s disease trials is heavily skewed toward white participants, yet the 2025 pipeline of 182 active trials suggests that while awareness is growing, systematic change remains slow.
Some trial sponsors and research institutions are now including diversity and inclusion plans in their proposals, making representation a quality measure rather than an afterthought. However, without mandates or enforcement mechanisms, progress depends on individual institutions prioritizing inclusivity. A related limitation worth noting: even when trials recruit diverse participants, the analysis and reporting of outcomes may not examine subgroups separately. Combining the results of a treatment across all participants obscures whether the drug works better or worse for specific populations. Future trials and analyses need to routinely examine whether cognitive benefits, side effect profiles, or disease progression differ by race, ethnicity, age, sex, or comorbidity status. Only then can the field move toward truly personalized medicine for Alzheimer’s disease.
Biomarkers, Technology, and the Modernization of Recruitment
The 2025 Alzheimer’s disease trial pipeline includes biomarker-based enrollment criteria in 57 percent of active trials, a significant increase from previous years. Biomarkers—such as amyloid, tau, and phosphorylated tau measured in blood, cerebrospinal fluid, or through PET imaging—allow researchers to identify people with Alzheimer’s disease pathology earlier, before symptoms progress. This shift creates both opportunity and risk for diversity. On one hand, blood-based biomarkers are more accessible and less burdensome than PET imaging, potentially broadening who can participate.
On the other hand, if only well-resourced research sites have access to biomarker testing, this could inadvertently exclude patients from under-resourced communities who lack preliminary diagnostic workup. Digital screening strategies combined with artificial intelligence and machine learning are being tested to accelerate recruitment and reach geographically dispersed populations. Trial sponsors are increasingly offering home-based computerized cognitive assessments and video conferencing for study visits, reducing the burden on participants and potentially increasing enrollment from rural and underserved areas. These innovations hold promise but require careful implementation to ensure equitable access and to avoid algorithmic bias in screening and matching processes.
Moving Forward—The Future of Representative Alzheimer’s Research
The field is at a turning point. The recognition that Alzheimer’s disease clinical trials have been unrepresentative is no longer a secret; it is acknowledged in major publications, funding agency priorities, and trial design guidelines. The National Institutes of Health and the FDA have made diversity in clinical research a priority, providing incentives and guidance for more inclusive trials. The 2024 Roundtable on Advancing the Science of Recruitment brought together researchers, trial sponsors, community members, and advocates to identify concrete barriers and solutions—a sign that systemic change is being attempted.
However, momentum and intention are not enough. Building representative Alzheimer’s disease clinical trials requires sustained funding for recruitment staff and community partnerships, implementation of flexible eligibility criteria, investment in digital and technology-assisted screening tools, and commitment to reporting and analyzing outcomes across demographic groups. The next generation of Alzheimer’s disease treatments will be developed in trials that include more diverse participants and provide more complete answers about who these treatments help, how well they work, and for whom they pose risks. That progress will make Alzheimer’s disease care more equitable and more precise for all.
Conclusion
Clinical trial recruitment strategies are the mechanism by which the field can ensure that Alzheimer’s disease research reflects the people it is meant to serve. The evidence is clear: without intentional recruitment in Black, Latinx, Asian, and other underrepresented communities; without addressing barriers to participation; and without reporting and analyzing results across demographic groups, the field will continue to develop drugs tested primarily on white participants and approved for use in a much more diverse population. This is a form of medical inequality that persists even in well-intentioned research.
The solutions are within reach. Technology-assisted recruitment, community partnerships, flexible trial design, and commitment to diversity in data reporting can expand and diversify Alzheimer’s disease clinical trial enrollment. The 182 active trials in the 2025 pipeline represent an opportunity: they can enroll the 50,000 participants needed to advance the field while simultaneously building more representative evidence. Whether the field seizes that opportunity depends on whether recruitment is treated as an afterthought or as central to research excellence and equity in dementia care.
Frequently Asked Questions
Why are Black and Latino Americans underrepresented in Alzheimer’s disease clinical trials if they have higher rates of the disease?
The underrepresentation stems from multiple factors: historical medical mistrust, eligibility criteria that may exclude people with common comorbidities, limited awareness of trial opportunities in these communities, lack of sustained recruitment relationships, and barriers such as transportation and visit frequency. It is not because disease rates are lower but because the recruitment infrastructure and trust required to engage these communities has been absent.
What percentage of Alzheimer’s disease patients can actually participate in a clinical trial?
Only 10 to 27 percent of Alzheimer’s disease patients meet standard trial eligibility criteria due to comorbidities, medication use, cognitive status, and other factors. This narrow eligibility pool makes targeted recruitment of underrepresented groups even more critical, as it reduces the overall population available for enrollment.
How do web-based recruitment and digital screening compare to traditional methods?
Web-based recruitment models achieve a 34 percent enrollment rate, while traditional referral-assisted methods with digital screening achieve a 36 percent referral-to-enrollment rate. Both are significantly more effective than passive advertising but require accessible digital infrastructure and support for people less comfortable with technology.
What happens if a clinical trial does not report the race and ethnicity of participants?
It becomes impossible to know whether the trial results apply equally to all communities and whether the drug works as well, as safely, or in the same way across racial and ethnic groups. This is a critical gap because treatments may have different efficacy or side effect profiles depending on genetic background and other factors.
Are newer Alzheimer’s disease drugs like lecanemab tested in diverse populations?
The lecanemab trial (CLARITY-AD) included 76 percent white participants, 12 percent Hispanic, 2.5 percent Black, and 17 percent Asian participants. While Asian representation was higher due to recruitment in Japan, Black representation was notably low given the higher prevalence of Alzheimer’s disease in Black communities, highlighting the ongoing diversity gap.
What is the role of community health workers in recruitment?
Community health workers who mirror the racial and ethnic identity of target communities and work through trusted local organizations dramatically increase recruitment success. They build trust, provide culturally tailored information, and remove barriers such as transportation and scheduling inflexibility. They are considered critical to achieving diverse enrollment.
You Might Also Like
- Multi-Modal Alzheimer’s Treatment Strategies Show Improved Outcomes
- Drug Utilization Studies Track Real-World Alzheimer’s Treatment Patterns
- Drug Utilization Studies Track Real-World Alzheimer’s Treatment Patterns
For more, see Alzheimer’s Association — medical tests.
