Highlight
1. Small guaranteed financial incentives significantly increase enrollment in an Alzheimer’s prevention registry compared to invitations without incentives.
2. Lottery-based financial incentives with a chance to win a larger prize did not improve enrollment rates.
3. Economic diversity among participants increased, but racial and ethnic minority representation did not significantly improve.
4. White males responded most positively to small guaranteed incentives, indicating variable effectiveness across demographic groups.
Study Background and Disease Burden
Dementia, including Alzheimer disease (AD), poses a substantial public health burden characterized by progressive cognitive decline leading to disability and death. Marginalized racial and ethnic populations and individuals of low socioeconomic status experience higher dementia incidence but are substantially underrepresented in clinical research. This underrepresentation hampers the generalizability of findings and equity in the development of effective preventive and therapeutic interventions. Consequently, innovative strategies to increase the participation of diverse populations in AD clinical studies, including observational registries that facilitate trial recruitment, are urgently needed. Financial incentives have been proposed as one approach to enhance enrollment, yet their effectiveness across various incentive types and demographic groups remains understudied.
Study Design
This randomized clinical trial evaluated the impact of financial incentives on enrollment into the Alzheimer Prevention Trials (APT) Webstudy, an online observational registry designed to accelerate recruitment for AD clinical trials. The study population comprised 44,844 patients aged 50 years or older without dementia diagnoses, receiving care through a single integrated county health system including a hospital and nine outpatient centers.
Participants were randomized in a 1:1:1 ratio to three invitation arms: (1) a message-only invitation; (2) a message with a guaranteed $25 enrollment incentive; and (3) a message offering entry into a lottery with a $2,500 prize and 1 in 100 odds of winning. The primary outcome was enrollment, defined as registration into the APT Webstudy coupled with completion of at least one of two remote cognitive assessments. Invitations were sent between March 1 and April 24, 2024, with outcomes assessed through April 30, 2024.
Key Findings
Among the 44,844 individuals invited, demographic characteristics included a mean age of 64.7 years (SD 10.1), 56.8% women, and 55.8% Medicaid-insured. Racial and ethnic composition was 25.3% Hispanic/Latino, 21.2% non-Hispanic Asian, 13.5% non-Hispanic Black, and 27% non-Hispanic White.
Overall enrollment was low, with 401 participants (0.9%) completing registration and cognitive assessments. Relative to the message-only arm, the small guaranteed $25 incentive increased enrollment likelihood (adjusted odds ratio [OR] 1.39, 95% CI 1.09–1.76, P = .008), whereas the lottery incentive did not (adjusted OR 1.08, 95% CI 0.84–1.39, P > .99). Notably, enrollment in the lottery arm was significantly lower than in the small incentive arm (adjusted OR 0.78, 95% CI 0.61–0.98, P = .04).
Secondary analyses shed light on demographic responsiveness: White participants (adjusted OR 1.61, 95% CI 1.15–2.25, P = .006) and males (adjusted OR 2.40, 95% CI 1.55–3.75, P < .001) exhibited the strongest positive response to the $25 incentive compared to message-only. There was no significant evidence that either financial incentive improved enrollment among racial and ethnic minority groups or led to a more racially diverse cohort.
Expert Commentary
This large pragmatic trial demonstrates that small guaranteed financial incentives can modestly enhance recruitment into AD prevention registries within economically disadvantaged populations. The lack of impact from lottery-based incentives challenges assumptions that potential high-value rewards motivate at-risk older adults to participate.
Interestingly, despite targeting a diverse safety-net population, increased enrollment was predominantly among White males, underscoring persistent barriers to minority engagement beyond financial motivation alone. Factors such as mistrust, health literacy, accessibility, and cultural relevance likely contribute to underrepresentation and warrant multifaceted interventions.
Limitations include a relatively short recruitment period, a low absolute enrollment rate, and reliance on a single health system, which may affect generalizability. Remote cognitive assessments as part of enrollment might also differentially impact participation willingness.
These findings align with behavioral economics where guaranteed incentives often outperform probabilistic rewards in certain populations, yet reveal the complexity in addressing racial disparities in research participation.
Conclusion
Guaranteed small financial incentives modestly increased enrollment in an Alzheimer’s prevention registry among older adults with economic disadvantage but did not enhance racial or ethnic minority representation. Lottery-based incentives were not effective. Enhancement of recruitment diversity in dementia research likely requires multifactorial strategies addressing trust, accessibility, and cultural barriers in addition to financial considerations. Ongoing research should focus on tailored, community-engaged approaches to bridge the gap in inclusive clinical trial enrollment crucial for equitable dementia prevention and care advancements.
References
1. Jacobson M, Molina-Henry D, Chang TY, et al. Financial Incentives to Increase Diversity of Older Participants in a Memory Concerns Registry: A Randomized Clinical Trial. JAMA Health Forum. 2025;6(8):e252273. doi:10.1001/jamahealthforum.2025.2273
2. Grill JD, Galvin JE. Facilitating Alzheimer Disease Research Recruitment. Alzheimer Dis Assoc Disord. 2014;28(1):1-8. doi:10.1097/WAD.0000000000000004
3. Quinn T, Keenan J, Gillard P, et al. Strategies to Enhance Recruitment of Older Adults to Clinical Research: Systematic Review and Meta-analysis. J Am Geriatr Soc. 2021;69(3):804-816. doi:10.1111/jgs.17013
