Financial Incentives to Increase Diversity of Older Participants in a Memory Concerns Registry: A Randomized Clinical Trial.

Importance: Persons from marginalized racial and ethnic groups and of low socioeconomic status are at high risk of dementia but are underrepresented in clinical trials. Financial incentives may improve representation. Objective: To evaluate the effect of financial incentives on enrollment of county health system patients into a memory concerns registry. Design, Setting, and Participants: Between March 1, 2024, and April 24, 2024, patients 50 years and older without a dementia diagnosis within a single integrated county health system that includes a hospital and 9 outpatient health centers were invited to enroll in the Alzheimer Prevention Trials (APT) Webstudy, an online observational study aimed at accelerating enrollment into Alzheimer disease clinical trials. Interventions: Patients were randomized 1:1:1 to an invitation message (arm 1), a message with a small ($25) enrollment incentive (arm 2), or a message with an enrollment incentive of entry into a $2500 lottery with 1 in 100 odds of award (arm 3). Main Outcomes and Measures: The primary outcome was enrollment, defined as APT Webstudy registration and completion of at least 1 of 2 remote cognitive assessments. Outcomes were measured through April 30, 2024. Results: Of 44 844 patients invited to the APT Webstudy, the mean (SD) age was 64.7 (10.1) years, 25 447 (56.8%) were women, 25 044 (55.8%) had Medicaid insurance, 11 347 (25.3%) were Hispanic/Latino, 9526 (21.2%) were non-Hispanic Asian, 6044 (13.5%) were non-Hispanic Black, and 12 109 (27%) were non-Hispanic White. A total of 401 participants (0.9%) enrolled in the APT Webstudy. Relative to the message-only arm, participants randomized to the small incentive arm were more likely to enroll (adjusted odds ratio [OR], 1.39; 95% CI, 1.09-1.76; P = .008) in the APT Webstudy while those in the prize incentive arm were not more likely to enroll (adjusted OR, 1.08; 95% CI, 0.84-1.39; P > .99). Enrollment in the prize incentive arm was lower relative to the small incentive arm (adjusted OR, 0.78; 95% CI, 0.61-0.98; P = .04). Secondary heterogeneity analyses indicated that patients of White race (adjusted OR, 1.61; 95% CI, 1.15-2.25; P = .006) and male sex (adjusted OR, 2.40; 95% CI, 1.55-3.75; P < .001) were most responsive to the small $25 incentive relative to the message-only arm. Conclusions and Relevance: In this randomized clinical trial, relative to message invitations, invitations with guaranteed, small financial incentives but not lottery incentives increased enrollment of economically but not necessarily racially or ethnically diverse participants to a study that aimed to increase enrollment in clinical studies. Trial Registration: ClinicalTrials.gov Identifier: NCT06033066.