Disparities by Race and Ethnicity Among Adults Recruited for a Preclinical Alzheimer Disease Trial

Key Points

Question

Are there racial/ethnic differences associated with recruitment sources and reasons for ineligibility among preclinical Alzheimer disease clinical trial participants?

Findings

In this cross-sectional study of screening data for 5945 participants from a preclinical Alzheimer disease trial, Black, Hispanic, and Asian participants were recruited from local efforts compared with White participants who were recruited from more distributed efforts. Adjusted analysis showed that underrepresented racial/ethnic communities were more likely to be ineligible after the first screening visit.

Meaning

These findings suggest that there are racial and ethnic disparities in preclinical AD clinical trial enrollment that will require a comprehensive approach to study design and recruitment strategies to minimize disproportionate enrollment.

Abstract

This cross-sectional study of screening data from a preclinical Alzheimer disease trial assesses differences in recruitment strategies and trial eligibility among racial and ethnic groups.

Abstract

Importance

Underrepresentation of many racial/ethnic groups in Alzheimer disease (AD) clinical trials limits generalizability of results and hinders opportunities to examine potential effect modification of candidate treatments.

Objective

To examine racial and ethnic differences in recruitment methods and trial eligibility in a multisite preclinical AD trial.

Design, Setting, and Participants

This cross-sectional study analyzed screening data from the Anti-Amyloid in Asymptomatic AD study, collected from April 2014 to December 2017. Participants were categorized into 5 mutually exclusive ethnic/racial groups (ie, Hispanic, Black, White, Asian, and other) using participant self-report. Data were analyzed from May through December 2020 and included 5945 cognitively unimpaired older adults between the ages of 65 and 85 years screened at North American study sites.

Main Outcomes and Measures

Primary outcomes included recruitment sources, study eligibility, and ineligibility reasons. To assess the probability of trial eligibility, regression analyses were performed for the likelihood of being eligible after the first screening visit involving clinical and cognitive assessments.

Results

Screening data were included for 5945 participants at North American sites (mean [SD] age, 71.7 [4.9] years; 3524 women [59.3%]; 5107 White [85.9%], 323 Black [5.4%], 261 Hispanic [4.4%], 112 Asian [1.9%], and 142 [2.4%] who reported race or ethnicity as other). Recruitment sources differed by race and ethnicity. While White participants were recruited through a variety of sources, site local recruitment efforts resulted in the majority of Black (218 [69.2%]), Hispanic (154 [59.7%]), and Asian (61 [55.5%]) participants. Participants from underrepresented groups had lower mean years of education (eg, mean [SD] years: Hispanic participants, 15.5 [3.2] years vs White participants, 16.7 [2.8] years) and more frequently were women (226 [70.0%] Black participants vs 1364 [58.5%] White participants), were unmarried (184 [56.9%] Black participants vs 1364 [26.7%] White participants), and had nonspousal study partners (237 [73.4%] Black participants vs 2147 [42.0%] White participants). They were more frequently excluded for failure to meet cognitive inclusion criteria (eg, screen failures by specific inclusion criteria: 147 [45.5%] Black participants vs 1338 [26.2%] White participants). Compared with White participants, Black (odds ratio [OR], 0.43; 95% CI, 0.34-0.54; P < .001), Hispanic (OR, 0.53; 95% CI, 0.41-0.69; P < .001), and Asian participants (OR, 0.56; 95% CI, 0.38-0.82; P = .003) were less likely to be eligible after screening visit 1.

Conclusions and Relevance

Racial/ethnic groups differed in sources of recruitment, reasons for screen failure, and overall probability of eligibility in a preclinical AD trial. These results highlight the need for improved recruitment strategies and careful consideration of eligibility criteria when planning preclinical AD clinical trials.