Just as clinical researchers in other therapeutic areas have renewed their commitment to improving participant diversity in clinical trials, so too have those working in Alzheimer’s research.
African Americans are twice as likely to be diagnosed with dementia compared to Caucasians, but make up just five percent of all clinical trial participants. Similarly, older Latino and Hispanic individuals are 1.5 times more likely than white Americans to suffer from dementia, less than one percent have participated in a National Institutes of Health (NIH) clinical trial.
Without trials that reflect the diverse range of ethnicities that are affected by Alzheimer’s disease and other dementias, treatments currently in development are likely to only benefit the predominantly white population of those willing to participate in clinical research. However, increasing diversity in Alzheimer’s trials is a multifactorial issue that requires understanding and solutions that address the many factors at play.
“There is a well-recognized need for diversity in clinical trial populations to ensure diagnostics and treatments are safe and effective for everyone,” said Dr. Carl V. Hill, Alzheimer’s Association chief diversity, equity and inclusion officer, in a press release.
“It’s imperative that the Alzheimer’s community is aware of the impact of historical racism, and also the current racial discrimination in healthcare that presents obstacles for inclusive participation in Alzheimer’s trials. And, just as important, it is critical that we evaluate strategies that have been shown to be effective when recruiting historically underrepresented individuals and communities in these vital Alzheimer’s research studies,” he went on to say.
Fortunately, there are a number of researchers working on this issue. At the Alzheimer’s Association International Conference (AAIC) 2021, a multidisciplinary team of researchers shared their findings on what prevents minorities from participating in Alzheimer’s clinical research, and have developed new tools to address this disparity.
Which Factors Promote Alzheimer’s Clinical Trial Participation?
With many variables — including trust in the medical establishment, financial burden and fears of being a “guinea pig” — impacting an individual’s willingness to participate in clinical trials, researchers at the University of Wisconsin conducted the Voices Heard Survey to determine what factors positively impact the decision to volunteer. The survey respondents included 406 Wisconsin adults who were evenly distributed across four diverse ethnicities: white (100), African American (105), Latino (100) and Indigenous (101).
The research team identified three factors that were highly associated with participants being open to volunteering for a trial, regardless of race. Eighty-five percent of respondents said they were more likely to take part in biomedical research if they were directly invited to participate, and 83 percent shared they’d be willing if they agreed with the research goal. Having a family member with the disease was identified as the third most important factor influencing the willingness to participate, with 74 percent of those surveyed having highlighted the option.
However, the most interesting findings were the differences between white respondents and people of the three other ethnicities included in the study. Black, Latino and Indigenous individuals were more likely to say that being invited to participate in a trial by a person of their own race would make them more likely to consider volunteering — a finding not observed in the white survey respondents. Concerns over transportation to study sites, the availability of childcare and how participation in the trial might affect their ability to perform work and family tasks also factored more heavily among minority respondents than their white counterparts.
“We identified opportunities for tailored messaging designed to increase awareness of the value of Alzheimer’s research participation,” said Dr. Dorothy Farrar Edwards, faculty director of the University of Wisconsin Collaborative Center for Health Equity and investigator and outreach, recruitment and engagement core leader for the Wisconsin Alzheimer’s Disease Research Center. “As we get better at recruiting diverse populations, it will increase the urgency to get the conduct of trials right.”
Directly addressing the concerns of prospective minority participants in trials is key to fostering diversity in clinical trials.
Exclusion Criteria May Inadvertently Exclude on the Basis of Race
While identifying factors that promote clinical trial participation among diverse groups is an important step in helping to improve the diversity of research participants, even willing individuals can be excluded from participating during study enrollment. Some researchers have found that the list of exclusion criteria for a given trial — an important tool in ensuring data validity and protecting patient safety — may be inadvertently excluding minority participants from biomedical research, preventing diversity in clinical trials.
Recently, researchers at the National Institute on Aging (NIA), a division of the National Institutes of Health (NIH), looked at 235 ongoing Alzheimer’s and dementia clinical trials to determine which criteria were most commonly used, and whether they had the propensity to exclude more African American and Hispanic individuals from studies, compared to prospective white participants. Their findings: 60 percent of trials included exclusion criteria that could disproportionately apply to these minority participants.
This analysis was based on the identification of over 2,700 individual exclusion criteria that the research team organized into 56 categories. On average, drug trials had the highest number of exclusion criteria at around 18 per study — owing to the fact that studies investigating pharmacological treatment require more stringent enrollment practices — with other studies having an average of between 11 and 12 exclusion criteria.
Some of the most common exclusion criteria used in these trials were classified into the broadly-defined medical, neurological and psychiatric categories, which are subjective enough to rely on study investigators to “make the call” regarding an individual participant’s eligibility. Compared to the most common category — dementia/cognitive impairment — which was identified in nearly half of all trials involved in this analysis, the other commonly used exclusion criteria were far less objective and, therefore, subject to bias, whether intentional or not.
“This analysis is helping us ask an important question: Can we strengthen our criteria for clinical trials to maximize the number of eligible people from diverse and under-represented communities?” said Alexandra Mitchell, clinical research coordinator at NIA, in the same release. “We hope the Alzheimer’s community will take a closer look and can mimic the success in the oncology field where a concerted effort resulted in reworded, more equitable exclusion criteria.”
Building Outreach Materials That Target Underserved Populations
Putting these learnings into the ways in which participant diversity in Alzheimer’s trials can truly be achieved is the ultimate goal. One step toward that aim is the introduction of the NIA’s new clinical trial recruitment tool, Outreach Pro. By providing clinicians and those involved in the trials process with a tool to design culturally appropriate outreach materials, the hope is that they’ll be able to achieve increased awareness of Alzheimer’s disease, the trials process and current studies that are actively recruiting new participants.
“It is critical that clinical trials have appropriate representation to ensure that we have a complete understanding of how well different therapies or approaches to dementia care work in different populations,” said Dr. Holly Massett, senior advisor on clinical research recruitment and engagement at NIA, who oversees the implementation of the national strategy, in the same release. “Outreach Pro was designed to provide well-tested and culturally appropriate outreach materials that resonate with diverse populations and encourage them to participate in clinical trials.”
With the ability to create a range of trial recruitment materials, from websites and videos to social media posts and handouts, Outreach Pro is an important tool in improving enrollment from traditionally underrepresented communities, thereby increasing diversity in clinical trials. And while their library of well-tested materials currently includes those in English and Spanish designed to target the African American and Hispanic/Latino communities, the developers plan to add more diverse material catered toward Asian Americans and Pacific Islanders, along with Indigenous and Alaska Native communities by late 2021 and 2022, respectively.
Lack of Diversity in Clinical Trials Mirrors Other Cultural Inequities
For its part, the Alzheimer’s Association is running two studies with built-in participant diversity goals to understand how lifestyle interventions and imaging affect outcomes in African American and Latino participants. The first, dubbed the New IDEAS study, is a large trial investigating how a brain amyloid PET scan could affect how patients are diagnosed and treated for dementia. The goal of this study is to recruit 2,000 African American and 2,000 Latino volunteers to specifically look at clinical care outcomes in these communities that are often more affected by Alzheimer’s and other dementias.
The second is the US Study to Protect Brain Health Through Lifestyle Intervention to Reduce Risk (US POINTER), an interventional trial investigating how various lifestyle factors can influence risk of cognitive decline in a diverse group of older adults between the ages of 60 and 79.
And while all of these initiatives are promising, there’s still a long way to go to ensure that diverse trials become the norm. In particular, the persistent inequities that exist in healthcare in the US in general, like fewer Black and Hispanic Americans having health insurance coverage, must be addressed as part of the greater conversations and actions around improving diversity in clinical trials in disease research for Alzheimer’s treatments.