Overcoming the Barriers to Recruitment of Underrepresented Minorities

Stephanie Williams

Stephanie Williams, MS, CCRC, Cincinnati Children's Hospital

Clinical Researcher—August 2018 (Volume 32, Issue 7)


Stephanie Lynn Williams, MS, CCRC


Racial and ethnic disparities among research subjects in clinical trials continue to persist despite the changing demographics in the United States.{1} The percentage of racial and ethnic minorities in the general population is steadily growing, but that growth is not reflected in clinical trials. There is vast literature confirming this underrepresentation, and much of it focuses on the existing barriers to subject participation.{2,3} The gold standard for clinical research continues to be randomized clinical trials, yet diversity in these trials remains extremely low and lack of representative sampling continues to be an issue.

In an attempt to correct this underrepresentation, the National Institutes of Health (NIH) mandated the inclusion of women and racial minorities with the passage of the Revitalization Act of 1993.{4} Recognizing the importance of including these groups, the Act was intended to increase the number of women and individuals from disadvantaged backgrounds, including racial and ethnic minorities, in the fields of biomedical and behavioral research and diversify research populations. The Act’s intended purpose has not been fully realized, and barriers continue to impact the enrollment of many racial and ethnic minority groups. Some insight as to why the Act has been less effective than anticipated will be discussed in the sections ahead, along with some of the known barriers to recruitment and ways to address these barriers.

Importance of Minority Participation

Racial and ethnic minorities currently make up 38.7% of the U.S. population, but estimates place the rate of inclusion in research studies between 2% and 16%.{5,6} The term racial and ethnic minorities in this context refers to anyone who is not considered “white alone” for purposes of census classification. According to the U.S. Census Bureau, the country’s diversity remains on the rise, with all racial and ethnic minorities growing faster than whites from 2015 to 2016.{7} Minority residents of the U.S. are expected to comprise more than 40% of the nation’s population by 2035, 47% by 2050, and 56% by 2060.{8}

The importance of minority participation in clinical trials has been garnering national attention in recent years. Countless articles and opinion pieces have been written on this topic, including a blog post from the U.S. Food and Drug Administration (FDA). As of the post, the FDA was planning a variety of activities to push for greater inclusion, including more minority participation. The author acknowledged FDA’s awareness that certain groups of patients may respond differently to different therapies, and that “a wide range of people should have the opportunity to participate in trials, both for access to new therapies and to have the chance to contribute to better treatment of everyone.”{9}

In his 2015 State of the Union address, President Obama announced the launch of the Precision Medicine Initiative (PMI), designed to revolutionize the approach to health improvement and disease treatment.{10} The PMI includes NIH’s “All of Us” program, an effort to recruit a large research cohort to advance individualized prevention, treatment, and care for people of all backgrounds. One of the core values of the program is that participants reflect the rich diversity of the U.S.{11} National enrollment officially opened for the program on May 6, 2018. The press release announcing the enrollment date stated that “the overall aim is to enroll 1 million or more volunteers and oversample communities that have been underrepresented in research to make the program the largest, most diverse resource of its kind.”{12}

There are also economic and social justice reasons for reducing these disparities. Eliminating racial and ethnic health disparities would have decreased U.S. medical costs by more than $1.2 trillion for the years 2003 to 2006. This estimate includes direct and indirect medical costs, such as loss of productivity, as well as the cost of premature death.{13} As of 2015, racial disparities continued to be associated with substantial annual economic losses nationally. Diversity in biomedical research often does not reflect the U.S. population, and in order to remain consistent with the values of our society, health-related disparities caused by this underrepresentation should be addressed.

The NIH Revitalization Act

The Revitalization Act is often referenced when discussing racial disparities and inadequate representation in clinical research. It was seen by many as a culmination of efforts to overcome the lack of representative sampling in clinical trials, and was anticipated to increase the enrollment of underrepresented groups. However, this was not the first act of legislation aimed at increasing enrollment in clinical trials, nor the first act addressing disparities in the health status of racial minorities in the U.S.

The National Research Act of 1974, enacted a mere two years after the public disclosure of the Tuskegee Syphilis Study, established ethical principles to govern clinical research and put protections in place for human subjects involved in research.{14} The Tuskegee Study is commonly perceived as the worst example of medical research exploitation in U.S. history, and was ongoing for 40 years (1932 to 1972). The U.S. government conducted the study on unknowing “subjects”—hundreds of African American men living in the Deep South who were excluded from life-saving treatment while being subjected to clinical testing so doctors could determine the natural progression of syphilis.{15} Unsurprisingly, death and disability for many men and their families resulted. Knowledge of this unethical exploitation contributes to the mistrust that some minority communities still feel today when it comes to research.

Other legislative acts followed, mostly in response to Congressional findings demonstrating a growing health disparity gap among racial minorities.{16} These disparities helped prompt the enactment of the Revitalization Act, which mandated the inclusion of racial minorities in clinical trials as a condition to receive federal funding and required that research participant characteristics be disclosed in research documentation as a way to measure inclusion.{2}

Twenty years after the implementation of the Revitalization Act, researchers assessed minority rates to see if the intended diversification had occurred in cancer clinical trials. The results showed that little progress had been made; the number of cancer trials with a primary emphasis on any racial or ethnic group was found to be less than 2%.{17} To put that in perspective, cancer is the second leading cause of death in the U.S., regardless of race or ethnicity.{18} Less than 5% of NIH-funded respiratory research reported inclusion of racial and ethnic minorities, and similar rates are found in cardiovascular and diabetes clinical trials.{19}

One major limitation of the Revitalization Act is that NIH guidelines only apply to federally funded trials. From 2006 through 2014, newly registered NIH-funded trials steadily decreased, with a few exceptions, whereas industry-funded trials increased substantially. In 2014, pharmaceutical companies funded 6,550 trials while NIH funded 1,048 trials.{20} A majority of clinical trials leading to drug approvals are funded by pharmaceutical companies which are not held to NIH guidelines and do not require increased enrollment of racial minorities.

Known Barriers to Recruitment

Barriers to recruitment can be identified through a variety of sources. Much research has gone into determining whether minorities are reluctant to participate in clinical research and discovering other barriers. Some of this research focuses on issues of mistrust stemming from past abuses like Tuskegee and the story of Henrietta Lacks, which has seen renewed interest in recent years following the film adaptation of a book about her life and beyond.{21} A poor African American woman, Lacks went to Johns Hopkins for treatment and without her knowledge or consent, her cancer cells were used and have now become one of the most important cell lines in medical research.{22} These types of research abuses involving minorities occurred prior to the establishment of many of the ethical requirements that now govern clinical research.

The identification of barriers to recruitment can come through prescreening interviews, research participant interactions, and literature review. Prescreening interviews are valuable interactions; potential research participants call a research site to see if they qualify for a trial, and while someone may meet the initial qualifications, that person may decide not to participate for various reasons. Those reasons are barriers to participation. Similarly, through participant interactions with enrolled subjects, barriers can be identified. A participant may enroll in a study and then miss visits or discontinue the study prematurely. The reasons why a participant fails to complete a trial can sometimes be barriers to consider. The literature also explores barriers that have been identified.

From the sources mentioned above, some identified barriers include lack of awareness, logistics, mistrust, lack of diversity among the research and clinical professionals, research not being conducted in the community, disconnect between researchers and the community, limited access to specialty centers that refer patients to clinical trials, minorities not being as willing to participate in research, and fear of exploitation in clinical research. Lack of awareness can include a lack of awareness in available trials or of clinical trials as therapeutic options. Logistics can include issues surrounding costs associated with participation, transportation, and convenience. Mistrust can include not wanting to be a “guinea pig” and mistrust of the medical or research fields in general. All or some of these barriers may apply at different times and to different groups, and it is common for some of the solutions addressing these barriers to overlap.

Overcoming Known Barriers

Identifying known barriers is the first step toward addressing them. Awareness of the minority populations in the recruitment area is essential so the appropriate recruitment methods can be employed. Depending on location in the country, minority populations will differ and recruitment considerations may change depending on the population sought.

To address the lack of awareness barrier, there are a number of proposed solutions. Lack of awareness can simply mean that people are not aware of the clinical trials available to them or are unaware that clinical trials are available for numerous medical conditions. Solutions to this barrier include advertising and education. Targeted advertising, for example on public transportation or in advertising forums specific to the targeted population, can be effective. This includes going to community healthcare providers to advertise or to educate providers on available trials, rather than relying on referrals from specialty centers or other medical institutions that may not be where the target population is receiving care. Education can also occur at community health events or town hall meetings.

To address the logistics barrier, concerns such as costs associated with participation, transportation, and inconvenience must be dealt with. Possible solutions to issues concerning cost include ensuring that studies are appropriately budgeted to account for time and commitment expectations.

Another way to address this issue is by providing travel or meal vouchers that may ease the financial burden. Travel vouchers also apply to the transportation barrier along with mindfulness of where the research site is located. Knowing whether a site is along a bus route, if there is ample parking, and if a site is easy to find are all aspects of participation that can be challenging to potential participants if unclear. Some research sites are located on huge academic campuses and can be daunting to someone visiting the institution for the first time, so providing clear directions to the actual location where the trial will be conducted within the institution is also important.

When it comes to inconvenience, extending office hours outside the typical “9 to 5” can allow working participants more flexibility and potentially increase the recruitment population. The option to conduct visits over the phone or at satellite locations can make visits more convenient.

Addressing mistrust really comes down to being transparent about what is being done for a particular trial, like what is expected of the participant, what research questions are being answered, and what benefits and risks are anticipated. Education about the research process and addressing specific concerns are key. Having enough information and knowledge about commonly known research exploitations and acknowledging past abuses if they come up add credibility to the team members conducting the research, and can go a long ways toward gaining the trust of potential participants. Transparency and education are some of the best tools to combat fear of exploitation.

Further, a lack of diversity in the research team has repeatedly been reported as problematic.{23} In the fields of science, technology, engineering, and math (STEM), there is a significant underrepresentation of minority students, resulting in fewer minority scientists and physicians.{24} Efforts to increase the numbers of minorities involved in STEM fields should be made to address this problem. Minority scientists and physicians are more likely to conduct research in minority populations, may more easily be able to gain the trust of those communities, and participants may be more likely to sign up for a clinical trial if the recruiter looks like them.{23}

Ways to address the barrier of a lack of diversity in the research team include recruiting research team members from diverse backgrounds, including community advocates and student workers. Other suggestions include ensuring that language options are available for the target demographic and considering a community-research liaison.

Barriers dealing with research outside the community or disconnect between researchers and the community can be addressed by taking the research project into the community. Attending community health events where researchers can talk to members of the community about available opportunities and allow the chance for questions can be beneficial for recruitment. Setting up mobile offices or establishing satellite locations within the community can also help to overcome this barrier. Researchers who go where the participants are rather than waiting for the participants to come to them may have more success reaching populations that have historically been underserved.

Minorities being less willing to participate in clinical trials may no longer be the barrier it once was perceived to be. Recent research suggests that racial and ethnic minorities are as willing as whites to participate in clinical research.{25} Accordingly, some of the other barriers discussed should be the future focus of increasing enrollment in underrepresented groups.


Increased clinical trial participation by racial and ethnic groups continues to be an imperative endeavor because diseases present differently in different groups of people, certain medications have been proven to be more or less effective depending on racial or ethnic background, and increasing diversity in clinical research will help ensure that medial products are safe and effective for everyone.{26} The NIH Revitalization Act attempted to address some of the racial disparities in clinical trial populations, but limitations have rendered the Act less effective than originally anticipated. Known barriers to recruiting underrepresented groups have been identified and suggested solutions have been proffered. Discovering ways to increase the enrollment of racial and ethnic minorities continues to be an issue worthy of further exploration.


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Stephanie Lynn Williams, MS, CCRC, (stephanie.williams@cchmc.org) is a senior regulatory affairs specialist with Cincinnati Children’s Hospital in Ohio.

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