Diversity in Clinical Trials: The Role of Language Services


Diversity in Clinical Trials: The Role of Language Services

Clinical trials serve as the cornerstone of medical research. They provide evidence that helps determine the safety and efficacy of investigational medical products (IMPs) and novel treatments. The validity of this evidence, however, relies heavily on the diversity of participants. Because biological, genetic, social, and other factors can impact the efficacy and tolerability of certain products in specific populations, enrollment should always reflect the diversity of the target population of an IMP.

Racial and ethnic minorities often face a disproportionate burden for certain diseases and frequently experience limited access to care. These populations are also generally underrepresented in biomedical research. Thankfully, various research organizations and regulatory authorities are trying to change this. In the EU, the EU Clinical Trial Regulation No 536/2014 took effect in 2022. It prescribes an increased emphasis on clinical trial diversification to more fairly represent the population groups most likely to use the investigational product being studied, including pregnant people. Also, in 2022, the FDA sought to address the issue in its draft guidance “Diversity Plans to Improve Enrollment of Participants from Underrepresented Racial and Ethnic Subgroups in Clinical Trials,” which requires sponsors to develop and submit diversity plans during early clinical development.

Why the Lack of Diversity?

Poor diversity in clinical trials is linked to a multitude of challenges. Among racial and ethnic minorities, there can be a lack of trust in the medical community. In the United States, this can, in part, be traced to historical injustices such as the infamous Tuskegee Syphilis Study. It can also result from a lack of representation among clinical trial staff and investigators, among many other factors.

Minority communities also experience a lack of awareness due to insufficient outreach. Access issues such as difficulties accessing transportation or living in neighborhoods far from study sites can be present. Members of minority groups may also face constraints on their time and resources. Examples include inaccessibility or unaffordability of childcare or an inability to take time off work. Elderly and disabled participants might face additional challenges accessing study sites or assistance.

In addition, literacy and health literacy levels, language and cultural barriers, and religious beliefs can discourage participation. In terms of the LGBTQIA+ community, insufficient attention to inclusive language in recruitment materials and insufficiently inclusive protocol design are problematic.

Often, outreach and recruitment efforts fail to address these difficulties adequately.

The Importance of Diversity in Clinical Trials

Too little diversity in clinical trials negatively impacts research findings’ validity and generalizability. Different people may respond very differently to the same product according to their race, ethnicity, gender, weight, age, and other factors. If populations are underrepresented or excluded, it is impossible to determine how these groups will respond to treatment, leaving HCPs ill-informed about how best to treat specific patients. This lack of research then impairs efforts to address health disparities and inequities.

Certain populations are also at higher risk for specific behaviors and conditions. We also know that there are complex disparities in obesity rates and risk factors among different ethnicities. Some studies have also shown differences in how people of Asian descent respond to a variety of common drugs, such as anticoagulants, antidepressants, and antihistamines, due to reduced CYP2D6 activity compared to non-Asian populations. And we are beginning to see that genetic factors such as cholesterol abnormalities and a propensity for storing fat differently may be partially to blame for an increased risk of cardiovascular disease (CVD) in South Asian populations.

The lack of representation in clinical trials is problematic as opportunities are missed to research how specific interventions’ safety, efficacy, or feasibility might differ in various populations. Having this information would be invaluable for informing not only decisions by patients and providers but also for determining public health strategies.

Strategies for Recruitment and Retention

Diversity and inclusion should be addressed early in the planning process using various strategies, such as:

  • Gathering information about the needs and preferences of diverse populations using focus groups, surveys, and interviews. This should occur before recruitment planning begins so the findings can be incorporated into targeted advertising, protocol, and trial design.
  • Establishing an advisory panel that reflects the diversity of the community to provide ongoing strategic input.
  • Connecting with HCPs, advocacy groups, and non-profit organizations with established relationships and credibility within target communities. These can help educate and support communities and identify and refer potential participants. They can also help address any concerns from the community if they arise.
  • Recruiting staff from underserved groups.
  • Partnering with recruitment organizations that have experience reaching out to diverse audiences.
  • Conducting targeted outreach by ensuring recruitment campaign content is culturally and linguistically tailored to the target audience.
  • Providing flexible scheduling options and transportation to improve access.
  • Prioritizing feedback, regular communication, and trust-building with participants to ensure open communication channels in case of any issues during the trial.
  • Improving the cultural competency and sensitivity of clinical trial staff through training.
  • Making interpretation services available to participants at no cost, if needed.

Language and Culture: Keys to Success

Language and culture must be at the core of any effort to enhance diversity, equity, and inclusion in clinical trials. In monolingual trials, recruitment materials and all patient-facing content must be written in plain language to facilitate understanding. In addition, gender-inclusive language should be used.

When conducting multinational and decentralized clinical trials (DCTs) and trials that involve speakers of other languages, this is an even more crucial consideration. The FDA and EU authorities require sponsors to provide patient-facing material in a language the participant understands. This requirement means accurate professional translation of materials such as ICFs and plain-language summaries and an in-depth cultural awareness are required.

Specific populations may hold religious beliefs or have cultural norms that would bias them against specific procedures or visits. For instance, a female participant who is Muslim may not be willing to visit a study site where male physicians or nurses are providing care.

Differences in health beliefs, communication styles, and expectations can further hamper communication. Trial staff should be well-versed in cross-cultural communication and equipped to approach participants with cultural sensitivity to minimize these issues and build trust.


Patient-facing apps and other digital health products (DHPs) are increasingly used to conduct clinical trials. These must be localized – translated into the patient’s language and adapted to cultural expectations – to ensure that all participants fully understand what the trial entails, what the procedures and expectations are, and what rights they have.

Role of Language Service Providers

Specialized language service providers (LSPs) can help overcome the linguistic and cultural challenges that impede diversity in clinical trials. Serving as vital partners in developing a diversity plan, specialized LSPs have vetted and specialized translators and localization experts on hand. They can provide translation and localization services and coordinate multilingual content development. LSPs can also provide on-site or remote interpreters to assist with participant interactions, significantly contributing to recruitment and retention efforts.


Participant diversity is critical to achieving equitable representation in the clinical trial landscape. Sponsors must proactively plan outreach, enrollment, and retention strategies for diverse communities to make progress toward overcoming long-standing inequities. This approach will also allow them to gain valuable research and product development insights.

From a regulatory and patient-centric perspective, such strategies must extend to careful deliberation about professional translation, language access, and culturally sensitive localization. Qualified LSPs have the necessary experience and depth of expertise to help draw up and execute a plan to help ensure successful and diverse clinical trials.

Contact us today to learn more about how Vistatec can support your efforts to enhance diversity in clinical trials.