Creating Inclusive Eligibility Criteria to Promote Diversity in Clinical Trials

Eligibility criteria are foundational to the success of clinical trials. They define who can and cannot participate and directly influence the diversity, generalizability, and ethical integrity of a study. Overly narrow or restrictive inclusion and exclusion criteria often limit trial access for underrepresented populations, leading to skewed outcomes and regulatory scrutiny. To build equitable and scientifically valid studies, it is imperative to design eligibility criteria that balance participant safety with inclusive access.

This guide outlines best practices for designing inclusive eligibility criteria that meet global regulatory expectations, promote diversity, and enhance patient recruitment.

Why Inclusive Eligibility Matters

Eligibility criteria are often criticized for excluding key populations such as the elderly, women of childbearing potential, those with comorbidities, and racial or ethnic minorities. These exclusions not only compromise the external validity of a study but also limit treatment options for those populations post-approval.

Inclusive design enables:

• Improved generalizability: Results apply to broader populations.
• Regulatory compliance: Agencies like the EMA and USFDA require demographic representation data.
• Accelerated recruitment: Less restrictive criteria help reach targets faster.
• Ethical research: Equitable access promotes fairness and trust.

Global Regulatory Guidance on Inclusive Criteria

• USFDA: Recommends avoiding unnecessary exclusions and requires sponsors to submit a Diversity Action Plan for Phase 3 trials.
• EMA: Advises alignment with disease epidemiology and discourages exclusion of elderly or comorbid patients without justification.
• ICH E8(R1): Emphasizes fit-for-purpose design, inclusiveness, and real-world applicability.
• Health Canada: Encourages equity-focused inclusion that reflects Canada’s multicultural demographics.

Principles of Inclusive Eligibility Design

1. Justify every exclusion: If a population is excluded, provide evidence of risk or scientific rationale.
2. Align with real-world settings: Consider how the target population actually presents in clinics.
3. Account for common comorbidities: Especially in chronic diseases like diabetes, cardiovascular disorders, or HIV.
4. Enable decentralized participation: Remove geographic and mobility barriers using digital tools and home visits.
5. Use plain language: Ensure all eligibility documentation is accessible and understandable.

Examples of Exclusionary Practices and Alternatives

Operationalizing Inclusive Criteria in Protocols

• Conduct early feasibility analysis: Assess site capabilities and patient pool demographics.
• Engage community advisory boards: Include patient advocates during protocol development.
• Pilot inclusion criteria: Use small-scale simulations to test enrollment impacts.
• Define clear risk mitigation strategies: For populations with complex health profiles.
• Document assumptions: Include rationale in the trial protocol and investigator brochure.

Monitoring and Adjusting Criteria During the Trial

In adaptive and pragmatic trial designs, criteria may evolve based on interim data:

• Track screen failure rates by demographic subgroup
• Analyze dropout rates and adverse event trends by inclusion type
• Amend protocols when criteria unintentionally skew representation
• Use tools from Stability Studies to assess longitudinal performance of recruitment diversity

Technology as an Enabler of Inclusive Design

Digital platforms can support inclusive criteria by:

• Automating multilingual screening workflows
• Allowing flexible visit scheduling and virtual interactions
• Flagging potential bias in real-time analytics
• Linking to EHRs for eligibility pre-screening
• Documenting justification within validated systems (SOP validation in pharma)

Ethical and IRB Considerations

Institutional Review Boards (IRBs) review eligibility for fairness, safety, and scientific validity:

• Ensure no arbitrary or discriminatory exclusions
• Review demographic targets in the recruitment plan
• Confirm community and patient input has been incorporated
• Approve protocols with justifiable rationale for inclusion/exclusion

Case Study: Expanding Criteria in an Oncology Trial

A multicenter oncology trial initially limited participation to patients aged 18–70 with no prior comorbidities. Enrollment was slow and not representative of the population affected by the disease. Upon protocol amendment, the trial:

• Extended the age range to 80
• Allowed controlled hypertension and Type 2 diabetes
• Added telehealth visits for rural participants

As a result, enrollment increased by 35% within 3 months and racial diversity doubled.

Conclusion: Inclusivity Begins with Criteria

Eligibility criteria set the tone for who can access and benefit from clinical research. Overly narrow designs risk excluding those most affected by disease and jeopardizing both ethics and external validity. By embedding inclusivity into eligibility planning—from community input to technology tools—sponsors and researchers can meet regulatory expectations, strengthen recruitment, and ensure that trials serve all populations equitably.