The Latest Evidence on Informed Consent in Clinical Trials

Informed consent in clinical trials is intended to protect participants and support ethical research, but how consistently is it reported and implemented?

The latest evidence shows wide variation in how informed consent is described, despite its central role in participant protection. The findings suggest that better reporting and more participant-centred consent approaches could strengthen transparency, trust, and trial quality.

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Why Informed Consent Still Matters in Modern Clinical Trials

Every clinical trial depends on participants making a voluntary and informed decision about whether to take part.

Informed consent is more than a signed document. It is an ongoing communication process that explains the purpose of the study, potential benefits, possible risks, available alternatives, and participant rights.

International guidance, including the Declaration of Helsinki, ICH Good Clinical Practice (ICH E6), and national regulatory frameworks, places informed consent at the centre of ethical clinical research.

Despite these well-established standards, a recent systematic review found that published trial reports often provide limited information about how informed consent was actually obtained, making it difficult to evaluate the quality of participant engagement.

What Did the Evidence Find About Informed Consent?

The evidence is from a systematic review of 149 randomised clinical trials published between 2022 and 2023 in five of the world’s highest-impact general medical journals.

Together, these studies represented thousands of research participants across a wide range of therapeutic areas.

While every trial stated that informed consent had been obtained, the review found that reporting on how consent was actually obtained was remarkably limited.

Only a small minority of publications described important aspects of the consent process beyond confirming that written consent had been obtained.

Evidence at a glance

The Biggest Gap Was Not Consent; It Was Transparency

One of the review's most important findings was that obtaining informed consent is no longer the issue. Instead, the challenge lies in understanding how well participants were informed.

Although virtually every study documented that written informed consent had been obtained, many publications omitted information such as:

• whether simplified information sheets were used
• whether participants viewed videos or digital educational materials
• whether understanding was assessed before enrolment
• whether interpreters or accessibility measures were available
• whether consent discussions continued throughout longer studies

For regulators, sponsors, and researchers, this lack of reporting limits opportunities to compare best practices and identify approaches that genuinely improve participant understanding.

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A Growing Shift Towards Participant-Centred Consent

The review also highlights an important change in thinking across clinical research.

Historically, informed consent has often been treated as a single regulatory milestone completed before enrolment.

Increasingly, however, researchers view consent as an ongoing communication process that continues throughout a participant's involvement in a trial.

Several approaches discussed in the literature include:

• electronic informed consent (eConsent)
• multimedia educational tools
• visual explanations of trial procedures
• simplified consent documents written in plain language
• interactive question-and-answer sessions
• opportunities to revisit consent during long-term studies

Although the systematic review found that these approaches were only occasionally reported in published trials, previous research has shown they can improve participant comprehension, satisfaction, and engagement.

Why Better Consent Could Improve Trial Performance

Improving informed consent is not simply an ethical objective. It may also produce operational benefits for sponsors and CROs.

Studies cited by the review suggest that participants who better understand study procedures are more likely to:

As decentralised clinical trials become more common, these benefits may become increasingly important for maintaining participant engagement throughout remote or hybrid studies

What This Means for Sponsors and CROs

For pharmaceutical sponsors and contract research organisations (CROs), informed consent is becoming more than an ethical obligation. It is increasingly recognised as a contributor to trial quality, participant experience, and operational performance.

Better-designed consent processes may help organisations:

• Improve participant understanding
• Build greater trust between participants and research teams
• Support recruitment and retention
• Reduce protocol misunderstandings
• Strengthen regulatory readiness

As decentralised clinical trials, digital health technologies, and remote participation continue to expand, sponsors are also evaluating electronic consent platforms that enable consistent information delivery while maintaining regulatory compliance.

However, the review emphasises that technology alone is unlikely to solve the problem. Clear communication remains the defining factor in successful informed consent.

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Better Consent Begins With Better Communication

Informed consent remains a cornerstone of ethical clinical research, yet the way consent is reported in published studies often fails to reflect the complexity of the process itself.

Greater transparency around consent methods, together with broader adoption of participant-centred communication strategies, could improve both research quality and participant confidence.

As clinical trials become increasingly digital and globally distributed, informed consent is likely to evolve from a regulatory requirement into a measurable indicator of trial quality.

At Pharmatica, we examine the operational, regulatory, and technological developments shaping modern clinical development. Our expert Insights help pharmaceutical leaders understand how better trial design, stronger participant engagement, and evolving clinical operations can improve both research quality and development outcomes.

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