In recent decades, the demographic structure of the world has changed dramatically: people are living longer, but not necessarily healthier. According to the World Health Organization, by 2030, one in six people globally will be over the age of 60, and by 2050, the number of people aged 60 and older will double, surpassing 2.1 billion. This is no longer an isolated phenomenon—it is a global transformation that impacts every level of the healthcare system, including clinical research.
This reality raises a fundamental question: are clinical trials truly prepared to meet the needs of an aging population?
Traditionally, older adults have been either underrepresented or outright excluded from biomedical research, resulting in less relevant treatments, inadequately designed protocols, and outcomes that are difficult to generalize. Millions of older adults—the very individuals who use most of today’s therapies—continue to be systematically excluded from the very trials that define their care. This discrepancy is not just an ethical issue; it is a major scientific vulnerability, undermining both evidence quality and clinical applicability. In an era where personalized medicine is becoming the standard, the systematic exclusion of such a critical demographic segment is no longer acceptable—scientifically or ethically.
This article explores four key dimensions of how population aging affects clinical research: the challenges of recruitment and retention, the need to adapt study design, the importance of meaningful involvement of older adults, and the strategic directions necessary to ensure research remains relevant, ethical, and effective. The clinical trials of the future cannot afford to ignore the demographic reality of the present—and today, more than ever, the typical patient is an older adult.
1. Recruitment and Retention of Older Adults: Between Real Barriers and Tested Solutions
One of the greatest inconsistencies in modern biomedical research is the absence of those who are most affected: older adults. Although they represent the demographic with the highest use of medical services and pharmaceutical therapies, they continue to be underrepresented in most clinical trials. The cause is not a lack of interest, but a combination of operational, psychosocial, and methodological barriers — some visible, others more subtle, yet highly impactful on both recruitment and retention.
Beyond multiple comorbidities and biological frailty, older adults often face logistical difficulties (such as challenges traveling to study sites), cognitive limitations (like mild memory impairment), and discomfort with complex technologies or documentation. For many, even the informed consent process can be an obstacle. Moreover, rigid eligibility criteria — often designed to minimize risk and preserve statistical homogeneity — end up excluding patients precisely for the reasons that make them relevant in real-world clinical practice: polypharmacy, chronic diseases, or complex medical histories.
These barriers are not theoretical. Studies show that older adults are frequently excluded not due to well-justified clinical contraindications, but for logistical, structural, or perceptual reasons. Even more concerning, once enrolled, older participants are at greater risk of dropping out if their interactions with the research team feel unpredictable, if they don’t feel understood, or if they encounter unresolved challenges while engaging with study procedures.
However, this reality is not irreversible. A 2024 article published in The Journals of Gerontology: Series A presents a set of practical, evidence-based strategies already validated in multicenter trials that can significantly improve both recruitment and retention of older patients:
Ultimately, including older adults in clinical research is not just a demographic imperative — it is an operational choice that requires adaptability, empathy, and long-term strategic vision. Centers that implement these strategies are not only fulfilling a social responsibility; they are demonstrating a deep understanding of what modern clinical research truly demands: reflecting the real-world clinical population as accurately as possible.
2. Adapting Study Design: Principles for Relevance, Inclusion, and Scientific Validity
In the past, excluding older adults from clinical trials was rarely questioned. Today, such exclusion is increasingly difficult to justify — both scientifically and ethically. Meaningful research must reflect the population that will ultimately benefit from its results, and in many therapeutic areas — from oncology and cardiology to neurodegenerative diseases — that population is overwhelmingly composed of older adults.
Despite this, the design of many clinical protocols remains poorly suited to the effective and safe inclusion of this patient group. Eligibility criteria are often overly restrictive, data collection methods are unnecessarily burdensome, and trial endpoints frequently ignore the functional and clinical realities of older individuals.
For clinical trials to generate evidence that is truly applicable in today's demographic context, research design must be restructured around the older patient. It is no longer enough to simply "accept" them — we must understand them, adapt trials to their needs, and define clinical validity through the lens of age-specific realities.
This transformation relies on several key principles, already validated in practice, that can turn the inclusion of older adults from exception into standard:
Adapting trial design does not mean lowering scientific standards — it means maturing them. It is a shift from the ideal of the "standardized" patient to the reality of the "representative" patient. In tomorrow’s clinical research, trials that fail to reflect this reality risk becoming irrelevant.
3. Meaningful Engagement of Older Adults: From Passive Participation to Active Co-Creation
Modern clinical trials can no longer treat older adults as a "special" or difficult category. They must be integrated as active partners in every phase of research. In an era defined by personalized medicine and increased longevity, merely including older adults in samples is no longer enough. What matters is how they are heard, understood, and integrated into the trial design.
The report published by the National Academies of Sciences, Engineering, and Medicine (NASEM), available through the NIH’s NCBI Bookshelf, emphasizes that the lack of early-stage involvement of older adults in clinical research reduces the relevance and real-world applicability of study results. Critical decisions — from eligibility criteria to visit frequency — are often made without input from those who are directly affected by them.
To address this imbalance, the report outlines a strategic approach based on three key pillars:
🔹 1. Understanding real-world barriers – Trials must start by recognizing the lived experiences of older adults: fears, functional limitations, transportation issues, the role of caregivers, or cognitive decline due to chronic illness. Without operationalized empathy, trial designs remain inaccessible and poorly suited to their needs.
🔹 2. Actively involving older adults in study design – Older adult representatives can offer valuable input into protocols: visit schedules, communication channels, preferences around telemedicine, and adaptations of digital forms. This co-creation not only enhances participant experience but also improves retention and data quality.
🔹 3. Leveraging community networks – Participation becomes more natural when supported by environments that older adults trust: senior centers, community organizations, or geriatric clinics. These networks act as trusted bridges between researchers and participants, facilitating not just recruitment but also sustained communication throughout the trial.
Rather than assuming that older adults are uninterested or incapable of participating, clinical trials must build environments that invite, support, and respect them. It's not enough to open the door — the room must be designed with them, not just for them.
4. Strategic Directions for Research in the Age of Longevity
The demographic reality of the 21st century is not merely a statistical backdrop — it is a paradigm shift that compels clinical research to fundamentally rethink its foundations. We can no longer speak of “representative” studies if they systematically exclude the very population most affected by the diseases under investigation. For science to remain relevant and applicable, a profound strategic transformation is required — one that merges methodological rigor with clinical realism.
Today’s clinical trial eligibility system continues to operate on criteria that, in practice, marginalize a large portion of older patients. As highlighted in the 2024 systematic review published in The Journals of Gerontology, multimorbidity — the coexistence of two or more chronic conditions — is the main reason for excluding older adults from biomedical studies, despite the fact that this very group consumes the most healthcare resources.
This disconnect between research and clinical reality undermines not only the ethics of trials, but also their scientific validity.
To address these challenges, four strategic directions are emerging — already validated in several international initiatives:
In the United States, the National Institute on Aging (NIA) actively supports the inclusion of individuals of all ages in biomedical research, in line with the NIH’s Inclusion Across the Lifespan policy. This initiative provides guidance and resources to help researchers adapt study protocols to the specific needs of older adults, promoting research that is both more representative and more clinically applicable.
These are not minor procedural adjustments — they represent a reconstruction of the research logic itself. A logic in which the older patient is no longer seen as a “problematic category,” but rather as an essential source of data for medical innovation.
In the age of longevity, research that ignores the realities of this population risks becoming obsolete — both clinically and strategically.
Population aging is no longer a future trend — it is the present we live in, and one to which medical research must urgently adapt. A clinical trial that ignores the demographic reality of age is not just incomplete — it is potentially irrelevant. In a healthcare system where the typical patient is increasingly an older adult, studies that continue to operate based on models built for young, healthy individuals risk providing the wrong answers to poorly framed questions.
We are living in the era of longevity — a time when life expectancy is rising steadily, fueled by advances in medicine, biotechnology, and preventive care. As treatments become more sophisticated and digitalization opens new frontiers in research, it becomes unacceptable for those who stand to benefit the most from innovation to be systematically excluded from the very studies that define their future.
This analysis highlights an issue deeper than recruitment or eligibility: it is about scientific validity, ethics, and sustainability.
Without a strategic adaptation of study design, without the active involvement of older adults, and without a profound shift in how we approach eligibility, medical research risks losing its relevance — precisely for those who need it most.
The future doesn't belong to perfect studies in the lab. It belongs to those that work in real life.
And real life is 70, 80, sometimes 90 years old.
It is polymedicated. Frail.
But worthy of high-quality science.
