Source: The Conversation – in French– By Bamba Gaye, MD, MPH, MSc, PhD, Executive Director, Alliance for Medical Research in Africa (AMedRA) | Adjunct Professor at Biomedical Informatics, Emory School of Medicine in Atlanta, Georgia, USA |, Cheikh Anta Diop University of Dakar
Modern medicine prides itself on being a universal science, based on data from clinical trials.
But there is a bias in medical research. While Africarepresentsabout 25% of the world’s disease burden and19% of the world’s populationYet, its population is largely absent from clinical trials.
The extent of this exclusion is revealed by aflagship studycovering 2,472 randomized controlled trials published worldwide between 2019 and 2024.
I led this team of researchers, who scrutinized the world’s most influential medical publications in order to quantify African representation. Among them were the New England Journal of Medicine, The Lancet, the Journal of the American Medical Association, Nature Medicine, and the British Medical Journal. The study also covered three leading cardiology journals: Circulation, the European Heart Journal, and the Journal of the American College of Cardiology.
I am a physician-researcher and work at the intersection of cardiometabolic epidemiology and biomedical data science. I am also dedicated to large-scale population studies in Africa and data-driven cardiovascular prevention.
Randomized clinical trials are the cornerstone of evidence-based medicine. Introduced in the mid-20th century, they rigorously assess the safety and efficacy of treatments by randomly allocating participants to different groups. This method aims to minimize bias. Such trials have played a central role in major medical advances, from cardiovascular therapies to vaccines. They continue to guide clinical decisions and the development of new treatments worldwide.
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What we discovered
Our results reveal a deep imbalance in the global landscape of clinical research. Among the five most prestigious medical journals in the world, only 3.9% of the trials were conducted exclusively in Africa. In terms of cardiovascular health, these figures fall to a statistically insignificant level. Among the major trials published in leading cardiology journals, only two studies (0.6%) were conducted solely on African soil.
It is a problem of scientific reliability. When clinical trials exclude African populations, they produce data that lack “external validity.” This refers to the ability of study results to be generalized beyond the participants. The question is whether the conclusions of a clinical trial will remain valid when applied to different populations, contexts, or real-world conditions.
Without this validity, doctors apply uncertain results to millions of patients every day.
Modern medicine cannot claim to be universal if entire populations remain invisible in the evidence base. Biology, health systems, and epidemiological patterns are not the same everywhere in the world.
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The ditch and its importance
Many treatments used on the continent are based on data generated from non-African populations, which raises concerns about their applicability.
Furthermore, most of the trials conducted in Africa still focus on infectious diseases, despite the growing burden of non-communicable diseases such as cardiovascular diseases.
New datashowthat genetics, environment, and diet can radically change how an organism reacts to a drug. It is therefore not logical, from a medical point of view, that an entire continent be excluded from the clinical trial network.
There is also evidenceshowingthat some treatments have different safety profiles in black patients. Diabetes and gout are just two examples. The same applies to certain common medications for hypertension, such asangiotensin-converting enzyme (ACE) inhibitors. Researchshowthat they present a risk three to four times higher of serious and potentially fatal side effects in people of African origin compared to other populations.
When clinical trials exclude certain populations, doctors are forced to extrapolate the results obtained on one population and apply them to another.
The study also highlights a dangerous gap between global research funding and the evolution of health realities in Africa. New data show that nearly 76% of trials conducted exclusively in Africa focused on infectious diseases. However, the continent is currently undergoing a major epidemiological transition. Non-communicable diseases – heart diseases, strokes, and diabetes – now represent approximately38% of all deathsin many African countries.
The middle class in Africa hastripledto reach 300 million people, compared to about 100 million at the beginning of the 2000s. More and more people are now living long enough with lifestyles that increase the risk of chronic diseases such as heart disease, diabetes, and hypertension. Consequently, there is a growing need and market for long-term treatments to manage these diseases, rather than for short-term therapies against infections. However, cardiovascular trials continue to be discouraged.
Even within the continent, the data reveal real blind spots in terms of information. South Africa accounts for more than 62% of all trials conducted on the continent. Central Africa, a region with more than 180 million inhabitants, was practically absent from global research registers. It contributed to less than 3% of the continent’s limited clinical trial output.
Among the possible reasons are the decades of accumulated investments by South Africa, which result in stronger university hubs, better research governance, experienced trial units, and more established relationships with sponsors. Other regions face obstacles such as research institutions with fewer resources, more limited access to clinical trial platforms, and sometimes language and publication issues that can reduce their visibility in leading journals.
This inequality extends to the scientific hierarchy itself. Even when African sites are included in large multi-continental clinical trials, they are often relegated to the role of “recruitment centers” rather than that of scientific partners.
Our study revealed that African scientists led only 3.6% of the trials across multiple continents including an African site.
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Towards a new era for African science
Africa should not be content to be merely a place where studies are conducted.
It must be a place where research is conceived, directed, and interpreted. The current model creates a cycle of dependence on the outside, in which international institutions manage funding and data. This makes local research systems fragile and unable to translate evidence into national policies.
It is necessary to establish “reserved” funding for research led by Africans, to develop regional clinical trial networks, and to require medical journals to report on the diversity of populations participating in trials.
There are signs indicating a growing dynamic. Organizations such asThe Alliance for Medical Research in Africaare striving to train a new generation of African researchers. Africa must create a research ecosystem too important for the international community to ignore.
Bamba Gaye, MD, MPH, MSc, PhD does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
–ref. Bias in medical research: Africa absent from clinical trials –https://theconversation.com/medical-research-bias-africa-absent-from-clinical-trials-282184