Highlights
- Between 2019 and 2024, only 3.9% of RCTs in top general medical journals were conducted exclusively in Africa.
- The representation in leading cardiovascular journals is even lower, with just 0.6% of trials being Africa-only.
- Africa-based trials are heavily skewed toward infectious diseases (75.9%), despite the rising burden of non-communicable diseases (NCDs).
- South Africa dominates the African research landscape, while Central African nations remain almost entirely excluded from high-impact clinical evidence production.
- Equitable leadership remains a challenge; African researchers are frequently leads in local trials but are underrepresented in multicontinental trial leadership.
Background
The paradigm of evidence-based medicine (EBM) relies on the premise that clinical guidelines are informed by high-quality data from randomized controlled trials (RCTs). However, for these findings to be truly universal, the populations studied must reflect the diversity of the global population. Africa represents approximately 17% of the global population and bears a disproportionately high share of the global disease burden. This includes a persisting struggle with infectious diseases alongside an accelerating epidemic of non-communicable diseases (NCDs), particularly cardiovascular disease (CVD), hypertension, and diabetes.
Despite this clinical reality, the “evidence gap” between high-income countries (HICs) and low-to-middle-income countries (LMICs) in Africa remains a significant barrier to health equity. When clinical trials are conducted predominantly in Western populations, the results may not be directly generalizable to African cohorts due to differences in genetic diversity, environmental factors, social determinants of health, and health system infrastructure. This review synthesizes recent data regarding African representation in the world’s most influential medical and cardiovascular journals, highlighting the urgent need for a more inclusive research ecosystem.
Key Content
Methodological Overview of the Systematic Review (2019–2024)
The primary data analyzed in this synthesis originates from a systematic review (Gaye et al., 2024) that scrutinized RCTs published between January 2019 and June 2024. The study focused on two clusters of elite publications:
- General Medical Journals: The New England Journal of Medicine (NEJM), The Lancet, JAMA, British Medical Journal (BMJ), and Nature Medicine.
- Cardiovascular Journals: Circulation, European Heart Journal (EHJ), and Journal of the American College of Cardiology (JACC).
The researchers assessed 2,472 RCTs in total, categorizing them by trial scope (Africa-only vs. multicontinental), regional participation (Northern, Western, Central, Eastern, and Southern Africa), disease focus, and authorship metrics.
The Magnitude of Underrepresentation
The findings reveal a staggering disparity in research output. Out of 2,138 RCTs published in the leading general medical journals, only 83 (3.9%) were conducted exclusively in African countries. An additional 195 (9.1%) were multicontinental trials that included at least one African site. While these numbers are low, the situation in cardiovascular medicine is markedly more severe.
In the three leading CV journals, only 2 out of 334 RCTs (0.6%) were Africa-only. Furthermore, African sites were included in only 2.7% of multicontinental cardiovascular trials. This suggests that the evidence base used to treat heart failure, coronary artery disease, and arrhythmias in African patients is almost entirely derived from non-African populations. This “cardiovascular void” is particularly concerning given that hypertension and stroke are leading causes of morbidity across the continent.
Regional Disparities and the “South African Hegemony”
Within the limited volume of African research, there is a profound lack of geographic balance. South Africa accounted for the vast majority of trial sites in both general and cardiovascular categories. Southern Africa as a region dominated the data, while Central Africa was almost entirely unrepresented in high-impact publications during the study period. This regional imbalance means that even within the “African representation” metric, the specific health needs and genetic contexts of hundreds of millions of people in Central and Western Africa are still being overlooked.
Disease Categorization: The Infectious Disease Bias
A critical finding of the 2019–2024 review is the divergence in disease focus. Trials conducted exclusively in Africa and published in general journals were overwhelmingly focused on infectious diseases, such as HIV/AIDS, tuberculosis, and malaria (75.9% of trials). In contrast, only 3.6% of Africa-only trials in these journals addressed cardiovascular disease.
Interestingly, when African sites were part of multicontinental trials, the focus shifted toward NCDs. This indicates that while global research networks are beginning to include Africa in NCD research, local, African-led initiatives published in top-tier journals are still predominantly funded and structured around infectious disease priorities. This mismatch between local research focus and the shifting epidemiological reality of the continent (the “epidemiologic transition”) highlights a lag in research funding and infrastructure.
Authorship and Research Leadership
Representation is not just about where the patients are located, but also who leads the science. The review found that in Africa-only trials, African researchers frequently held senior authorship positions (first or last author). However, in multicontinental trials—which are often larger and more influential—African authorship was significantly lower. This suggests a pattern of “extractive research” or “helicopter science,” where African sites provide data and patients, but the intellectual leadership and primary recognition remain centered in HICs.
Expert Commentary
The findings from the 2019–2024 period present a dual challenge: one of scientific validity and one of ethical equity. From a mechanistic perspective, the lack of African representation in clinical trials is a major scientific limitation. African populations harbor more genetic diversity than any other global population. For example, pharmacogenomic variations in the metabolism of drugs like warfarin or certain antihypertensives mean that dosing strategies developed in Europe may be suboptimal or even unsafe in African contexts.
Furthermore, the infrastructure for RCTs—including clinical trial units, regulatory oversight, and laboratory capacity—is an essential component of a robust healthcare system. By excluding African sites from major trials, the global community misses an opportunity to build local capacity. Experts argue that the barriers to inclusion are often perceived rather than actual; concerns about “loss to follow-up” or “infrastructure gaps” are frequently mitigated by the high level of participant engagement and the rapid development of research excellence in hubs like Nairobi, Cape Town, and Lagos.
There is also the issue of “journal gatekeeping.” High-impact journals tend to prioritize trials that have large sample sizes and immediate implications for the HIC markets where their primary readers reside. This creates a circular logic where African trials are not published because they are “too local,” yet they remain local because there is no global incentive or funding to scale them.
Conclusion
The systematic review of literature from 2019 to 2024 confirms that African countries remain on the periphery of high-impact clinical research, particularly in the realm of cardiovascular medicine. While there is a strong foundation in infectious disease research, the evidence base for treating non-communicable diseases in African populations is critically thin.
To move forward, the global medical community must prioritize three actions:
- Funding Diversification: International funding bodies must pivot to support NCD research within Africa, moving beyond the traditional silos of infectious disease.
- Equitable Partnerships: Multicontinental trials should mandate the inclusion of local investigators in leadership roles and ensure that the research questions asked are relevant to the host community.
- Infrastructure Investment: Investing in clinical trial networks across Central and Western Africa is necessary to break the regional concentration of research in the South.
Addressing these disparities is not merely a matter of social justice; it is a requirement for the scientific integrity of global health. Only through inclusive representation can we ensure that the next five years of medical breakthroughs are truly applicable to all of humanity.
References
- Gaye B, Morsy MI, Kitara DL, et al. African Representation in Randomized Controlled Trials Published in Leading Medical and Cardiovascular Journals, 2019-2024. J Am Coll Cardiol. 2026;41860521. PMID: 41860521.
- Owolabi MO, et al. The shifting burden of cardiovascular disease in sub-Saharan Africa. Nature Reviews Cardiology. 2022;19(11):747-770.
- Kengne AP, et al. Cardiovascular diseases in Africa: epidemiological profile and challenges. The Lancet. 2023;401(10385):1345-1358.
