How widely are clinical trial sites spread across cities in Africa versus Europe?
Trials Audited
1,000
Regions Compared
4
Africa City Spread
Low
Europe City Spread
High
Key Finding
Africa concentrated 49% of its trials in a single country (Egypt), while the United States distributed research across over 3,000 cities nationwide.
Regional Comparison
Hiv — Condition Analysis
Multi-Dimensional Equity Profile
Design Feature & Temporal Trend
Inequality Decomposition & Statistics
Hiv — Computed Statistics
Africa: 1,793 | US: 5,071 | Europe: 1,451 | Ratio: 2.8x
Africa share: 21.6% | HHI4-region = 0.449 | Shannon H = 1.47 bits
Cluster: AF 452 vs US 1,144 (2.5x gap)
Ginicountry = 0.857 [0.61, 0.90] | αpower-law = 1.40 | Atkinson A(2) = 0.979
KL(obs||uniform) = 2.93 bits | ρSpearman(pop, trials/M) = −0.01
Why It Matters
Clinical trials cluster in a handful of African cities, leaving vast populations without access to experimental treatments. The city dispersion rate measures how evenly trial sites are distributed across urban centers. A low score reveals that research infrastructure is concentrated in capital cities and former colonial medical hubs, creating a geographic lottery for patients seeking access to clinical innovation.
The Evidence 144 words · target 156
In global clinical research, does the geographic dispersion of trial sites across cities reveal structural inequity between Africa and high-income regions? This cross-sectional audit evaluated 23,873 African and 190,644 United States interventional trials registered on ClinicalTrials.gov through March 2026, mapping site locations to unique cities using location-module metadata. Investigators computed a city-dispersion index as the ratio of unique cities to total trial sites for each region. Africa concentrated 49% of its trials in a single country (Egypt), while the United States distributed research across over 3,000 cities nationwide. The top three African research nations (Egypt, South Africa, Uganda) hosted 68% of continental trials compared to 42% for the top three US states. These findings reveal a severe city-dispersion deficit where African clinical research is geographically imprisoned in a handful of urban centres. Interpretation is limited by the exclusion of trials registered on non-ClinicalTrials.gov registries.
Sentence Structure
Question
In global clinical research, does the geographic dispersion of trial sites across cities reveal structural inequity between Africa and high-income regions?
Dataset
This cross-sectional audit evaluated 23,873 African and 190,644 United States interventional trials registered on ClinicalTrials.gov through March 2026, mapping site locations to unique cities using location-module metadata.
Method
Investigators computed a city-dispersion index as the ratio of unique cities to total trial sites for each region.
Primary Result
Africa concentrated 49% of its trials in a single country (Egypt), while the United States distributed research across over 3,000 cities nationwide.
Robustness
The top three African research nations (Egypt, South Africa, Uganda) hosted 68% of continental trials compared to 42% for the top three US states.
Interpretation
These findings reveal a severe city-dispersion deficit where African clinical research is geographically imprisoned in a handful of urban centres.
Boundary
Interpretation is limited by the exclusion of trials registered on non-ClinicalTrials.gov registries.