# City Dispersion Rates

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.

## References

1. Drain PK, et al. "Global migration of clinical trials." Nat Rev Drug Discov. 2018;17:765-766.
2. Alemayehu C, et al. "Behind the mask of the African clinical trials landscape." Trials. 2018;19:519.
3. ClinicalTrials.gov API v2 Documentation. U.S. National Library of Medicine. https://clinicaltrials.gov/data-api/about-api

## Note Block

- Type: research
- App: https://mahmood726-cyber.github.io/africa-e156-students/geographic-equity/dashboards/angle-11_city-dispersion-rates.html
- Code: https://github.com/mahmood726-cyber/africa-e156-students/blob/master/geographic-equity/code/angle-11-city-dispersion-rates.py
- Data: ClinicalTrials.gov API v2
- Date: 2026-04-05