Background: Lack of participation of black and minority ethnic communities (BAME) in registered clinical trials is a concern as data emerging from these studies are used to licence new drugs or other interventions, even though findings made in such selected study populations have limited external validity in the aforesaid ethnic groups. Objective: We used Parkinson's disease (PD), the fastest rising neurodegenerative disorder in the world, as an exemplar condition to test our hypothesis that participants from BAME communities are underrepresented in clinical trials. Methods: A systematic search of clinical trials registered on a Clinicaltrials.gov database which queried for PD with racial distribution data from 2017 to 2021. Results: Out of 266 trials considered, 54 trials were published in peer reviewed journals. Among these, only 23 (42.65%) publications reported data regarding the racial distribution of the participants. Out of these, five studies involved mixed racial participation and two trials included black subjects. Conclusion: We found that inclusion of under-represented BAME groups in recently published clinical trials is low, at only 21.57%, and is not even considered in most studies. Out of the reviewed trials, only 5 (21.75%) studies reported detailed demographic categories with black minorities enrolment. This constitutes a severe under-representation when compared to the proportion of Black or African American in the UK population (3%). Results of this study identified the need for better reporting of racial composition in clinical trials. We strongly recommend that future studies should consider ethnicity and other issues around diversity when designing and implementing the clinical trials, not only in the PD field but also beyond.

Original languageEnglish
Pages (from-to)975-981
Number of pages7
JournalJournal of Parkinson's Disease
Issue number3
Early online date21 Jan 2022
Publication statusPublished - 5 Apr 2022


  • ethnicity
  • Clinical trials
  • Parkinson’s disease
  • diversity


Dive into the research topics of 'Does Ethnicity Influence Recruitment into Clinical Trials of Parkinson's Disease?'. Together they form a unique fingerprint.

Cite this