Underrecording and underreporting of participant ethnicity in clinical trials is persistent and is a threat to inclusivity and generalizability

Abstract

ObjectivesPeople from ethnic minority groups are underserved by randomized trials, and poor representation of these groups reduces generalizability of results. There is no guidance on which ethnicity categories are appropriate for use in trials and thus inconsistency exists. The purpose of this study is to establish, in a large sample of trials, if participant ethnicity is recorded, how it is obtained (categories used), and if its reporting varies from its recording. Study Design and SettingWe reviewed trial documentation for 407 randomized controlled trials published in the UK National Institute of Health Research library from 2016 to 2021. We extracted data on the recording (if it was recorded and the categories used) and reporting (if the categories remained the same as those obtained, or not) of ethnicity for each trial along with demographics. In the analysis we categorized the manner of recording and reporting of ethnicity in the trials according to UK Census ethnicity categories. ResultsEthnicity was recorded in 67.3% (n = 274) of trials. The location in the trial report where ethnicity was recorded was available for 42% (n = 116) of trials. The details on how ethnicity was collected (predefined categories or self-defined) was available for 54/274 (20%) of trials and details on the specifics of the categories recorded was available for 44 (16%) trials. Of the 44, 6 of those did not go on to report on ethnicity in the trial report. Of the remaining 38, only 13 reported ethnicity exactly as it had been recorded. Taken as a whole from the 407 trial reports examined 9.3% (38/407) of trials demonstrated exactly how they both recorded, and reported, ethnicity. Authors made reference to whom results were relevant in terms of ethnicity in 80/407 (19.7%). ConclusionEthnicity is underrecorded and underreported in clinical trials. This is a threat to the generalizability of the findings and needs to be improved.