Study spotlights disparities in COVID-19 clinical trials

Woman wearing mask in waiting room

Drazen Zigic / iStock

A study yesterday in JAMA Internal Medicine shows women and racial minorities were underrepresented in both COVID-19 clinical treatment trials and in disease prevention trials.

The research was conducted by a team from the Fred Hutchinson Cancer Center, as well researchers from Beijing and London.

"To our knowledge, this is the first study to comprehensively examine demographic representation across the landscape of both COVID-19 prevention and treatment trials over the first two years of this pandemic," said Hong Xiao, PhD, researcher in the Public Health Sciences Division at Fred Hutch and the lead author for the study, in a Fred Hutchinson press release.

The meta-analysis used data from 122 US-based COVID-19 vaccine and treatment trials, which enrolled 176,654 participants. Trials took place from October 2019 to February 2022. Studies were predominantly randomized trials (95) for the treatment of COVID-19 (103).

The analysis showed that sex, race, and ethnicity were reported in 89.3%, 77.9%, and 71.3% of US-based COVID-19 clinical trials, respectively.

This is the first study to comprehensively examine demographic representation across the landscape of both COVID-19 prevention and treatment trials over the first two years of this pandemic.

Overall, the authors said, the representation in prevention and treatment trials compared to the US population with COVID-19 was 48.9% and 44.6% vs 52.4% for female participants; 23.0% and 36.6% vs 17.7% for Hispanic or Latino participants; 7.2% and 16.5% vs 14.1% for Black participants; 3.8% and 4.6% vs 3.7% for Asian participants; 0.2% and 0.9% vs 0.2% for Native Hawaiian or Other Pacific Islander participants; and 1.3% and 1.4% vs 1.1% for American Indian or Alaska Native participants.

Hispanics only group overrepresented

Women were well-represented in COVID-19 prevention, or vaccine, trials, but underrepresented in treatment trials, with only 85% of expected participants.

The reverse was true for Black and Asian participants: Those groups were well-represented in treatment trials but underrepresented in prevention or vaccine trials—53.7% and 64.4% of expected participants, respectively.

Hispanic individuals were the only group overrepresented in treatment trials, comprising 206.8% of expected participants. The authors said one third of all US trials took place in either California, Florida, or Texas, which have large Hispanic populations. Moreover, treatment trials often enrolled hospitalized patients, and Hispanics were overrepresented as part of this group, especially during the first year of the pandemic.

In total, six trials (4.9%), all of which were prevention trials, were primarily funded by government agencies, 42 (34.4%) by industry, and 71 (58.2%) by other entities. Four trails, with more than 5,000 participants each, were large prevention trials representing 74.9% of all participants.

"Results of this systematic review and meta-analysis demonstrate that despite efforts to eliminate sex, racial, and ethnic disparities, gaps in reporting and differences in representation persisted in US-based COVID-19 trials," the authors concluded.

"In many instances, our findings highlight achievements in the successful enrollment of historically underrepresented patients," said senior author Joseph M. Unger, PhD, also of Fred Hutchinson, in the news release, as he also acknowledged the disparities. He added, "Clearly, more progress needs to occur to fully close these gaps and achieve greater diversity among participants."

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