Increasing financial compensation could drive more diverse clinical trial participation, study says

The problem of minority populations not being adequately represented in clinical trials has long vexed healthcare researchers, but it can be fixed by increasing the payment for such participation, according to researchers with the University of Chicago.

Their working paper (PDF) argues that offering participants $500 would entirely close the gap in participation among different socioeconomic, racial and ethnic groups. Data on participants show who isn’t included in the tests but not why that’s the case. The researchers looked at the effect of three different incentives on participation: $0, $100 and $500.

They considered six characteristics: higher poverty neighborhood, minority neighborhood, uninsured rate, preventable hospitalization rate per 10,000 individuals, drug-related hospitalization rate per 10,000 individuals and the COVID-19 local risk index from 1 to 10.

Studies without any incentives would be highly nonrepresentative, as would studies with the $100 incentive, though not as much as studies with no incentives.

“However, a study with a $500 incentive is representative on all six characteristics, with average participant characteristics that are statistically indistinguishable from those in the target population,” the study said. “For example, with no incentive, only 13% of the participants are from higher poverty neighborhoods, compared to a target population average of 46%. This figure would increase to 22% with a $100 incentive, and to 51% with a $500 incentive.”

But would paying $500 a participant be economically feasible for those institutions conducting the studies?

“This is certainly doable,” David Cutler, Ph.D., an internationally known healthcare economist, told Fierce Healthcare. “There is no obvious reason why people cannot be compensated for participation in clinical trials, and the cost would not be large relative to the total cost of clinical trials.”

Richard Stefanacci, chief medical officer at the Jefferson College of Population Health at Thomas Jefferson University, told Fierce Healthcare that a congressional push might be needed to make studies more diversified and cites legislation introduced last month in the Senate by Bob Menendez, D-New Jersey, and Susan Collins, R-Maine. Their bill calls for more diversity of participants in studies funded by the National Institutes of Health.  

Stefanacci said “studies are already incredibly costly, pushing many to reconsider the value of even undertaking such studies, which could end up decreasing the number of drugs studied.”

But a press release by the University of Chicago released with the working paper said better diversification in studies equals better healthcare for society.

“In the case described in this new research, a lack of representation from Black, Hispanic, and low socioeconomic status households poses a risk to public health and a challenge for policymakers responding to COVID-19. If we don’t know why these households don’t participate, we cannot effectively encourage greater participation and, thus, improve health outcomes," according to the release.

Researchers used data from the Representative Community Survey Project’s COVID-19 serological study. Some households in Chicago were sent a blood sample collection kit and were instructed to mail the sample to a research laboratory. The households were randomly assigned to receive a $0, $100 or $500 participation payment.

A letter in the kit “informed the household that the returned blood sample would be tested for seropositivity, but that they would not be told the result of the test,” the study said. “Hence, desire to learn about seropositivity status could not contribute to the household’s motivation for participating in the study.”

The two main reasons for individuals not participating in clinical studies are that they cannot be contacted or hesitancy. The researchers argue that poor and minority households don’t participate because they think doing so might in some way cost them money, not because they are more difficult to contact.

“For example, 61% of contacted households in majority minority neighborhoods would not participate for $100, compared to only 14% in majority White neighborhoods,” according to the University of Chicago press release. “Hesitancy explains 89% of the participation gap at $0, and 93% at $100.”

The study concluded that “randomized financial incentives can be used to measure the causes of non-participation and how they contribute to underrepresentation. In the context of the RECOVER serological study, we found that non-contact is a cause for low participation, but not of underrepresentation. Hesitancy among contacted households is a cause of both low participation and underrepresentation. High incentives for participation appear to restore representativeness.”

Stefanacci said he remains unconvinced that more compensation for study participants will solve the diversity problem.

“High financial payments for study participation may bias the study results as those paid especially these high sums would underreport adverse events, their exclusion criteria and be more positive on the outcomes,” he said.