Understanding Income Barriers in Clinical Trial Participation is Needed to Improve Treatment, Outcomes

Patients with lower incomes are less likely to participate in clinical trials than patients with higher incomes, regardless of age, according to Joseph M. Unger, PhC, of SWOG Statistical Center. Mr. Unger presented the results of “Patterns of decision making about cancer clinical trial participation among the online cancer treatment community: A collaboration between SWOG and NexCura” (Abstract CRA6009) Sunday at the Clinical Science Symposium “Optimizing Delivery of High-Quality Cancer Care.”

Investigators drew their large national sample from patients using NexCura, a Web-based treatment decision tool. Patients older than age 18 who were recently diagnosed with breast, lung, colorectal, or prostate cancer were eligible and their reasons for not participating in a clinical trial were assessed using prespecified items regarding treatment, family, cost, and logistics.

Information about comorbidities and distance to their clinic was also collected. All data collected in the study were self-reported. Of the 5,499 evaluable patients who were surveyed between 2007 and 2011, 40% discussed clinical trial participation with their physician; of that 40%, 45% were offered participation in a clinical trial; of that 45%, 51% chose to participate in the trial, demonstrating an overall clinical trial participation rate of 9% (496 out of 5,499 patients).

The 40% of participants who did discuss clinical trials with their physician varied by age (42% younger than age 65 versus 29% older than age 65), income (42% more than $50,000/year versus 36% less than $50,000/year), and education (42% with a college degree versus 37% without).

Using a multivariate model including all socioeconomic status factors and demographic factors, investigators noted that income remains a predictor for patient participation in clinical trials.

“Specifically, patients making less than $50,000 per year are 27% less likely to participate than patients making $50,000 per year or more. The association between income and clinical trial participation was consistently strong regardless of how income was categorized,” said Mr. Unger. “For example, patients making less than $20,000 per year were 44% less likely to participate than patients making $20,000 per year or more.”

Even for patients older than age 65 who are universally covered by Medicare, lower income predicted lower participation in clinical trials. Cost concerns were much more evident among patients with lower incomes (p = 0.001), Mr. Unger noted. He stated factors such as the out-of-pocket costs of copayments and the indirect costs of time off work for extra clinic visits and transportation as potential drawbacks for these patients.

“From the patient’s perspective, since clinical trials utilize state-of-the-art treatments, this finding raises concern about whether all income groups have equal access to trials,” said Mr. Unger. “From the researcher’s perspective, greater participation by lower-income patients would speed the conduct of clinical trials and would better assure the applicability of clinical trial results to all income levels. We hope these results raise awareness about how concerns about how to pay for clinical trial participation may limit the participation of lower-income patients.”

In discussing this study, Terrance L. Albrecht, PhD, of Karmanos Cancer Institute, noted that the study quantified general variables (e.g., income, neighborhood characteristics) that identify problems in broadening the socioeconomic status levels of clinical trial participants, but more work is needed to solve them.

“We have identified the problems, but we need to drill down further to start with the patient experience,” she said. Patient understanding of conversations can vary based on literacy and comprehension errors.

Thinking about this issue from a patient-centered approach reveals the complexity of the patient decision-making process and may lead to solutions that identify potentially modifiable factors that can improve the quality of care.