Disparities in Research Participation by Level of Health Literacy

Objective: To determine at which phase in the recruitment process for participation in clinical research studies do health literacy and other patient characteristics influence recruitment outcomes.

Patients and methods: Using a sample of 5872 patients hospitalized with cardiovascular disease approached for participation in the Vanderbilt Inpatient Cohort Study from October 2011 through December 2015, we examined the independent association of patients' health literacy with two steps in their research participation decision-making process: (1) research interest - willingness to hear more about a research study; and (2) research participation - the decision to enroll after an informed consent discussion. Best practices for effective health communication were implemented in recruitment approaches and informed consent processes. Using logistic regression models, we determined patient characteristics independently associated with patients' willingness to hear about and participate in the study.

Results: In unadjusted analyses, participants with higher health literacy, and those who were younger, female, or had more education had higher levels of both research interest and research participation. Health literacy remained independently associated with both outcomes in multivariable models, after adjustment for sociodemographic factors.

Conclusion: Because identical variables predicted both research interest and eventual consent, efforts to recruit broad populations must include acceptable methods of approaching potential participants as well as explaining study materials.