Importance: Obtaining voluntary informed consent prior to enrollment in clinical trials is a fundamental ethical requirement.
Objective: To assess whether health literacy, contextual factors, or sociodemographic characteristics are associated with perception of voluntariness among parents who had consented for their child's participation in a leukemia therapeutic clinical trial.
Design, setting, and participants: This cross-sectional study prospectively enrolled 97 parents of children diagnosed as having leukemia at Rady Children's Hospital San Diego, a large tertiary academic center in California, from 2014 to 2017. Health literacy, contextual factors (acculturation, decisional regret, and satisfaction with informed consent), sociodemographic characteristics, and perception of voluntariness after consenting for a therapeutic clinical trial were measured. Univariable and multivariable regression were used to determine significant associations. The analyses for the present study were conducted from May 2019 to May 2020.
Exposures: Informed consent for a therapeutic leukemia clinical trial.
Main outcomes and measures: The primary outcome of interest was perception of voluntariness and its associations with health literacy and other contextual factors (acculturation, decisional regret, and satisfaction with informed consent) and sociodemographic characteristics, including age, race/ethnicity, parental language, educational level, insurance type, marital status, and socioeconomic status.
Results: Of 97 parents included, the majority were women (65 [67%]), married (71 [73%]), and of self-reported Hispanic ethnicity (50 [52%]). Lower perception of voluntariness was significantly associated with lower health literacy (r = 0.30; 95% CI, 0.11-0.47; P = .004), Spanish language (x̅ = -4.50, P = .05), lower acculturation if of Hispanic ethnicity (r = 0.30; 95% CI, 0.02-0.54; P = .05), greater decisional regret (r = -0.54; 95% CI, -0.67 to -0.38; P < .001), and lower satisfaction with informed consent (r = 0.39; 95% CI, 0.21-0.54; P < .001) in univariable analysis. Lower health literacy remained significantly associated with lower perception of voluntariness in multivariable analysis after adjustment for contextual factors and sociodemographic characteristics (β = 4.06; 95% CI, 1.60-6.53; P = .001). Lower health literacy was significantly associated with Hispanic ethnicity (mean, 4.16; 95% CI, 3.75-4.57; P < .001), Spanish language spoken at home (mean, 3.17; 95% CI, 1.94-4.40; P < .001), high school or less educational level (mean, 3.41; 95% CI, 2.83-3.99; P < .001), public insurance (mean, 4.00; 95% CI, 3.55-4.45; P < .001), and unmarried status (mean, 3.71; 95% CI, 2.91-4.51; P = .03).
Conclusions and relevance: Among parents of children with newly diagnosed leukemia who had consented for their child's participation in a therapeutic clinical trial, lower perception of voluntariness was significantly associated with lower health literacy. These results suggest that parents with low health literacy may perceive external influences in their decision for their child's participation in clinical trials. This finding highlights the potential role of recruitment interventions tailored to the participant's health literacy level to improve voluntary informed consent in underserved populations.