Improving assent in health research: a rapid systematic review

Background: Enrolment in a research study requires the participant's informed consent. In the case of minors, informed consent of the respective legal guardian is obtained in conjunction with informed assent of the underage p articipant. Since comprehension of the information provided may be limited, effective interventions to improve understanding should be identified. Thus, it is the objective of this study to review quantitative studies that tested interventions to improve the understanding of information provided during assent processes in health research. The studied population consisted of minors that participated or were willing to participate in research. The primary outcome was the level of comprehension after intervention. 

Methods: A systematic search was conducted in eleven databases including regional databases: PubMed, Web of Science, ERIC, PsycINFO, CINAHL, POPLINE, AIM, LILACS, WPRIM, IMSEAR, and IMEMR and included references from inception of the database until July 2018 except PubMed which spanned the period from May 2013 to July 2018. Search terms focused on Informed Consent/Assent, Minors, and Comprehension. To complement the search, reference lists of retrieved publications were additionally searched. We included all quantitative studies that were conducted in minors, tested an intervention, covered assent processes in health research, and assessed comprehension. One reviewer screened titles, abstracts, and full-texts to determine eligibility and collected data on study design, population, intervention, methods, outcome, and for critical appraisal. Interventions comprised enhanced paper forms, interspersed questions, multimedia format, and others. 

Results: Out of 7089 studies initially identified, 19 studies comprising 2805 participants and conducted in seven countries were included in the review. Fourteen studies (74 %) tested an intervention against control and ten (53 %) were randomized controlled trials. Heterogeneous methodology as well as incomplete outcome and statistical reporting impaired the reliability of the collected data. Positive effects were suggested for use of enhanced paper forms, interspersed questions, use of pie charts, and organizational factors. 

Conclusions: Improving assent in health research is an under-researched area with little reliable evidence. While some interventions are proposed to improve understanding in assent processes, further investigation is necessary to be able to give evidence-based recommendations. Trial registration: PROSPERO ID: 106808.