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Concise consent forms are effectively understood by clinical trial participants

Shortening standard consent forms did not affect comprehension; timing and mode of delivery mattered more

Peer-Reviewed Publication


Shortening consent documents makes no significant difference to how well potential research participants understand a clinical study, according to a study published April 26, 2017, in the open-access journal PLOS ONE by Christine Grady from the NIH Clinical Center, US, and colleagues.

Informed consent is a central tenet of ethical clinical research, but over time the documents used to obtain informed consent from participants have grown longer, more complex, and harder to read. Grady and colleagues developed a "concise" alternative to consent documents used in the multinational START trial, which was shorter by almost 70 percent at 1,821 words. The new document also contained bullet points and tables, and had a simpler reading level. The authors tested these documents with 4,229 HIV-positive participants at 77 sites across the world seeking enrollment in the START trial between 2009 and 2013. The sites were randomly allocated to either the concise or the standard consent documents for participants to review.

Participants who reviewed the concise version showed no significant difference in their comprehension, satisfaction, or willingness to volunteer compared to participants who reviewed the standard form. However, comprehension was better when sites mailed the consent forms in advance and when site leaders explained the study to participants in person. One potential advantage of shorter, more concise consent forms, is that they could be reviewed more quick by an ethics committee. This could allow site leaders more time to discuss the important points of the study with their patients before enrollment in the trial, but this theory needs testing.

Whilst the study only examined one type of concise document in the context of a single clinical trial, the authors state that it is the largest test to date of modified clinical research consent forms among patients in a real clinical trial setting. They note that their results support continued efforts to make consent forms more efficient.


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Citation: Grady C, Touloumi G, Walker AS, Smolskis M, Sharma S, Babiker AG, et al. (2017) A randomized trial comparing concise and standard consent forms in the START trial. PLoS ONE 12(4): e0172607. doi:10.1371/journal.pone.0172607

Funding: This study was funded through National Institutes of Health (NIH) and National Institute of Allergy and Infectious Diseases (NIAID) Grants UM1-AI068641 and UM1-AI120197, as well as the NIH intramural program through the Clinical Center. The funder of this substudy, the US National Institutes of Health (NIH), provided support in the form of salaries for some authors [CG, MS], and grant support for some authors [AB, SS, ASW] but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of all authors are articulated in the 'author contributions' section. Genentech Research and Early Development had no role in this study.

Competing Interests: I have read the journal's policy and the authors of this manuscript have the following competing interests: CG, FH, JT, ED, NP, AP, AS, GT, MS declare no competing interests. AB, SS, SW report receipt of grants. EE reports stock ownership, paid consultancies, Board memberships, and speaking honoraria. There are no commercial or other interests that alter our adherence to PLOS One policies on sharing data and materials.

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