Length and complexity of US and international HIV consent forms from federal HIV network trials

Informed consent is required in most clinical research with humans. While federal regulations state consent information should be understandable to participants, concerns have been raised that consent forms are overly long and complex.

Consent forms from 2006 HIV network trials sponsored by the National Institutes of Health (NIH), Division of AIDS (DAIDS), were analyzed for complexity and length. Comparisons were made between US and international sites, template and site forms, adult and pediatric trials, and trial type. How randomization and placebos were explained was examined as these are frequently misunderstood.

One hundred twenty-four consent forms (21 template and 103 site forms) were reviewed. Median readability was 9.2 grade level, although confidentiality sections were 12.35 median grade level. International sites' forms had lower readability than US forms (p = 0.025), template forms had lower readability than site forms (p = 0.046), and adult forms were less complex than pediatric (parent) forms (p < 0.0001). Median length of all forms was 22.4 pages; the 85 forms from adult studies had a median length of 27.4 pages. Sections describing randomization were a median length of 53 words.

Consent forms are extremely long, exceeding recommendations for how much information readily can be processed. Networks should consider providing shorter consent templates, consistent with federal recommendations, given that sites' forms are based on these models. Further research should examine whether forms emphasizing key information (rather than providing details about all aspects of the research) improve understanding of research.