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      Improving understanding in the research informed consent process: a systematic review of 54 interventions tested in randomized control trials


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          Obtaining informed consent is a cornerstone of biomedical research, yet participants comprehension of presented information is often low. The most effective interventions to improve understanding rates have not been identified.


          To systematically analyze the random controlled trials testing interventions to research informed consent process. The primary outcome of interest was quantitative rates of participant understanding; secondary outcomes were rates of information retention, satisfaction, and accrual. Interventional categories included multimedia, enhanced consent documents, extended discussions, test/feedback quizzes, and miscellaneous methods.


          The search spanned from database inception through September 2010. It was run on Ovid MEDLINE, Ovid EMBASE, Ovid CINAHL, Ovid PsycInfo and Cochrane CENTRAL, ISI Web of Science and Scopus. Five reviewers working independently and in duplicate screened full abstract text to determine eligibility. We included only RCTs. 39 out of 1523 articles fulfilled review criteria (2.6%), with a total of 54 interventions. A data extraction form was created in Distiller, an online reference management system, through an iterative process. One author collected data on study design, population, demographics, intervention, and analytical technique.


          Meta-analysis was possible on 22 interventions: multimedia, enhanced form, and extended discussion categories; all 54 interventions were assessed by review. Meta-analysis of multimedia approaches was associated with a non-significant increase in understanding scores (SMD 0.30, 95% CI, -0.23 to 0.84); enhanced consent form, with significant increase (SMD 1.73, 95% CI, 0.99 to 2.47); and extended discussion, with significant increase (SMD 0.53, 95% CI, 0.21 to 0.84). By review, 31% of multimedia interventions showed significant improvement in understanding; 41% for enhanced consent form; 50% for extended discussion; 33% for test/feedback; and 29% for miscellaneous.Multiple sources of variation existed between included studies: control processes, the presence of a human proctor, real vs. simulated protocol, and assessment formats.


          Enhanced consent forms and extended discussions were most effective in improving participant understanding. Interventions of all categories had no negative impact on participant satisfaction or study accrual. Identification of best practices for studies of informed consent interventions would aid future systematic comparisons.

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          Interventions to improve research participants' understanding in informed consent for research: a systematic review.

          Available data suggest that prospective research participants may frequently not understand information disclosed to them in the informed consent process. Little is known about how understanding can be improved. To review research on interventions to improve research participants' understanding of information disclosed in the informed consent process. A search of MEDLINE was performed using the terms informed consent and clinical research and informed consent and (comprehension or understanding) from 1966 to March 2004 , which included randomized controlled trials, longitudinal trials, and controlled trials with nonrandom allocation that compared the understanding of research participants who had undergone only a standard informed consent process to that of participants who had received an intervention to improve their understanding. A comprehensive bibliography of empirical research on informed consent published in January 1999 was also reviewed, as were personal files and all issues of the journals IRB and Controlled Clinical Trials. Study design, quality criteria, population characteristics, interventions, and outcomes for each trial were extracted. The statistical significance of the interventions' effects on understanding were noted, as were mean scores for understanding for each group of each trial. For those trials that measured the secondary outcomes of satisfaction and willingness to enroll, results were also summarized. Thirty studies described 42 trials that met inclusion criteria. Of 12 trials of multimedia interventions, 3 showed significant improvement in understanding. Of 15 trials of enhanced consent forms, 6 showed significant improvement in understanding (all P<.05), but 5 of 6 trials were of limited quality, casting doubt on their practical relevance. Of 5 trials of extended discussion, 3 showed significant improvement in understanding (all P<.001) and 2 showed trends toward improvement (P=.054 and P=.08). Of 5 trials of test/feedback, all showed significant improvement in understanding (all P<.05) but were flawed in that they may have mistaken rote memorization for improvement in understanding. Another 5 trials were put into a miscellaneous category and had varying impact on understanding. Some demographic factors, particularly lower education, were associated with less understanding. Satisfaction and willingness to enroll were never significantly diminished by an intervention . Efforts to improve understanding through the use of multimedia and enhanced consent forms have had only limited success. Having a study team member or a neutral educator spend more time talking one-on-one to study participants appears to be the most effective available way of improving research participants' understanding; however, further research is needed.
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            Informed consent: how much and what do patients understand?

            We sought to evaluate the degree of patients' understanding of several aspects of the informed consent process for surgery and clinical research. We conducted a systematic search of PubMed (1961-2006) to identify relevant articles. We retrieved 23 and 30 eligible for inclusion articles regarding informed consent for surgery and clinical research, respectively. Regarding surgery, adequate overall understanding of the information provided and of the risks associated with surgery was shown in 6 of 21 (29%) and 5 of 14 (36%) studies providing relevant data, respectively. Regarding clinical research, adequate understanding of the aim of the study, the process of randomization, voluntarism, withdrawal, and the risks and the benefits of treatment was shown in 14 of 26 (54%), 4 of 8 (50%), 7 of 15 (47%), 7 of 16 (44%), 8 of 16 (50%), and 4 of 7 (57%) of studies providing relevant data, respectively. Satisfaction by the amount of the given information was shown in 7 of 12 (58%) studies involving surgery and 12 of 15 (80%) studies involving clinical research. Further attention should be drawn on enhancing patients' understanding regarding several components of the informed consent process for surgery and clinical research.
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              Informed consent in genomics and genetic research.

              There are several features of genetic and genomic research that challenge established norms of informed consent. In this paper, we discuss these challenges, explore specific elements of informed consent for genetic and genomic research conducted in the United States, and consider alternative consent models that have been proposed. All of these models attempt to balance the obligation to respect and protect research participants with the larger social interest in advancing beneficial research as quickly as possible.

                Author and article information

                BMC Med Ethics
                BMC Med Ethics
                BMC Medical Ethics
                BioMed Central
                23 July 2013
                : 14
                : 28
                [1 ]University of Washington, Seattle, WA, USA
                [2 ]Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
                [3 ]Department of Medicine, Mayo Clinic, Rochester, MN USA
                [4 ]Knowledge and Evaluation Research Unit, Mayo Clinic, Rochester, MN USA
                [5 ]Biomedical Ethics Research Unit, Mayo Clinic, Rochester, MN USA
                Copyright © 2013 Nishimura et al.; licensee BioMed Central Ltd.

                This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

                : 8 February 2013
                : 13 June 2013
                Research Article

                informed consent,comprehension,systematic review
                informed consent, comprehension, systematic review


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