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The effectiveness of health literacy interventions on the informed consent process of health care users: a systematic review protocol

Perrenoud, Beatrice; Velonaki, Venetia-Sofia; Bodenmann, Patrick; Ramelet, Anne-Sylvie

Author Information
JBI Database of Systematic Reviews and Implementation Reports: October 2015 - Volume 13 - Issue 10 - p 82-94
doi: 10.11124/jbisrir-2015-2304
  • Free


Inclusion criteria

Types of participants

This review will consider all studies that include adults (18 years or over) receiving care or adults who are proxies of incompetent health care users or of children (parents or guardians) who have been actively involved in an informed consent process regarding health care procedures.

Participants may be healthy or may have any kind of physical disability, be recruited in any type of health care environment, including acute (hospital), primary care, psychiatric and aged care, in any health specialty, including medicine, dentistry and pharmacy. Studies whose participants have cognitive impairment will be excluded. Studies on informed consent processes for research participants will be also excluded.

Types of intervention(s)

The interventions, methods, and strategies will be included if:

  • they aim to improve the informed consent process related to health issues among health care users or their proxies,
  • they are designed taking into consideration health literacy as a main concept, and
  • the intervention is provided by any health care provider.

Such interventions my focus on either the material provided (e.g. readability, processability), or the supportive procedure of informed consent (e.g. video) in order to decrease the health literacy level required for making an informed choice.

Types of comparators

The comparator will be any traditional or usual or standardized informed consent information procedure.

Types of outcomes

This review will consider studies that include the following outcome measures:

Assessment of decision related to informed consent (was the choice informed?), comprehension or understanding, knowledge, decisional conflict, satisfaction, recall of the information, anxiety or attitude regarding the involvement in the decision.

This review will consider studies that use any instrument, whether validated or not, to assess one or more of the above mentioned outcomes. Studies using unvalidated instruments will be not excluded because this criterion is not clearly relevant for some of the outcomes (e.g. comprehension, knowledge).

Types of studies

This review will consider any randomized controlled trials (RCT) that examine the effectiveness of interventions considering health literacy on the informed consent process for health care users. In the absence of RCTs any other quantitative designs, such as non-randomized experimental and quasi experimental, before and after studies, prospective and retrospective cohort studies, case control studies, case series/case reports and observational studies, will be considered for inclusion in a narrative summary. This review will exclude papers which describe qualitative studies, expert opinion texts, editorials and conference papers.

Search strategy

The search strategy aims to find both published and unpublished studies. A three-step search strategy will be utilized in this review. An initial limited search will be undertaken followed by an analysis of the text words contained in the title and abstract, and of the index terms used to describe the article. A second search using all identified keywords and index terms will then be undertaken across all included databases. Thirdly, the reference list of all identified reports and articles will be searched for additional studies. Studies published in English, French and Greek will be considered for inclusion in this review. No limits by publication date will be imposed on the systematic review. Search strategies for individual databases will be developed in conjunction with a research librarian.

The databases to be searched include:

Medline Ovid, CINAHL, EMBASE, PsycINFO, Cochrane Central Register of controlled Trials

The search for unpublished studies will include:

New York Academy of Medicine Grey Literature Report, Google Scholar, National Library of Medicine and National Institute of Health literature information resources

Initial keywords to be used will be:

Informed consent, informed choice, decision making (all combined with OR) AND

Health literacy, information literacy, numeracy, readability, comprehension, understanding (all combined with OR)

Assessment of methodological quality

Papers selected for retrieval will be assessed by two independent reviewers for methodological validity prior to inclusion in the review using standardized critical appraisal instruments from the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI) (Appendix I). Any disagreements that arise between the reviewers will be resolved through discussion, or with a third reviewer.

Data extraction

Data will be extracted from papers included in the review using the standardized data extraction tool from JBI-MAStARI (Appendix II). The data extracted will include specific details about the interventions, populations, study methods and outcomes of significance to the review question and specific objectives. Where reported data are unclear or aggregated, the authors of primary studies will be contacted with requests to provide disaggregated data.

Data synthesis

Quantitative data will, where possible, be pooled in statistical meta-analysis using JBI-MAStARI. All results will be subject to double data entry. Effect sizes expressed as odds ratio (for categorical data) and weighted mean differences (for continuous data) and their 95% confidence intervals will be calculated for analysis. A random effects model will be used and heterogeneity will be assessed statistically using the standard Chi-square. If possible, subgroup analysis will also be undertaken to compare population groups with different levels of health literacy. Where statistical pooling is not possible the findings will be presented in narrative form including tables and figures to aid in data presentation where appropriate.

Conflicts of interest

The authors declare that there are no conflicts of interest.


We would like to acknowledge Professor Diane Morin for her contribution to the initial conception of this systematic review.


1. Schenker Y, Meisel A. Informed consent in clinical care: practical considerations in the effort to achieve ethical goals. JAMA. 2011;305(11): 1130-1.
2. Schloendorff v Society of New York Hospitals. 211 N.Y. 125, 105 N.E. 92, 1914.
    3. Williams vs Menehan. 379 P.2d 292, Kansas, 1963.
      4. Departement of Health. Reference guide to consent for examination or treatment. 2nd ed. 2009. [Internet] [cited 2015 July 15]. Available from:
        5. Herbert V. Informed consent - A legal evaluation. Biomedical and Health Research, European Commission Directorate - General XII Science, Research and Development. Amsterdam: IOS Press.1980;46(S4): 1042-44.
          6. Beauchamp TL, Childress JF. Principles of biomedical ethics. New-York: Oxford University Press.2001.
            7. Hall JK. Nursing ethics and law. Philadelphia: WB Saunders Company.1996.
              8. Leino-Kilpi H, Valimaki M, Arndt M, Dassen T, Gasull M, Lemonidou C et al. Patient's autonomy, privacy and informed consent. Biomedical and Health Research, European Commission Directorate. 2000.
                9. World Health Organisation. Health Literacy. The Solid Facts. 2013. [Internet] [cited 2015 March 7] Available from:
                  10. Sørensen K, Van den Broucke S, Fullam J. Doyle G, Pelikan J, Slonska Z, et al. Health literacy and public health: A systematic review and integration of definitions and models. BMC Public Health. 2012;12: 80.
                  11. Haun JN, Valerio MA, McCormack LA, Sørensen K, Paasche-Orlow MK. Health literacy measurement: an inventory and descriptive summary of 51 instruments. J Health Commun.2014; 19(Suppl 2): 302-33.
                  12. Altin SV, Finke I, Kautz-Freimuth S, Stock S. The evolution of health literacy assessment tools: a systematic review. BMC Public Health. 2014;14: 1207.
                  13. Sørensen K, Van den Broucke S, Pelikan JM, Fullam J, Doyle G, Slonska Z, et al. Measuring health literacy in populations: illuminating the design and development process of the European Health Literacy Survey Questionnaire (HLS-EU-Q). BMC Public Health. 2013;10(13): 948.
                  14. Chew LD, Bradley KA, Boyko EJ. Brief questions to identify patients with inadequate health literacy Fam Med. 2004;36(8): 588-94.
                    15. Sørensen K, Pelikan JM, Röthlin F, Ganahl K, Slonska Z, Doyle G, et al. Health literacy in Europe: comparative results of the European health literacy survey (HLS-EU). Eur J Public Health. 2015;5(pii): ckv043.
                      16. Baker DW, Williams MV, Parker RM, Gazmararian JA, Nurss J. Development of a brief test to measure functional health literacy. Pat Educ Couns. 1999;38: 33-42.
                        17. Berkman ND, Sheridan SL, Donahue KE, Halpern DJ, Viera A, Crotty K, et al. Health literacy interventions and outcomes: An updated systematic review. Evid Rep Technol Assess. 2011;199: 1-941.
                        18. Mancuso CA, Rincon M. Asthma patients assessments of health care and medical decision making: the role of health literacy. J Asthma. 2006;43: 41-4.
                        19. Barragan M, Hicks G, Williams MV, Franco-Paredes C, Duffus W, Del Rio C. Low health literacy is associated with HIV test acceptance. J Gen Intern Med. 2005;20: 422-25.
                        20. Sherlock A, Brownie S. Patients’ recollection and understanding of informed consent: A literature review. ANZ J Surg. 2014;84(9): 207-10.
                        21. Walsh K. Re: Patients’ recollection and understanding of informed consent: A literature review. ANZ J Surg. 2014;84(9): 695.
                        22. Ley R, Forio T. The use of readability formulas in health care. Psychol Health Med. 1996;1(1): 7-28.
                        23. Davis TC, Crouch MA, Wills G, Miller S, Abdehou DM. The gap between patient reading comprehension and the readability of patient education materials. J Fam Pract. 1990;31(5): 533-38.
                        24. McCarthy DM, Leone KA, Salzman DH, Vozenilek JA, Cameron KA. Language use in the informed consent discussion for emergency procedures. Teach Learn Med. 2012;24(4): 315-20.
                        25. Protheroe J, Rowlands G. Matching clinical information with levels of patient health literacy. Nurs Manag. 2013;20(3): 20-1.
                        26. Zenklusen SI, Bischoff T, Panese F, Bodenmann P. Low health literacy: barrier to optimal care. Rev Med Suisse. 2012;8(340): 1016-20.
                          27. Sheridan SL, Halpern DJ, Viera AJ, Berkman ND, Donahue KE, Crotty K. Interventions for individuals with low health literacy: A systematic review. J Health Commun. 2011;16(3): 30-54.
                          28. Schenker YL, Fernandez A, Sudore R, Schillinger D. Interventions to improve patient comprehension in informed consent for medical and surgical procedures: A systematic review. Med Decis Making. 2011;31(1): 151-73.
                          29. Aldoory L, Barrett Ryan KE, Rouhani AM. Best Practices and New Models of Health Literacy for Informed Consent: Review of the Impact of Informed Consent Regulations on Health Literate Communications. Commissioned Paper for the Institute of Medicine. 2014. [Internet] [cited 2015 April 10]. Available from:˜/media/Files/Activity%20Files/PublicHealth/HealthLiteracy/Commissioned-Papers/Informed_Consent_HealthLit.pdf
                            30. Davis TC, Fredrickson DD, Arnold C, Murphy PW, Herbst M, Bocchini JA. A polio immunization pamphlet with increased appeal and simplified language does not improve comprehension to an acceptable level. Pat Educ Couns. 1998;33(1): 25-37.
                              31. Lorenzen B, Melby CE, Earles B. Using principles of health literacy to enhance the informed consent process. AORN J. 2008;88(1): 23-9.
                              32. Kang EY, Fields HW, Kiyak A, Beck FM, Firestone AR. Informed consent recall and comprehension in orthodontics: traditional vs improved readability and processability methods. Am J Orthod Dentofacial Orthop. 2009;136(4): 488.e1-13.
                              33. Smith SK, Trevena L, Simpson JM, Barratt A, Nutbeam D, McCaffery KJ. A decision aid to support informed choices about bowel cancer screening among adults with low education: randomised controlled trial. BMJ. 2010;341:c5370.
                              34. Matsuyama RK, Lyckholm LJ, Molisani A, Moghanaki D. The value of an educational video before consultation with a radiation oncologist. J Cancer Educ. 2013;28(2): 306-13.
                              35. Tamariz L, Palacio A, Robert M, Marcus EN. Improving the informed consent process for research subjects with low literacy: A systematic review. J Gen Intern Med. 2013;28(1): 121-6.
                              36. Ratzan SC, Parker RM. Introduction. In: Selden CR, Zorn M, Ratzan SC, Parker MR (eds). National Library of medicine Current Bibliographies in Medicine: Health Literacy. NLM Pub. No. CBM 2000-1. Bethesda, MD: National Institutes of Health, US Department of Health and Human Services. 2000. [Internet] [cited 2015 October 01] Available from:
                                37. Institute of Medicine. Health literacy: A prescription to end confusion. Washington, DC: National Academies Press. 2004.

                                  Appendix I: Appraisal instruments

                                  MAStARI appraisal instrument

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                                  Appendix II: Data extraction instruments

                                  MAStARI data extraction instrument

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                                  adults; health care intervention; health literacy; informed consent; medical intervention; numeracy

                                  © 2015 by Lippincott williams & Wilkins, Inc.