Authors
- Perrenoud, Beatrice
- Velonaki, Venetia-Sofia
- Bodenmann, Patrick
- Ramelet, Anne-Sylvie
Abstract
Review question/objective: The aim of this systematic review is to establish the best available evidence of the effectiveness of health literacy interventions on the informed consent process for health care users. The specific review question is:
What is the effectiveness of health literacy interventions on health care users' informed consent to health procedures processes?
Background: Informed consent is a fundamental principal in the health care context which nowadays includes the patient's capacity to judge and to be involved in the decision making concerning their care that ensures that the care received reflects their goals, preferences and values.1 The importance of obtaining a valid consent before any medical procedure is well-established. In a US court case in 19142, it was stated that it is the right of any adult with the capability of making decisions concerning his own body, and that any surgical operation without the patient's consent could be considered as an assault. In another US court case3, the court stated that it is a doctor's duty to make a reasonable disclosure to his patient of the nature, probable consequences and dangers of the proposed treatment to the patient. The application of the doctrine of informed consent as a legal procedure may slightly differ from country to country or from state to state, and may have different forms even within the same country. For example in the UK, consent can be written, verbal or non-verbal/implied, and a written consent form is not the actual consent itself but merely serves as evidence that consent has been given. If the elements of voluntariness, appropriate information and capacity have not been satisfied, a signed informed consent form will not make the consent valid.4 Nowadays it is widely accepted that prior to the application of any medical procedure, its benefits, risks and alternatives must have been explained to the patient, and the competent patient should have voluntarily and understandingly consented.5 Hence, the informed consent refers both to the health professional's obligation of information disclosure to the patient and to the quality of the patient's understanding and decision making.6 In other words, it does not refer to the single moment of the agreement, but to the whole complex process of gaining information, deciding and consenting.7 Several factors may restrict informed consent, including the patient's competence, provision of limited information, ineffective communication between patients and professionals, the hospital environment itself and privacy problems.8
According to the World Health Organization (WHO), people are increasingly urged to make choices for themselves or for their family members in regards to health care use. However, at the same time, inadequate or problematic health literacy skills have been reported in approximately half of the adult population in eight European countries.9 "Health literacy is linked to literacy and entails people's knowledge, motivation and competences to access, understand, appraise and apply health information in order to make judgments and take decisions in everyday life concerning health care, disease prevention and health promotion to maintain or improve quality of life during the life course".10(p3) There are many instruments measuring either health literacy in general or some dimensions of health literacy (e.g. numeracy), health literacy related to specific issues (e.g. nutrition, diabetes) or health literacy of specific populations (e.g. adolescents).11,12 The diversity of existing instruments, which includes diversity in terms of scoring and ranges, makes the comparison of the results of different studies difficult.11,13 Index thresholds and ranges for different levels of health literacy for most tools were set based either on that of other well established health literacy instruments used in the same study,14 or on experts' assessments of the required health literacy scores.15 Adequate health literacy could be considered as the capacity of successfully completing most tasks required to function in the health care setting.16
Low or inadequate health literacy has been found to have several adverse effects on health and health care use: reduced ability to take medications properly and to interpret labels and health messages, poorer overall health status and higher risk of mortality in seniors, increased emergency department and hospital use, and decreased use of preventive interventions.17
Health literacy and informed consent
Most studies examining the relationship between health literacy and informed consent conclude that patients with low health literacy are less likely to participate in decision making concerning their health care.18,19 According to a recent literature review20, health care users' literacy, together with other factors, were found to be important determinants of a patient's capacity to provide fully informed consent. According to this review, 21 to 86% of the patients were able to recall the potential risks and complications of their medical procedure. This percentage may be even lower because most of the included studies referred to self-reported recall, which may be a flawed measure.21 According to the literature, much of the written material related to the informed consent is too difficult for health care users to understand.22,23 In addition, in their study, McCarthy et al.24 observed that during consultations, physicians spoke and used significantly more complex language than their patients, which may result in inappropriate communication for the patients, mainly for those with limited literacy. The situations described above may raise a number of critical legal and ethical problems.23 Health professionals, who shape the conditions of interactions with the patient, are responsible for adapting appropriate interventions, such as communication approaches25 that take into account patients' health literacy.26 These interventions could have a major contribution to the improvement of the informed consent process.
Interventions
Sheridan et al.27 conducted a systematic review on interventions designed to reduce the effects of limited health literacy in general. Some of the outcomes of the included studies were comprehension and behavioral intent, outcomes which could be strongly related to the informed consent process. Without making any distinction of the studies referring to the informed consent process, they conclude that several health literacy interventions, for example, adding video to narrative, could improve an individual's comprehension. Schenker et al.28 conducted a systematic review on the interventions to improve patient comprehension of medical and surgical procedures, including articles published until 2008. One of their conclusions was that, in most studies, while particular attention is needed for interventions provided to patients with limited literacy, the literacy of the patients was not addressed or assessed.
Since then, many articles on health literacy and informed consent have been published. According to a recent review on best practices and new models of health literacy for informed consent29, which includes papers published from 2004 to 2014, over half of the collected articles were published since 2010. This review, which is limited to literature within the US and its territories, and does not focus on the evaluation of the recommended practices in the literature, concludes that different tactics for simplifying written documents and clarifying verbal exchanges, and the use of multimedia formats and computerized exchanges might ameliorate constraints to health literate communications required for informed consent.
Studies have evaluated the effectiveness of health literacy interventions which aim to improve the informed consent process.30,31,32,33,34 Improvement of the informed consent process may refer not only to the patients' comprehension but also, for example, to the recall of the information provided, to their intention to ask for clarifications, or to their satisfaction with the procedure. Interventions described and tested in the literature focus on the improvement of the print material, the process (e.g. the communication of the appropriate information) or both. Davis et al.30 conducted a randomized controlled trial to compare two polio vaccine pamphlets written at a sixth grade level - an international standardized pamphlet and an easy-to-read pamphlet - for the comprehension and preference among parents. Although the parents in the intervention group (N=304) achieved significantly higher comprehension than the control group (N=306) (65% vs 60%, p<0.005), the authors concluded that simplifying written material increases appeal but not the comprehension to an adequate level without use of instructional graphics. Similarly, Lorenzen et al.31 found that a reader friendly informed consent document to surgical procedures was more commonly read by the health care users as compared to the original consent document; however, no difference was found in terms of the participants' capacity to describe the procedure in their own words. Kang et al.32 evaluated recall and comprehension of orthodontic informed consent among pairs of children and their parents (N=90) applying three different informed consent procedures. According to this study, a combination of improving the readability of consent materials and the informed consent process (audio and visual cues) led to better recall for the patients and better recall and comprehension for their parents compared to an improved readability form or the usual informed consent form. Smith et al.33 used a randomized controlled trial to compare a decision aid (booklet and DVD) specifically designed for adults with low literacy skills (N=357) with a standard information booklet (N=173) on screening for bowel cancer. They found that the proportion of participants making an informed choice was 22% higher in the intervention group than in the control group (34% vs 12%, P<0.001). Matsuyama et al.34 demonstrated that an education video co-designed by an expert in patient health literacy improved patients (N=32) awareness about radiation therapy before they were asked to provide informed consent for this treatment. The mean number of correct responses by respondents increased 2.3 units in the 21-question survey after watching the video (p<0.0001; 95% CI: 1.3-3.0). Authors concluded that video intervention led to a significant improvement of knowledge regardless of the participants' health literacy level.
While interventions to improve the informed consent process for research subjects with low literacy have already been included in a recent systematic review,35 a search in the JBI Database of Systematic Reviews and Implementation Reports, the Cochrane Library, DARE and the Trip database did not locate any systematic review or protocol for a systematic review that identify health literacy interventions concerning informed consent to health procedures. For that reason, the aim of this systematic review is to identify, appraise and synthesize the best available evidence for interventions which improve the health care user's informed consent process, taking into account their health literacy, and to summarize the evidence on their effectiveness in enhancing the health care user's informed consent to health procedures processes. The results of this systematic review could be useful for both health care professionals and policy makers, as the informed consent is an essential part of everyday health care.
Definitions of terms
Informed consent"
"An informed consent is an individual's autonomous authorization of a medical intervention or of participation in research."5(p78) In this review we refer only to informed consent to a health care intervention.
Health literacy:
"Health literacy is the degree to which individuals have the capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions."36(para7) In this review health literacy refers to the consideration of at least one of the five skills of literacy proposed for health literacy studies by the Institute of Medicine report.37 These skills are reading, writing, numeracy, oral communication and listening comprehension.
Article Content
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.
Acknowledgements
We would like to acknowledge Professor Diane Morin for her contribution to the initial conception of this systematic review.
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Appendix I: Appraisal instruments
MAStARI appraisal instrument[Context Link]
Appendix II: Data extraction instruments
MAStARI data extraction instrument[Context Link]
Keywords: adults; health care intervention; health literacy; informed consent; medical intervention; numeracy