Ensuring informed consent is considered an ethical principle for medical research involving human subjects and is enshrined in the Declaration of Helsinki (1). The basis of informed consent is the patient's informed decision about whether he or she wants to undergo a medical procedure, prefers another one, or refuses it (2). Informed decisions for or against medical interventions require evidence-based health information that provides comprehensible and transparent information about the benefits and harms of all treatment options (3, 4). However, information often fails to meet evidence-based and risk communication criteria (5–7), which means that not all people facing a health decision are able to make a decision based on evidence-based knowledge and in line with their personal preferences (informed choice) (3). In addition, despite their general effectiveness, public health interventions, e.g. public health messaging, can lead to the disadvantage of certain social groups (intervention generated inequalities) if equal access to them is not ensured (8–10). What are possible barriers? Known social determinants of health work to the disadvantage of certain groups (10, 11). They are also a key determinants of health literacy (12): individual differences in the ability to search for, understand, evaluate, critical assess and use health information to make informed choices (13, 14). In addition to socio-demographic factors such as education, income or older age, it is not uncommon for language barriers to impede access to health-related information (15). Thus, different communication channels, translations and initiatives to bring health information to those facing health decisions are required.
Often health information consists only of words, although there is evidence that visual representations and images - particularly icons with few words - may improve knowledge/understanding, especially in populations with low health literacy (16). Furthermore, text-heavy health information (e.g. package leaflets) is often written at a higher reading level, making it inaccessible to people with lower health literacy (16). As a result, uninformed decisions are made, that is, decisions are made without sufficient knowledge of the benefits and harms and of the treatment alternatives, which are not consistent with attitudes for or against the medical treatment (3). Why is this a problem? Overall, uninformed decisions are more likely to lead to decisional regret, reduced ability to use medicines appropriately, poorer health outcomes and let people less likely opt for a follow-up treatment (e.g., booster vaccinations) (17).
Unfortunately, disadvantaged groups less often make informed decisions and are more likely to experience higher decision regret than advantaged groups (10, 18). A representative observational study from 2015 found that among women invited to the nation-wide mammography screening programme in Germany for the first time, women with low and medium levels of education were more likely to make an uninformed decision than women with high levels of education. Women with an immigrant background were only slightly more likely to make an uninformed decision than women without an immigrant background. However, women with a Turkish immigrant background were more likely to make an uninformed choice than women with no immigrant background (18). In 2019, these differences were still found in terms of knowledge, which is central to informed decision making. Women with less education and an immigrant background were more likely to have insufficient knowledge about the benefits and possible harms of mammography screening. Sufficient knowledge was again associated with higher education and was lowest among Turkish women (19).
To reduce inequities and achieve high quality health care, structures and approaches must enable disadvantaged people to access and navigate the health system to effectively manage their health and care. Evidence-based health information (EBHI) and decision aids (DAs) are key components for improving health care by enabling more people to make informed decisions (20). Taking into account the best evidence currently available, they present information on the course and effects of diseases and on the benefits and harms of medical interventions (including early detection, diagnosis and treatment) in a transparent and understandable manner, based on patient-relevant outcomes (21). In contrast to DAs, EBHI often has a broader focus and is not directly aimed at preference-based decision making. DAs use tools (value clarification tools) to help identify these (22). The benefits of DAs over standard care (no evidence-based information or no intervention) are already clear. In a Cochrane review (22) the effect of DAs on people who are about to make a decision for or against a medical intervention (e.g. surgery, cancer screening, drug treatment) was investigated. Different formats of DAs (including written, web-based, video) in different settings were analysed in the 105 randomized controlled trials included. The review found that DAs have a positive effect on knowledge, information and perception of values, and that decision makers are likely to take a more active role in the decision-making process and have a better perception of risk (22).
However, despite their overall effectiveness, there is a risk that only certain groups of the population will benefit from EBHI and DAs. Because although they are “target group oriented”, the factors that lead to inequity in terms of shared and informed decision-making have not yet been sufficiently taken into account in their development process (10, 23). For example, there are many patient-oriented materials written at an advanced level, which makes the materials less accessible to people with reading difficulties, lower education, health literacy or socioeconomic status (SES) (16, 24, 25). In general, only few studies have looked specifically at the impact of shared decision making (SDM) or informed decision making in groups that are more likely to have communication barriers due to their racial or ethnic background and/or level of education (23, 26). In a systematic review with meta-analysis of randomized controlled trials, the authors (26) examined whether patient DAs and other SDM interventions improve outcomes or reduce health inequalities in socially disadvantaged populations. The authors found that SDM interventions for disadvantaged populations improve for example knowledge and informed choice. However, they could not determine which interventions were most effective in promoting SDM and whether there are key features from which all or the disadvantaged can benefit. Further, the authors state that there is a lack of evidence on the effectiveness of decision-making interventions for disadvantaged people compared to non-disadvantaged people. Nevertheless, they conclude that their research suggests that targeted interventions - interventions that are tailored to a very specific group (e.g. people with limited health literacy) - might narrow the gap in care between disadvantaged and non-disadvantaged populations (27). Preliminary results from an ongoing systematic review by the authors of this manuscript (28), which is registered through PROSPERO (CRD42018103456), also indicate that only few studies have examined the extent to which disadvantaged groups have been considered in evaluating (evidence-based) health information and decision aids in randomized controlled trials, and whether and to what extent inequity is reduced.
Another review from 2016 (20) looked at the extent to which disadvantaged groups were considered in the development and evaluation of cancer screening and treatment decision aids in trials in the USA. 23 of the 39 included studies evaluated decision aids that considered socially disadvantaged groups. Only 17 trials involved disadvantaged people in the development of the decision aids. The authors note that a number of issues and medical interventions that would be relevant to specific disadvantaged groups because of their higher morbidity and mortality are not yet addressed in decision aids in the US. In addition, disadvantaged groups are more likely to be unaware of treatment alternatives, such as watchful waiting or not participating in screening, and more likely to have the misconception that decision aids are designed to increase screening participation rather than to support decision making (20).
The aim of our study is to assess whether evidence-based fact boxes can facilitate informed decisions for laypeople from different social backgrounds, and to explore whether they contribute to reducing inequity in health care by improving shared decision-making.
Fact boxes provide a tabular or graphical overview of the benefits and harms of medical options through transparent risk communication (29). They are used to inform a range of health decisions, such as medical treatments, cancer screening and vaccinations. By reducing complexity and balancing evidence, they aim to promote informed decisions rather than predetermined behavioral change (30). As such, they go hand in hand with current Western health standards and ethical principles that oppose persuasion or nudging, as it violates informed choice and undermines the trustworthiness and credibility of the communicator and vaccinator (30, 31). Fact boxes are developed according to the recommendations of the German guideline evidence-based health information (19, 30). This includes development and evaluation according to the Medical Research Council (MRC) guideline Development and Evaluation of Complex Interventions (32). They are developed in a multi-stage process, and their individual elements are tested and adapted where possible (33). Several experiments have shown that fact boxes support informed decisions by improving for example risk perception, short-term knowledge/knowledge recall, comprehension (30, 34–37).
At present it is unclear whether fact boxes can be an effective tool in the real world. Further, fact boxes have been tested with the lay public, but only three studies analysed its effect by vulnerability factors. A recent randomised controlled pilot study of three numerical presentation formats of fact boxes to laypeople found indications that the acquisition of verbatim knowledge was lower among participants with lower than among participants with higher levels of education for the formats percentages and graphic chart. However, there were no differences in gist knowledge and the frequency format showed comparable results between the two levels of education (37). In another study examining the effect of COVID-19 vaccine fact boxes on vaccination knowledge and assessment of the benefit-harm ratio of mRNA vaccination, the effect was greater among people with higher education or income than among people with lower education (30). In a study of whether fact boxes or text-only formats on antibiotics for ear infections or flu vaccines with the same content led to better understanding of the potential harms and benefits of each option, fact boxes appeared to improve understanding at all levels of numeracy (36).
Another aim of our study is to find out to what extent evidence-based fact boxes can be integrated into the communication of health educators (e.g. doctors) in standard care and outreach settings, and what added value they have compared to conventional information or no information at all in supporting SDM. SDM means that the doctor and the patient make decisions about health care together in an interactive and equal process, provided that health professionals make available their knowledge, experience and the latest scientific evidence, but also that patients are fully informed and involved in all important aspects of medical decision-making (38, 39). While SDM interventions have varying effects on patient-relevant outcomes such as mortality, morbidity and health-related quality of life the grade of informed choice can be considered a baseline outcome of SDM (2).
Although there is evidence for the benefits of SDM interventions (e.g. decision aids, DAs) in improving people's knowledge of risks and benefits, feeling informed, and clarity about their values in a variety of decision-making contexts (22), and thus for their use in clinical practice, the real-world effects of implementing EBGI as an SDM intervention are still unclear. What are the prerequisites, facilitators and barriers for people to benefit from them in practice and for clinicians to implement them? Already in 2013, the authors of a review called for more research into the extent to which EBHI and DAs are effective in medical care, as they are not yet widely used in medical practice (40). Also in 2019, only 21% of DAs were introduced after trials and further 7% were part of implementation studies. Barriers included outdated evidence in DAs and disagreement among clinicians about the use of DAs (41).
This paper reports on the study protocol of an implementation study and equity evaluation of COVID-19 and influenza vaccination fact boxes in different health education settings in Germany. The trial was prospectively registered on clinicaltrials.gov (registered on 29 September 2023, not yet published).