Decision aids and uptake of screening

Two linked papers assessed patient information in the prevention of bowel cancer: Kirkegaard and colleagues (doi:10.1136/bmj.c5504) encouraged adherence with lifestyle recommendations,1 and Smith and colleagues (doi:10.1136/bmj.c5370) facilitated informed screening choices.2 Smith and colleagues’ study evaluated a decision aid to inform adults’ choices about faecal occult blood testing. The results raise the possibility that uncritical acceptance of informed choice initiatives may cause more harm than good.

Decision aids help people decide between two or more options. They are based on evidence from the decision sciences on how judgments and decisions are altered when facts are presented in different ways. Decision aids include several components that limit the influence that the style of presentation has on judgments and choices, encourage people to attend to the pertinent facts, encourage people to think explicitly about the facts and how they fit with their existing beliefs, and help them use these evaluations to reach a decision.3

Decision aids help patients clarify why the treatment or test option they choose is better for them than the one they reject.4 Patients who use decision aids are more aware of the choices offered and their consequences, more realistic about the risks and values of the options, more satisfied with the choice made, and engaged in a more informed decision making process. However, evidence is needed to identify which components facilitate which patient measures, in which disease contexts, and why.3

Smith and colleagues evaluated a decision aid for faecal occult blood testing.2 It was designed specifically for adults with lower levels of education by combining text written in an accessible way with illustrations to enhance attention and recall, and a supplementary video. Fewer than half of those sampled used the video and then only after reading the written information. Both decisional conflict and anxiety scores were low, suggesting that adults do not find the choice about bowel cancer screening difficult to make. Even so, compared with the standard information, the decision aid significantly increased adults’ knowledge of the risks of testing and their perception of having made an informed decision. Unusually, the decision aid influenced adults’ choices; test uptake was significantly lower in the decision aid group compared with controls (59% in decision aid group v 75% in controls; 16% difference, 95% confidence interval 8% to 24%).

Because the study found that decision aids improved the ability to make an informed decision, Smith and colleagues recommended that such aids should be integrated within primary care.2 Decision aids are appropriate when there is insufficient evidence to indicate the best medical choice, patients’ preferences are central to the choice, or the consequences of the options involve serious risks (or a combination of all three). However, evidence shows that faecal occult blood testing reduces mortality from bowel cancer,5 and a key objective of bowel cancer screening programmes is to increase uptake.6 A more appropriate framework in this context might be to structure the facts with reference to evidence on how to improve understanding of the disease, test, and treatment and to facilitate adherence with testing7—that is, a policy of informed uptake rather than informed decision making.

Smith and colleagues’ findings are consistent with other decision aid evaluations.2 4 The authors provide some explanation for their seemingly paradoxical findings that adults who received the decision aid were more informed and had positive attitudes to bowel cancer screening but were less likely to have faecal occult blood testing. Their findings support their view that the participants’ judgments were influenced by the way risk was presented. Although it is important to describe risks clearly, the amount of space given to the presentation of risk within decision aids might be disproportionate to the conceptual facts adults consider when offered screening, and this may overemphasise the risks associated with screening compared with the value of preventing the disease. In addition, people reason more about their beliefs and feelings towards options when using a decision aid.8 It may be that this additional effort is sufficient to reduce people’s motivation to carry out this test, which many people find distasteful.6

For mortality from bowel cancer to be reduced, adults need to adhere to lifestyle recommendations or have the screening test (or both).1 2 Making interventions to increase informed uptake of faecal occult blood testing more effective might need changes to the information, so that the risks and benefits of screening are described clearly within a framework that encourages adherence to recommendations, and changes to the screening pack (perhaps the addition of disposable gloves), so that barriers to performing it are reduced (personal communication, F Crawford, 2010).7 Decision aids are one type of intervention that informs patients’ choices. The content and structure of information interventions should differ depending on their purpose—whether they aim to inform and prepare or enable decision making or support uptake. Before interventions are adopted in practice, evidence is needed that the intervention informs patients and meets the service need.