Yasmina Okan - Current challenges when using numbers in patient decision aids

This work reflects the collaboration of a panel of international experts on risk communication from different institutions across Australia (University of Sydney), the Netherlands (Amsterdam UMC), and the US (University of Oregon, Tufts University, University of Utah, University of Michigan, Maine Medical Center Research Institute). The reference and abstract are below:

Trevena, L., Bonner, C., Okan, Y., Peters, E., Gaissmaier, W., Han, P., Ozanne, E., Timmermans, D., & Zikmund-Fisher, B, J. (in press). Current challenges when using numbers in patient decision aids: Advanced concepts. Medical Decision Making

Background: Decision aid developers have to convey complex task-specific numeric information in a way that minimises bias and promotes understanding of the options available within a particular decision. While our companion paper summarises fundamental issues, this paper focusses on more complex, task-specific aspects of presenting numeric information in patient decision aids.

Methods: As part of the International Patient Decision Aids Standards (IPDAS) third evidence update, we gathered an expert panel of nine international experts who revised and expanded the topics covered in the 2013 review working in groups of 2-3 to update the evidence, based on their expertise and targeted searches of the literature. The full panel then reviewed and provided additional revisions, reaching consensus on the final version.

Results: Five out of the 10 topics addressed more complex task-specific issues. We found strong evidence for using independent event rates and/or incremental absolute risk differences for the effect size of test and screening outcomes. Simple visual formats can help to reduce common judgment biases and enhance comprehension but can be misleading if not well-designed. Graph literacy can moderate the effectiveness of visual formats and hence should be considered in tool design. There is less evidence supporting the inclusion of personalised and interactive risk estimates.

Discussion: More complex numeric information such as the size of the benefits and harms for decision options, can be better understood by using incremental absolute risk differences alongside well-designed visual formats that consider the graph literacy of the intended audience. More research is needed into when and how to use personalised and/or interactive risk estimates since their complexity and accessibility may impact on their feasibility in clinical practice.