Impact of a Patient Decision Aid Intervention

A cancer diagnosis is life-changing and followed by complex decisions about treatment options. Often the decision about which treatment to choose is based on risks and benefits, although the benefit-harm ratios are unknown. In these situations, a patient decision aid can be helpful in explaining the options, clarifying the patient's preferences and acting as an adjunct to the clinician's counselling, supporting the patient in complex decisions about their diagnosis. Studies evaluating patient decision aids have used a wide range of outcome measures as well as formats and settings. Most studies have focused on patient decision aids used either within the consultation or delivered pre-consultation, but there are no randomised, controlled studies comparing the two. There is a lack of evidence of the impact of patient decison aids used pre-consultation versus in-consultation, as timing and format of the patient decision aid intervention may affect how useful the tool is to the patient. The aim of this project is therefore to deepen our understanding of the patient's engagement in and preparation for the decision making process in a randomised, controlled trial comparing a digital pre-consultation and paper-based in-consultation patient decision aid. 274 patients with colorectal and breast cancer are enrolled in the study. Data are collected at both patient and consultant perceived level as well as an observed level of shared decision making (SDM). A secondary analysis of the data collected in the study will form the basis of a study testing the convergent validity of the patient-reported measures by comparing them to the observed level of patient involvement. During the last decade, the strong move towards increased SDM has led to development of several measurement scales, and there is a demand for convergent validity studies, as there is no gold standard to evaluate SDM behaviors. Previous validity studies have various shortcomings.