This is a cross-sectional survey of the effect of varying levels of benefit, risk, and cost of diagnostic testing on the probability of electing to pursue testing in two hypothetical clinical scenarios among a convenience sample of patients in the University of Michigan Emergency Department (ED). Study designParticipants were presented with two hypothetical clinical scenarios, in random order, in which they present to the ED with either low-risk chest pain (CP) or minor traumatic brain injury (mTBI). A subset of the mTBI respondents with children under the age of 18 were given a similar scenario with their child as the patient (mTBI-child) instead of themselves (mTBI-adult). A structured survey was then administered in which participants were asked to decide if they would pursue diagnostic testing given different levels of benefit (the chance of having an accurate diagnosis of disease requiring medical intervention), risk (the development of cancer within ten years due to ionizing radiation from the test), and cost (an additional test-specific copay) associated with the diagnostic test. The survey was read aloud to all patients to reduce any misunderstandings caused by difficulties with reading or seeing. Participants responded to both clinical scenarios and were randomly assigned a benefit and risk value of 0.1% or 1%, and a cost of $0 or $100 for the diagnostic test. These values were chosen to maximize the sensitivity of the study to detect differences in patient preferences based on a preliminary study performed by the authors (mTURK methods paper et al), which indicated that the largest variation in patients accepting or declining diagnostic testing was for benefit and risk levels of 0.1% and 1% and cost levels of $0 and $100. Additionally, risk values of 0.1% and 1% were felt to represent a realistic chance of developing cancer from diagnostic testing with radiation (Factor, Acetylhydrolase, & Levy, 2008). In order to improve participants’
incorporation of numerical values into their decision-making (Schapira, Nattinger, & McAuliffe, 2006), patients were presented with decision aids where risk and benefit values were presented as a ratio and percentage, as well as with an image representing values of 1 in 1000 and 1 in 100. The full transcript of the scenarios and survey is available in the online appendix. Setting and ParticipantsA convenience sample of adult patients over the age of 18 who presented to the University of Michigan ED during the daytime hours between June and August 2015 were recruited in the study until 900 completed surveys were achieved. Patients presenting with chest pain or recent head injury were not recruited so as to not interfere with their clinical course. Additionally, patients who were under contact precautions or in resuscitation bays were not approached. No compensation was offered for completion.