Asch DA, Patton JP, Hershey JC. Knowing for the sake of knowing: the value of prognostic information

Robert Wood Johnson Foundation Clinical Scholars Program, University of Pennsylvania School of Medicine, Philadelphia 19104-4283.
Medical Decision Making (Impact Factor: 3.24). 02/1990; 10(1):47-57. DOI: 10.1177/0272989X9001000108
Source: PubMed


In evaluating diagnostic tests, traditional methods in decision analysis often emphasize how the results of the test will or will not affect patient management. Clinicians are advised to avoid testing if the results will not alter treatment strategy or other management plans. But patients may be interested in the prognostic information that testing provides even if it is not used to guide treatment. The authors present a model that defines this prognostic information as the expected deviation from the prior probability of disease. The model generates utility functions that are curvilinear over prior probabilities. Whereas the traditional threshold approach to medical decision making produces at most three zones of management strategy (withhold, test, and treat), the incorporation of prognostic information into threshold analysis produces two additional zones (test but withhold anyway, and test but treat anyway). Conditions under which one or both of these additional zones will appear are described. The model justifies the practice of performing tests that cannot alter management plans; it explains the unwillingness of some patients to undergo diagnostic testing when they fear unwanted results; and it provides a method for quantifying the sensitive nature of confidential tests. The model is illustrated using the antibody test for the Smith antigen. This test has a high specificity but a low sensitivity for lupus erythematosus. Clinicians may use the test because a positive result will support their prior suspicion of disease even though they may not change their management strategy if the test result is negative. The advantage of testing in this setting lies in the test's potential for establishing with virtual certainty that the disease is present. Thus, the test is valued for the prognostic information it provides apart from its effect on patient management.

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Available from: John C Hershey, Dec 12, 2014
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    • "owever, patients may value information from a test even when the information does not affect treatment.(Lee, Neumann, & Rizzo 2009) For example, test information may provide reassurance to patients and physicians that serious disease is absent,(Blackmore et al. 1999;Hillman, Amis, Weinreb, & Neiman 2005) especially for those identified as at risk.(Asch, Patton, & Hershey 1990;Kenen 1996) A new test may be valuable because it provides quicker access to such information.(Baker, Atlas, & Afendulis 2008) In addition, research also shows that people dislike uncertainty(Shogren 2005;Viscusi, Magat, & Huber 1991) and so may prefer situations in which they have better information about their health or about their ch"
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    • "The analogy to the demand for tax advice in Beck et al. is striking, including the consequences of interpreting results as "good" or "bad" news. In the case of bad news, Asch et al. (1990, 52) relate the utility of prognostic information to theories of regret and disappointment, which ties into the literature on inconsistencies in choice tasks under uncertainty (also see Bell 1985). A second and related explanation is that Beck et al. (1996) may be observing the consequences of loss aversion, which has been shown to skew decisions in both riskless choice (Tversky and Kahneman 1991) and in the evaluation of risky prospects (Tversky and Kahneman 1992). "

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