Should systematic reviews of diagnostic tests go beyond test accuracy?

Article type
Authors
Westwood M, Whiting P
Abstract
Background: Systematic reviews of diagnostic tests generally focus exclusively on test accuracy. Reviews that fail to adequately consider the clinical context of testing and its impact on patient outcome may result in conclusions that have limited clinical value. Objectives: To examine how issues beyond test accuracy are considered in published diagnostic reviews. To discuss our own experience in conducting these reviews and to assess whether a restriction to test accuracy studies would have changed findings. Methods: We examined a convenience sample of diagnostic (diagnosis, screening, monitoring, prognosis) abstracts from the DARE database (1998 to 2007) to determine whether they addressed questions beyond test accuracy. We recorded the clinical application of the test, areas outside test accuracy addressed, and whether or not conclusions incorporated these data. We assessed the contribution of information other than test accuracy data to reviews of diagnostic tests that we have conducted. Results: Our DARE sample included 234 abstracts: 13 from 2007; 25 per year from 2000 to 2006; 23 per year from 1999 and 1998. Of these, 33 (14%) included outcomes other than measures of test accuracy; 19 used these findings to inform their conclusions; 8 reported finding no evidence (of which 1 included the null finding in conclusions); and the remaining 7 reported data but did not use it in their conclusions. Additional outcomes included: adverse events (6 abstracts); changes to patient management (14 abstracts); changes to patient outcome (17 abstracts); patient preferences (5 abstracts); and test failure (7 abstracts). Our diagnostic reviews have sought data on the clinical effectiveness (changes to management and/or outcomes) as well as the accuracy of tests, adverse events, patient preferences and resource implications of test introduction. Data were generally sparse and of poor quality. Conclusions: A small proportion of published reviews assess issues beyond test accuracy and those that do find few additional studies. However, it remains important to frame the objectives and inclusion criteria of reviews of diagnostic tests to address all relevant aspects of test use, including, but not exclusively, accuracy.