Assessing risk of bias in comparative diagnostic accuracy studies using QUADAS-C

Session Type
Workshop - training
Screening and diagnostic test accuracy synthesis methods
Target audience
Anyone interested in diagnostic test evaluation, including review authors, study investigators, and decision-makers.
Level of difficulty

Background: Diagnostic Test Accuracy reviews addressing comparative questions may include studies directly comparing index tests in the same study group. As these comparative accuracy studies aim to estimate the difference in accuracy between tests (rather than solely the accuracy of each test), we need to consider additional sources of bias specific to test comparisons. The QUADAS-C tool, an extension to QUADAS-2, considers these additional sources of bias and is endorsed by Cochrane for assessing risk of bias in comparative accuracy studies.
Objectives: to learn how to assess risk of bias in comparative accuracy studies using QUADAS-C.
Description: First we will briefly discuss about possible study designs for comparing the accuracy of two tests (10 minutes). We will then brainstorm, in small groups, which shortcomings could be present across the domains Patient Selection, Index Test, Reference Standard and Flow and Timing (20 min). Subsequently the structure of and items in QUADAS-C will be presented (10 minutes). Lastly, we will evaluate a comparative accuracy study in small groups using QUADAS-C (30 min), followed by a plenary discussion of any discrepancies between assessors (20 min). Importance to patients: while this concerns a methodological topic and does not contribute directly to patient health, using biased research may lead to misleading recommendations about diagnostic tests.