The Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) has been widely accepted in the assessment of diagnostic accuracy and quality. However, it is not suitable for assessing risk of bias in studies comparing diagnostic accuracy. The current common practice in systematic reviews is to derive comparative accuracy from non-comparative diagnostic accuracy studies, which is inherently biased. The QUADAS group developed the QUADAS-Compare (QUADAS-C) tool for assessing the risk of bias in comparative diagnostic accuracy studies. It was officially launched in October 2021. QUADAS-C retains the same 4-domain structure as QUADAS-2: patient selection, index test, reference standard, and flow and timing. It also includes an additional 14 signaling questions and 4 risk of bias questions. This allows researchers to identify high-quality research evidence and avoid bias in research design and conduct. This article interpreted the basic situation, evaluation items, evaluation standards, and usage methods and procedures associated with QUADAS-C to provide references for domestic users.
The QUADAS-2, QUIPS, and PROBAST tools are not specific for prognostic accuracy studies and the use of these tools to assess the risk of bias in prognostic accuracy studies is prone to bias. Therefore, QUAPAS, a risk of bias assessment tool for prognostic accuracy studies, has recently been developed. The tool combines QUADAS-2, QUIPS, and PROBAST, and consists of 5 domains, 18 signaling questions, 5 risk of bias questions, and 4 applicability questions. This paper will introduce the content and usage of QUAPAS to provide inspiration and references for domestic researchers.