Updating QUADAS: User experience informs the development of QUADAS-2

Article type
Authors
Westwood M1, Whiting P2, Rutjes A3, Mallet S4, Deeks J5, Sterne J2, Leeflang M6, Reitsma J7, Bossuyt P6
1Kleijnen Systematic Reviews Ltd, UK
2University of Bristol, UK
3University of Bern, Switzerland
4University of Oxford, UK
5University of Birmingham, UK
6University of Amsterdam, Netherlands
7University Medical Centre Utrecht, Netherlands
Abstract
Background: QUADAS is a widely used, evidence-based quality assessment tool, developed for use in systematic reviews of diagnostic test accuracy (DTA) studies. The experience of the QUADAS steering group, anecdotal reports, and feedback via Cochrane Collaboration members suggested some problems with QUADAS. We therefore decided to revise QUADAS using experience of its application, and new evidence regarding sources of bias and variation to produce QUADAS-2. This abstract describes evidence derived from user experience.

Objectives: To gather structured feedback from review authors who have used QUADAS, and to summarise the findings of studies that have evaluated QUADAS.

Methods: We sought information on users' experiences of QUADAS using a web-based questionnaire to elicit feedback from authors of Cochrane DTA reviews and protocols, and authors of reviews on DARE which had used QUADAS. We conducted a systematic review of studies that had evaluated QUADAS.

Results: 64 authors completed the questionnaire. The majority (70% to 89%) rated QUADAS as good or very good for coverage, ease of use, clarity and validity. Negative features highlighted were the mixing of questions relating to bias and applicability, and inability to use QUADAS to assess studies comparing multiple index tests. Approximately 15% of review authors reported omitting items on reporting quality from their QUADAS assessments. Despite guidance, 20% of review authors reported using QUADAS to calculate summary scores. Four studies evaluated QUADAS; key recommendations were that QUADAS-2 should be expanded to cover studies comparing multiple index tests and topics where follow-up is the reference standard.

Conclusions: The experience of review authors using QUADAS informed development of QUADAS-2 and was largely consistent with the experience and conceptual decisions of the steering group. The experience of QUADAS users will continue to be important in informing future developments and ensuring continued relevance and wide up-take.