Assessment of methodological quality (QUADAS-2)

Conversion of study characteristics and QUADAS items in existing reviews to QUADAS-2 domains

The QUADAS-2 tool (Whiting et al. 2011) was implemented in RevMan 5.2 for the assessment of methodological quality. However, RevMan 5.2 still supports methodological quality assessment using the old QUADAS and the old structure for Characteristics of included studies tables, see Assessment of methodological quality tables (QUADAS).

QUADAS-2 and Characteristics of included studies tables

For data entry purposes, due to considerable overlap between the expected content of the 'Study characteristics' table and that of the description expected for each domain of QUADAS-2, each included study has a study characteristics table integrated with a methodological quality table.  However when the review is published the tables are rendered separately. The study characteristics table can be previewed for each study in RevMan by right clicking on the study name and selecting View study characteristics.

The four domains—Patient Selection, Index Test, Reference Standard, and Flow and Timing—are mandatory.  All domains are assessed in terms of risk of bias and the first three domains are also assessed in terms of concerns regarding applicability. Signalling questions can be added or removed in each domain as appropriate for each review. Additional domains cannot be created except a domain called Comparative for specific comparative issues (in reviews that compare the accuracy of tests) which do not fit in any of the other domains.

To activate an item

  1. Open the properties for the characteristics of included studies table.
    Click the Properties icon next to the relevant domain.

  2. Choose the signalling question you wish to activate and check the box.

  3. Click OK.
    The properties window closes and the new signalling question is added to the table

User defined characteristics

The table has a predefined set of signalling questions for both risk of bias and concerns regarding applicability. However, you can also add user defined questions to each domain.

To add a user-defined signalling question

  1. Open the properties for the characteristics of included studies table.
    Click the Properties icon next to the relevant domain.

  2. Add the new signalling question.
    Click the Add button to the right of the list of user defined signalling questions for Risk of bias or to the right of the list for Concerns regarding applicability. The question will be created with the default name 'New item'.

  3. Edit 'New item' by specifying the question.

  4. Click OK.

Index Test domain

Unlike the other domains, the Index test domain is assessed for each index test or group of tests in the review. To enable assessment by test, the various index tests should have been defined under Data tables by test. You can add one or more test groups.

To add a test group

  1. Open the properties for the characteristics of included studies table.
    Click the Properties icon next to the Index Test domain.

  2. Click the Add button to the right of the list of test groups.
    A new test group with the label 'Test Group A' is created. Create the number of groups that you require (by repeatedly clicking the Add button).

  3. Modify the label of each (group of) test(s) and choose the test(s) that should be part of the group from the list of tests that appears below by ticking the box in front of each test. Also choose the studies from the list of studies that should be linked to the test group.

  4. Click OK.
    The properties window closes and the Index test domain for the test group is added to the table.

If you defined multiple test groups, there will be a domain with signalling questions for each. Note there is only one descriptive text box for all test groups.

Converting from QUADAS

The most important changes when you convert a review to QUADAS-2 are to the study characteristics, but you should also be aware that:

To convert to QUADAS-2 from QUADAS

  1. Open the properties for the methodological quality table.
    Click the Properties icon next to the 'Assessment of methodological quality table' heading.

  2. On the General tab click the button Switch to QUADAS-2.

  3. A dialogue box will appear asking you to confirm that you want to switch to QUADAS-2. The process cannot be undone so click Yes if you are sure otherwise click No.

Data is not lost during the conversion process. The old QUADAS items and the study characteristics table will be converted as shown in the tables below.

Study characteristics

RevMan 5

RevMan 5.2 – Text boxes for QUADAS-2 Domains

Study design

Patient sampling

Participants

Clinical features and setting

Both fields in merged into one called Patient characteristics and setting

Index and comparator tests

Index tests

Target condition and reference standard(s)

Target condition and reference standard(s)

Follow up

Flow and timing

User defined fields

User defined fields - separate section after the domains

Notes

Notes - separate section after the domains; if user defined Characteristics exist, the whole section  is named User defined fields

Methodological quality

QUADAS item

QUADAS-2 signalling question

QUADAS-2 Domain (Destination of old QUADAS item, author's judgement and support for judgement)

Representative spectrum?

Patient selection

Acceptable reference standard?

Reference standard

Partial verification avoided?

Flow and timing

Differential verification avoided?

Did all patients receive the same reference standard?

Incorporation avoided?

Reference standard

Reference standard results blinded?

Were the reference standard results interpreted without knowledge of the results of the index test?

Reference standard

Index test results blinded?

Were the index test results interpreted without knowledge of the results of the reference standard?

Index test

Relevant clinical information?

No related domain so added to Notes field

Uninterpretable results reported?

Flow and timing

Withdrawals explained?

Flow and timing

User defined items

Added to Notes field

References

Whiting PF, Rutjes AW, Westwood ME, Mallett S, Deeks JJ, Reitsma JB, Leeflang MM, Sterne JA, Bossuyt PM; QUADAS-2 Group. QUADAS-2: a revised tool for the quality assessment of diagnostic accuracy studies. Ann Intern Med. 2011;155(8):529-36.