Table 1 PRISMA-P checklist for protocol items

Title:

 Identification

1a

Identify the report as a protocol of a systematic review

1

Title

 Update

1b

If the protocol is for an update of a previous systematic review, identify as such

N/A

N/A

Registration

2

If registered, provide the name of the registry (such as PROSPERO) and registration number

2

22

Authors:

 Contact

3a

Provide name, institutional affiliation, e-mail address of all protocol authors; provide physical mailing address of corresponding author

1

-

 Contributions

3b

Describe contributions of protocol authors and identify the guarantor of the review

11

209–219

Amendments

4

If the protocol represents an amendment of a previously completed or published protocol, identify as such and list changes; otherwise, state plan for documenting important protocol amendments

N/A

N/A

Support:

 Sources

5a

Indicate sources of financial or other support for the review

11

208

 Sponsor

5b

Provide name for the review funder and/or sponsor

11

208

 Role of sponsor or funder

5c

Describe roles of funder(s), sponsor(s), and/or institution(s), if any, in developing the protocol

N/A

N/A

Rationale

6

Describe the rationale for the review in the context of what is already known

3–4

24–55

Objectives

7

Provide an explicit statement of the question(s) the review will address with reference to participants, interventions, comparators, and outcomes (PICO)

4

56–63

Eligibility criteria

8

Specify the study characteristics (such as PICO, study design, setting, time frame) and report characteristics (such as years considered, language, publication status) to be used as criteria for eligibility for the review

4

56–58

4–5

69–91

Information sources

9

Describe all intended information sources (such as electronic databases, contact with study authors, trial registers or other grey literature sources) with planned dates of coverage

6

92–114

Search strategy

10

Present draft of search strategy to be used for at least one electronic database, including planned limits, such that it could be repeated

Table 2

Table 2

Study records:

 Data management

11a

Describe the mechanism(s) that will be used to manage records and data throughout the review

7

116–117

 Selection process

11b

State the process that will be used for selecting studies (such as two independent reviewers) through each phase of the review (that is, screening, eligibility and inclusion in meta-analysis)

7

119–126

 Data collection process

11c

Describe planned method of extracting data from reports (such as piloting forms, done independently, in duplicate), any processes for obtaining and confirming data from investigators

7

120–121

9

163–170

Data items

12

List and define all variables for which data will be sought (such as PICO items, funding sources), any pre-planned data assumptions and simplifications

7

127–134

Outcomes and prioritization

13

List and define all outcomes for which data will be sought, including prioritization of main and additional outcomes, with rationale

8

138–141

Risk of bias in individual studies

14

Describe anticipated methods for assessing risk of bias of individual studies, including whether this will be done at the outcome or study level, or both; state how this information will be used in data synthesis

8–9

153–169

Data synthesis

15a

Describe criteria under which study data will be quantitatively synthesised

9

171–188

15b

If data are appropriate for quantitative synthesis, describe planned summary measures, methods of handling data and methods of combining data from studies, including any planned exploration of consistency (such as I², Kendall’s τ)

9

171–188

15c

Describe any proposed additional analyses (such as sensitivity or subgroup analyses, meta-regression)

N/A

N/A

15d

If quantitative synthesis is not appropriate, describe the type of summary planned

10

184–188

Meta-bias(es)

16

Specify any planned assessment of meta-bias(es) (such as publication bias across studies, selective reporting within studies)

NA

NA

Confidence in cumulative evidence

17

Describe how the strength of the body of evidence will be assessed (such as GRADE)

9

178–179