Table 1

Preferred reporting items for systematic review and meta-analysis protocols checklist16

Section and topicItem noChecklist itemAddressed in page
Administrative information
  Identification1aIdentify the report as a protocol of a systematic review1
  Update1bIf the protocol is for an update of a previous systematic review, identify as suchNA
 Registration2If registered, provide the name of the registry (such as PROSPERO) and registration number3, 12
  Contact3aProvide name, institutional affiliation, email address of all protocol authors; provide physical mailing address of corresponding author1
  Contributions3bDescribe contributions of protocol authors and identify the guarantor of the review1, 15
 Amendments4If 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 amendmentsNA
  Sources5aIndicate sources of financial or other support for the review15
  Sponsor5bProvide name for the review funder and/or sponsor15
  Role of sponsor or funder5cDescribe roles of funder(s), sponsor(s), and/or institution(s), if any, in developing the protocol15
 Rationale6Describe the rationale for the review in the context of what is already known4–5
 Objectives7Provide an explicit statement of the question(s) the review will address with reference to participants, interventions, comparators and outcomes (PICO)5–6
 Eligibility criteria8Specify 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 review6–7
 Information sources9Describe all intended information sources (such as electronic databases, contact with study authors, trial registers or other grey literature sources) with planned dates of coverage6
 Search strategy10Present draft of search strategy to be used for at least one electronic database, including planned limits, such that it could be repeated6 & box 1
 Study records
  Data management11aDescribe the mechanism(s) that will be used to manage records and data throughout the review7–8
  Selection process11bState 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)8
  Data collection process11 cDescribe planned method of extracting data from reports (such as piloting forms, done independently, in duplicate), any processes for obtaining and confirming data from investigators8–9
 Data items12List and define all variables for which data will be sought (such as PICO items, funding sources), any preplanned data assumptions and simplifications8–9
 Outcomes and prioritisation13List and define all outcomes for which data will be sought, including prioritisation of main and additional outcomes, with rationale7
 Risk of bias in individual studies14Describe 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 synthesis9–10
 Data synthesis15aDescribe criteria under which study data will be quantitatively synthesised10
15bIf 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 I,2 Kendall’s τ)10–11
15 cDescribe any proposed additional analyses (such as sensitivity or subgroup analyses, metaregression)11
15dIf quantitative synthesis is not appropriate, describe the type of summary plannedNA
 Metabias(es)16Specify any planned assessment of meta-bias(es) (such as publication bias across studies, selective reporting within studies)11
 Confidence in cumulative evidence17Describe how the strength of the body of evidence will be assessed9–10
  • NA, not applicable; PICO, participants, interventions, comparators and outcomes; PROSPERO, International Prospective Register of Systematic Reviews.