Background: the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) Statement was published in 2009 and designed to help authors of systematic reviews (SRs) prepare a transparent report of their review. Authors and journals have widely adopted PRISMA, as evidenced by its 40,000 citations and endorsement from over 400 journals. We decided that the checklist needed revisions to address various advances in SR methodology and publication practices, and to rearrange the layout and rephrase existing items to increase clarity.
Objectives: to update the PRISMA 2009 statement for reporting SRs and meta-analyses.
Methods: we conducted a selective review of 55 documents providing reporting guidance for SRs, to generate ideas for how to modify the PRISMA 2009 statement. We recruited 110 SR methodologists, authors and journal editors to complete a survey to provide feedback on suggested modifications arising from the literature review. The results of these projects were discussed at a 22-member expert panel meeting in September 2018. Following the meeting, a draft of the PRISMA 2019 checklist was generated and refined iteratively based on feedback from the PRISMA Group members and piloting with authors and journal editors.
Results: the PRISMA 2019 statement consists of updated guidance intended to facilitate transparent reporting of SRs and meta-analyses. Nearly all PRISMA 2009 checklist items were modified in some way (e.g. disaggregated into multiple subitems to facilitate clarity, rephrased to reflect changes in terminology). The statement also includes new reporting guidance to reflect advances in methods to identify, select, appraise and synthesise studies, and to enhance the reproducibility and openness of SRs. The checklist is accompanied by a revised Explanation and Elaboration document with updated reporting exemplars, and a revised PRISMA flow diagram.
Conclusions: we anticipate that the PRISMA 2019 statement will benefit researchers, editors, peer reviewers, guideline developers and policymakers involved in conducting or using SRs and meta-analyses. Ultimately, we hope that uptake of the guidance will lead to more transparent reporting of SRs, so facilitating decision making in the development of evidence-based guidance for clinical practice and health policy.