Guidance for overviews of reviews continues to accumulate, but important challenges remain: A scoping review

Abstract

Background. Overviews of reviews (overviews) provide an invaluable resource for healthcare decision-making by combining large volumes of systematic review (SR) data into a single synthesis. The production of high-quality overviews hinges on the availability of practical evidence-based guidance for conduct and reporting.Objectives. Within the broad purpose of informing the development of a reporting guideline for overviews, we aimed to provide an up-to-date map of existing guidance related to the conduct of overviews, and to identify common challenges that authors face when undertaking overviews.Methods. We updated a scoping review published in 2016 using the search methods that had produced the highest yield: ongoing reference tracking (2014 to March 2020 in Pubmed, Scopus, and Google Scholar), hand-searching conference proceedings and websites, and contacting authors of published overviews. Using a qualitative meta-summary approach, one reviewer extracted, organized, and summarized the guidance and challenges presented within the included documents. A second reviewer verified the data and synthesis.Results. We located 28 new guidance documents, for a total of 77 documents produced by 34 research groups. The new guidance helps to resolve some earlier identified challenges in the production of overviews. Important developments include strengthened guidance on handling primary study overlap at the study selection and analysis stages. Despite marked progress, several areas continue to be hampered by inconsistent or lacking guidance. There is ongoing debate about whether, when, and how supplemental primary studies should be included in overviews. Guidance remains scant on how to extract and use appraisals of quality of the primary studies within the included SRs and how to adapt GRADE methodology to overviews. The challenges that overview authors face are often related to the above-described steps in the process where evidence-based guidance is lacking or conflicting.Conclusion. The rising popularity of overviews has been accompanied by a steady accumulation of new, and sometimes conflicting, guidance. While recent guidance has helped to address some of the challenges that overview authors face, areas of uncertainty remain. Practical tools supported by empirical evidence are needed to assist authors with the many methodological decision points that are encountered in the production of overviews.

Graphical Representation of Overlap for OVErviews: GROOVE tool

“…There are several ways to deal with overlap at different stages during the development of the overview. [8][9][10][11] Overview authors may decide about eligibility, data extraction, risk of bias assessment and synthesis/ presentation of the results, based on the overlap of primary studies among the included SRs. Indeed, a variety of tools has been proposed for guiding these decisions.…”

Reporting guideline for overviews of reviews of healthcare interventions: The Preferred Reporting Items for Overviews of Reviews (PRIOR) statement

“…This was supplemented by a study examining the completeness of reporting in a random sample of more contemporary overviews (published between January 2015 and March 2017) (18). The second was a scoping review of methodological guidance and author-reported challenges related to conducting overviews of reviews (14). We continued to monitor article alerts (i.e., Google Scholar, Scopus Citing References, and PubMed Similar Articles) until publication of the reporting guideline to keep apprised of new developments that could impact its content.…”

“…The PRIOR statement is intended for overviews of reviews of healthcare interventions and may not be applicable to other fields and/or other types of overviews of reviews (e.g., qualitative, diagnostic accuracy). The guideline is based on currently available evidence regarding the reporting of published overviews (30), a scoping review of currently available methodological guidance (14), and other recent evidence maps regarding the methods used in overviews of reviews (15,16). We acknowledge that for some items, there is little or no methodological guidance available for overview of reviews authors (e.g., the adaptation of GRADE to overviews, the assessment of missing results in a synthesis), and that in time PRIOR will require an update.…”

“…In a recent survey, Bougioukas et al (2021) identified 1,558 overviews of reviews published in English between 2000 and 2020, with 57% (n=882) being published in the last four years (2017 to 2020) (8). Alongside their growing popularity as a publication type, guidance for the conduct of overviews of reviews has become abundant (14)(15)(16). Although many of the methods used to undertake systematic reviews are suitable for overviews of reviews, they also present unique methodological challenges (11,(15)(16)(17).…”

“…Although many of the methods used to undertake systematic reviews are suitable for overviews of reviews, they also present unique methodological challenges (11,(15)(16)(17). New methodological guidance published in recent years has helped to resolve some common challenges (e.g., selecting systematic reviews for inclusion; handling primary study overlap at the analysis stage); however, several areas continue to be characterized by inconsistent or insufficient guidance (14)(15)(16). The lack of consensus on some of the methodologies applied in overviews of reviews means that careful reporting is required.…”