Integrating evidence: existing systematic reviews and primary studies

Article type
Authors
Robinson K1, Chou R2, Berkman N3, Newberry S4, Fu R5, Harling L6, Dryden D6, Butler M7, Foisy M8, Anderson J9, Motu'apuaka M9, Revelo R9, Guise J9, Chang S10
1Johns Hopkins University EPC, USA
2Pacific Northwest EPC, USA
3RTI International, USA
4Southern California EPC, RAND, USA
5Portland VA Research Foundation, USA
6Department of Pediatrics, University of Alberta, Canada
7Minnesota EPC, USA
8Department of Pediatrics, University of Alberta, USA
9Scientific Resource Center for the AHRQ Effective Health Care Program, USA
10Center for Evidence and Practice Improvment, Agency for Healthcare Research and Quality, USA
Abstract
Background: The exponential growth in the number of systematic reviews (SRs) being published, the need to regularly update existing reviews, along with the time and resources required to undertake a review, motivates the desire to integrate existing reviews into a new review. However, there is a trade-off between accepting the results of a prior review and redoing selected elements, or the review in its entirety.
Objectives: The goal of this systematic review methods development project was to enhance guidance on approaches and considerations for integrating existing SRs into new reviews.
Methods: Over a two-year period, a workgroup of SR methodologists from across the US Agency for Healthcare Research and Quality (AHRQ) Evidence-based Practice Centers (EPCs) clarified guidance needs and developed new recommendations. Deliberations were supported by a review of guidance developed by the EPCs and eight other organizations, including Cochrane and the National Institute for Health and Care Excellence (NICE ); interviews with key informants from organizations that conduct or use SRs; and a search of the literature. Recommendations were developed in an iterative manner and based on consensus of workgroup members.
Results: In Year 1, the workgroup found general consensus across organizations for assessing the relevance of prior reviews and scanning their references to identify studies for a new review. In Year 2, the workgroup identified eight areas where additional guidance was needed. No literature relevant to informing discussions was identified.
Recommendations were developed concerning: minimum eligibility criteria for including an existing review based on its approach and methodological rigor; criteria for using risk of bias assessments from an earlier review; presenting findings from the earlier review distinctly from new studies and synthesizing the two; and an approach for strength of evidence.
Conclusions: Preliminary guidance was developed promoting an efficient and unbiased approach for integrating old and new evidence.