Comparing multiple treatments: an introduction to overviews of reviews

Tags: Workshop
Hartling L1, Fernandes R1, Becker L2, Foisy M3
1Child Health Field, 2Comparing Multiple Interventions Methods Group; Cochrane Innovations, United States, 3Alberta Research Center for Health Evidence, University of Alberta, Canada

Objectives:

1. Introduce overviews of reviews.

2. Discuss points to consider when choosing whether to do an overview or an intervention review.

3. Provide general guidance on the steps for conducting an overview.

Description: Overviews integrate information from multiple systematic reviews to provide a single synthesis of relevant evidence, e.g. multiple interventions for a single health condition. Overviews follow steps similar to systematic reviews in terms of searching, study selection, quality assessment, and data extraction except that the unit of analysis is the systematic review rather than the primary study. The approach to data analysis typically focuses on the analyses conducted within the relevant systematic reviews, with a narrative synthesis of results across reviews. While readers may draw inferences regarding comparative effectiveness, overviews typically do not conduct formal statistical analyses (e.g. network meta-analysis) when data from direct comparisons is not available. This workshop will focus on overviews with systematic reviews as the unit of analysis and non-statistical synthesis. We will introduce the concept of indirect comparisons and how to decide whether an overview or intervention review is most appropriate. We will discuss methodological considerations when undertaking an overview. We will encourage participants to share their experiences and perspectives on this rapidly developing methodology.