Development of an algorithm for choosing study designs

Article type
Authors
Peinemann F1, Kleijnen J1
1Maastricht University, The Netherlands
Abstract
Background: The purpose of systematic reviews is to answer distinct research questions on healthcare interventions. The type of study design, which is scheduled for inclusion in a systematic review, may be critical for its findings and consequences. We did not find an existing algorithm providing guidance for systematic reviewers to choose the most appropriate study designs.
Objectives: The aim of this study was to develop an algorithm that provides guidance and awareness for various design characteristics suitable to answer distinct research questions in healthcare interventions.
Methods: We addressed the following questions. What is the preferred content and format of a straightforward algorithm for integration of various study designs in a systematic review that incorporates major study characteristics as decision points and that allows consideration of practical concerns? Can the algorithm hold its promise as a useful guide for choosing appropriate study designs by testing its feasibility and applying it to existing systematic reviews?
Results: We developed an algorithm that incorporates length of follow-up (long, short) and frequency of events (rare, frequent) as binary decision points. At the end of these four pathways, each of five types of outcome (death, disease, discomfort, disability, dissatisfaction) was linked with at least one design label. The algorithm also considers practical or ethical concerns as well as unavailable best evidence, and it provides examples for explaining the critical guidance points. We confirmed the usefulness of the pathways by reproducing the study selection and its impact on the conduct of four systematic reviews.
Conclusions: The algorithm facilitates decisions about inclusion of different study types to those planning to prepare a systematic review. The algorithm cannot be applied without the consideration of disease-specific circumstances and aims of interventions. However, we think that it may reduce the time burden on review authors and may increase the scope and applicability of systematic reviews.