Journal Article

GRADE guidance 24 optimizing the integration of randomized and non-randomized studies of interventions in evidence syntheses and health guidelines

Regidor, Deborah L., Guyatt, Gordon, Murad, Mohammad H., Verbeek, Jos, Alexander, Paul Elias, Cuello-Garcia, Carlos A., Katikireddi, Srinivasa Vittal, Falavigna, Maicon, Thayer, Kris, Santesso, Nancy, Ansari, Mohammed T., Brozek, Jan L., Meerpohl, Joerg, Reeves, Barnaby, Akl, Elie A., Schwingshackl, Lukas, Schünemann, Holger J., Morgan, Rebecca L., Mustafa, Reem, Garner, Paul

2022

Overview

•Randomized controlled trials (RCTs) provide the best source of evidence for research syntheses estimating relative effects of an intervention.•Non-randomized studies of representative populations can provide the best evidence with respect to prognosis, baseline risk, test accuracy, and estimates of utility and values and preferences of different outcomes.•For many research questions randomized trials will be scarce or unavailable, and decision-makers might need to consider using non-randomized (observational) studies that can provide evidence about the effectiveness of interventions as replacement (in the absence of appropriate RCT evidence), sequential, or complementary to RCT evidence•GRADE guidance can help authors that are considering the inclusion of non-randomized studies in addition to RCTs during the evidence synthesis process. This is the 24th in the ongoing series of articles describing the GRADE approach for assessing the certainty of a body of evidence in systematic reviews and health technology assessments and how to move from evidence to recommendations in guidelines. Guideline developers and authors of systematic reviews and other evidence syntheses use randomized controlled studies (RCTs) and non-randomized studies of interventions (NRSI) as sources of evidence for questions about health interventions. RCTs with low risk of bias are the most trustworthy source of evidence for estimating relative effects of interventions because of protection against confounding and other biases. However, in several instances, NRSI can still provide valuable information as complementary, sequential, or replacement evidence for RCTs. In this article we offer guidance on the decision regarding when to search for and include either or both types of studies in systematic reviews to inform health recommendations. This work aims to help methodologists in review teams, technology assessors, guideline panelists, and anyone conducting evidence syntheses using GRADE.

• Publisher: Elsevier Inc,Elsevier Limited,Elsevier
• Subject: Bias / Certainty of evidence / Decision making / Epidemiology / Estimates / GRADE / GRADE series / Guidelines / Health promotion / Humans / Internal Medicine / Intervention / Literature reviews / Non-randomized studies / Quality of evidence / Research Design / Risk of bias / ROBINS / Systematic review / Systematic Reviews as Topic / Technology assessment / Technology Assessment, Biomedical / Working groups