GRADE Guidelines: 18. How ROBINS-I and other tools to assess risk of bias in nonrandomized studies should be used to rate the certainty of a body of evidence

Abstract

To provide guidance on how systematic review authors, guideline developers, and health technology assessment practitioners should approach the use of the risk of bias in non-randomized studies of interventions (ROBINS-I) tool as part of GRADE's certainty rating process. Iterative discussions, testing in systematic reviews, presentation at GRADE working group meetings with feedback from the GRADE Working Group. We describe where to start the initial assessment of a body of evidence with the use of ROBINS-I, and where one would anticipate the final rating would end up. GRADE accounted for issues that mitigate concerns about confounding and selection bias by introducing the upgrading domains: large effects, dose-effect relations, and when plausible residual confounders or other biases increase certainty. They will need to be considered in an assessment of a body of evidence when using ROBINS-I. The use of ROBINS-I in GRADE assessments may allow for a better comparison of evidence from RCTs and NRS because they are placed on a common metric for risk of bias. Challenges remain that include appropriate presentation of evidence from RCTs and NRS for decision-making and how to optimally integrate RCTs and NRS in an evidence assessment