Meta-analyses of trials with low and high risk of bias in the randomisation domain may yield substantially different results

2023 London

Strandell A¹, Bergh C¹, Bernhardsson S¹, Hongslo Vala C¹, Jivegård L¹, Petzold M¹, Sjögren P¹, Wallerstedt SM¹, Wartenberg C¹

¹HTA-centrum, Region Västra Götaland

Background:

Randomised controlled trials (RCTs) imply random allocation of participants to an intervention or a control group. When assessing risk of bias according to the Cochrane tool, the randomisation domain is crucial and may separate RCTs into low and high risk of bias.

Objectives:

To compare meta-analyses of RCTs with low and high risk of bias in the randomisation domain.

Methods:

A systematic review was performed within a health technology assessment (HTA) evaluating the effects of progesterone (Intervention) versus placebo (Comparison) in singleton pregnancies (Participants) regarding the Outcomes preterm birth (