Bias Risk From Type of Consent and Time of Enrollment in Clinical Trials

Informed consent is a cornerstone in clinical research but presents a challenge in trials with medical emergencies. In this study, patients often presented with cognitive deficits and reduced capacity to give consent, and the studied interventions were time sensitive. An alternative consent model for severely affected patients is deferred consent, but this method is not approved worldwide. Many clinical trials restrict patient enrollment to daytime because of logistics. This may cause bias. In this post hoc analysis, we investigate whether type of consent and time of enrollment (regular vs off-hours) are associated with systematic differences that potentially compromise the generalizability of the results.