Randomization methods in emergency setting trials: a descriptive review.

Area of Science:

• Clinical Trials Methodology
• Emergency Medicine Research
• Biostatistics

Background:

• Quasi-randomization methods may accelerate participant recruitment in emergency care settings.
• However, concerns exist regarding potential selection bias introduced by quasi-randomization.

Purpose of the Study:

• To assess whether quasi-randomization is associated with a higher incidence of selection bias compared to true randomization in emergency care trials.
• To evaluate baseline imbalances in prognostic indicators between treatment groups in randomized versus quasi-randomized trials.

Main Methods:

• Systematic search of Cochrane Library and other databases for systematic reviews of interventions in emergency or urgent care.
• Assessment of selection bias, defined as baseline imbalances in prognostic indicators, in trials employing true randomization versus quasi-randomization.

Main Results:

• Analysis included 16 truly randomized and 11 quasi-randomized trials across seven reviews.
• Baseline imbalance occurred in 25% of true randomization trials and 18% of quasi-randomization trials.
• Adequate treatment allocation concealment was noted in three of the four truly randomized trials with baseline imbalance.

Conclusions:

• No strong evidence suggests quasi-randomization is more frequently associated with selection bias than true randomization.
• High risk of bias judgments for quasi-randomized emergency studies should not be presumed in systematic reviews.
• Clinical heterogeneity and limited accrual data precluded exploration of recruitment rate differences or population representativeness between randomization methods.