Cluster Versus Individual Randomization in Prehospital, Emergency and Critical Care Trials: A Meta-Epidemiological Study
Main finding · Mortality (absolute ln(OR))Result — go to the resultMD in absolute ln(OR) −0.110 95% CI −0.093 to 0.313Authors' conclusion
A systematic difference between cRCTs and iRCTs in length-of-stay- or days-alive-type outcomes, but not mortality, was identified, with cRCTs reporting smaller effect size magnitudes than iRCTs. With under half of identified meta-analyses reporting on randomization modality, these results highlight the need for improved transparency and statistical consideration of randomization type in future meta-analyses in prehospital, emergency, and critical care.
Study context
- Population
- Meta-analyses in prehospital, emergency, or critical care within the last decade that included at least one cRCT and one iRCTn = 315,276 patients, 65 meta-analyses in quantitative analyses, 212 randomized clinical trials, cluster-randomized clinical trials (cRCTs) 39, individually randomized clinical trials (iRCTs) 173
- Participants
- 39 vs 173
- Comparison
- Deviations in effect estimates between cRCTs and iRCTs
- cRCTsn = 39
- iRCTsn = 173
- Outcome
- Mortality (absolute ln(OR))
Methodological detailssystematic literature search in PubMed and Embase, data extracted in duplicate, mixed regression models
- Systematic literature search in PubMed and Embase
- Data extracted in duplicate
- Mixed regression models
Main finding
As reported in the abstract
MD in absolute ln(OR)
−0.110
95% CI −0.093 to 0.313
Secondary outcomes
| Outcome | MD in absolute Hedges' g (95% CI) |
|---|---|
| Length-of-stay- or days-alive-type outcomes (absolute Hedges' g; secondary outcome) | −0.202 (−0.392 to −0.012) |
- Length-of-stay- or days-alive-type outcomes (absolute Hedges' g; secondary outcome): significant difference; cRCTs reporting smaller effect size magnitudes
Meta-analyses reporting on randomization type
- Eligible meta-analyses identified
- 94
- Reported on randomization type (cRCT or iRCT)
- 44.7%
Original publication
Cluster Versus Individual Randomization in Prehospital, Emergency and Critical Care Trials: A Meta-Epidemiological Study. Crit Care Med. Published 21 October 2026. doi:10.
Composed by AI from the published abstract and checked against it. How Briefs are made →