A new article published this week in JAMA describes the cluster randomized trial design. The article is part of JAMA’s Guide to Statistics and Methods series, which publishes explanations of analytic and methodologic approaches used in current research articles to help clinicians better understand the research.
In “Cluster Randomized Trials: Evaluating Treatments Applied to Groups,” Drs. William J. Meurer and Roger J. Lewis define cluster randomization, describe its advantages and limitations, and provide guidance on interpreting cluster randomized trials. The article discusses aspects of a recent cluster randomized trial, the RESTORE trial, as an example.
In RESTORE, pediatric intensive care units were randomized to assess the effects of a nurse-implemented sedation protocol for children with acute respiratory failure on mechanical ventilation. As Meurer and Lewis point out, “interventions that involve training multidisciplinary health care teams are practically difficult to conduct using individual-level randomization, as health care practitioners cannot easily unlearn a new way of taking care of patients.” Cluster randomized designs are therefore often used for this type of research, and it is important for clinicians to be able to understand and evaluate these studies.
Reference: Meurer WJ, Lewis RJ. Cluster randomized trials: evaluating treatments applied to groups. JAMA. 2015;313:2068-2069. PMID: 26010636. doi:10.1001/jama.2015.5199.