The role and challenges of cluster randomised trials for global health

Abstract

Evaluating whether an intervention works when trialled in groups of individuals can pose complex challenges for clinical research. Cluster randomised controlled trials involve the random allocation of groups or clusters of individuals to receive an intervention, and they are commonly used in global health research. In this paper, we describe the potential reasons for the increasing popularity of cluster trials in low-income and middle-income countries. We also draw on key areas of global health research for an assessment of common trial planning practices, and we address their methodological shortcomings and pitfalls. Lastly, we discuss alternative approaches for population-level intervention trials that could be useful for research undertaken in low-income and middle-income countries for situations in which the use of cluster randomisation might not be appropriate.

Rethinking the efficacy of awake prone positioning in COVID-19-related acute hypoxaemic respiratory failure

“…In contrast to individual RCTs, in which individual participants are randomly assigned to a group, cluster RCTs are designed to evaluate interventions delivered at the group level. 2 This design increases the possibility of some types of bias, such as identification or recruitment bias and loss of clusters. 2 Therefore, the Cochrane collaboration recommends a specific tool, the risk-of-bias 2.0 for cluster-randomised trials tool for assessing the risk of bias in cluster RCTs.…”

Study protocol for a cluster randomised trial of sterile glove and instrument change at the time of wound closure to reduce surgical site infection in low- and middle-income countries (CHEETAH)

“…Cluster randomised trials are common in global health but rare for evaluation of intraoperative interventions [ 31 ]. One prominent example of an in-theatre intervention applied at a cluster level was the World Health Organization Surgical Safety Checklist [ 18 ].…”

Effectiveness and safety of reactive focal mass drug administration (rfMDA) using dihydroartemisinin–piperaquine to reduce malaria transmission in the very low-endemic setting of Eswatini: a pragmatic cluster randomised controlled trial

“…Covariate constrained randomisation may have been more effective at achieving baseline balance than stratified randomisation. 35 When outcomes are rare and clustered, trials require very large cluster numbers to have sufficient statistical power and baseline balance. 36 37 Future trials of infectious disease interventions in very low transmission settings with strong spatiotemporal clustering may benefit from ring designs, which randomise the group of individuals in proximity to index cases at the time of index case detection rather than randomising fixed geographical areas at baseline.…”