Cluster randomized trials of individual-level interventions were at high risk of bias.
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ABSTRACT: Objectives
To describe the prevalence of risks of bias in cluster-randomized trials of individual-level interventions, according to the Cochrane Risk of Bias tool.Study design and setting
Review undertaken in duplicate of a random sample of 40 primary reports of cluster-randomized trials of individual-level interventions.Results
The most common reported reasons for adopting cluster randomization were the need to avoid contamination (17, 42.5%) and practical considerations (14, 35%). Of the 40 trials all but one was assessed as being at risk of bias. A majority (27, 67.5%) were assessed as at risk due to the timing of identification and recruitment of participants; many (21, 52.5%) due to an apparent lack of adequate allocation concealment; and many due to selectively reported results (22, 55%), arising from a mixture of reasons including lack of documentation of primary outcome. Other risks mostly occurred infrequently.Conclusion
Many cluster-randomized trials evaluating individual-level interventions appear to be at risk of bias, mostly due to identification and recruitment biases. We recommend that investigators carefully consider the need for cluster randomization; follow recommended procedures to mitigate risks of identification and recruitment bias; and adhere to good reporting practices including clear documentation of primary outcome and allocation concealment methods.
SUBMITTER: Easter C
PROVIDER: S-EPMC8592576 | biostudies-literature |
REPOSITORIES: biostudies-literature
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