Ethical issues in individual-cluster trials: beyond the Ottawa Statement


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The conduct of pragmatic randomized controlled trials is increasing due to their societal importance and their role within the Patient-Centered Outcomes Research Institute (PCORI) initiative “to improve the quality and relevance of evidence available to help patients, caregivers, clinicians, employers, insurers, and policy makers make informed health decisions.” Cluster randomized trials (CRTs), in which groups rather than individuals are randomized to intervention and control conditions, naturally tend to be more pragmatic. CRTs may be categorized as “individual-cluster trials” where the intervention is delivered directly to individuals, or “cluster-cluster trials” where interventions are not divisible at the individual-level. The Ottawa Statement is the first comprehensive ethical guidance document specific to CRTs. Whereas the Ottawa Statement generally presumes that informed consent will be sought for individual-cluster trials, such trials—when used to evaluate usual care interventions—raise particular ethical issues that require further analysis and guidance. This paper has three objectives: to (1) describe current practices and reporting of ethical issues in published individual-cluster trials; (2) present an in-depth ethical analysis of an individual-cluster trial randomizing dialysis centers to two different usual care interventions; and (3) identify ethical issues that require further analysis and guidance.