Université de Tours, Université de Nantes, INSERM, SPHERE U1246, Tours, France; INSERM CIC1415, CHRU de Tours, Tours, France.
Departments of Medicine, Epidemiology & Biostatistics, and Philosophy, Western University, 1151 Richmond Street, London, ON N6A 5B7, Canada.
J Epidemiol Popul Health. 2024 Feb;72(1):202197. doi: 10.1016/j.jeph.2024.202197. Epub 2024 Feb 9.
A cluster randomized trial is defined as a randomized trial in which intact social units of individuals are randomized rather than individuals themselves. Outcomes are observed on individual participants within clusters (such as patients). Such a design allows assessing interventions targeting cluster-level participants (such as physicians), individual participants or both. Indeed, many interventions assessed in cluster randomized trials are actually complex ones, with distinct components targeting different levels. For a cluster-level intervention, cluster randomization is an obvious choice: the intervention is not divisible at the individual-level. For individual-level interventions, cluster randomization may nevertheless be suitable to prevent group contamination, for logistical reasons, to enhance participants' adherence, or when objectives pertain to the cluster level. An unacceptable reason for cluster randomization would be to avoid obtaining individual consent. Indeed, participants in cluster randomized trials have to be protected as in any type of trial design. Participants may be people from whom data are collected, but they may also be people who are intervened upon, and this includes both patients and physicians (for example, physicians receiving training interventions). Consent should be sought as soon as possible, although there may exist situations where participants may consent only for data collection, not for being exposed to the intervention (because, for instance, they cannot opt-out). There may even be situations where participants are not able to consent at all. In this latter situation a waiver of consent must be granted by a research ethics committee.
一项整群随机试验被定义为一种将完整的个体社会单位进行随机分组而不是将个体本身进行随机分组的随机试验。在整群（如患者）中观察个体参与者的结果。这种设计允许评估针对群体参与者（如医生）、个体参与者或两者的干预措施。实际上，许多在整群随机试验中评估的干预措施实际上是复杂的，具有针对不同层次的不同组成部分。对于群体层面的干预措施，整群随机分组是一个明显的选择：干预措施在个体层面上不可分割。对于个体层面的干预措施，出于后勤原因、提高参与者的依从性，或者当目标涉及群体层面时，整群随机分组可能仍然适用，以防止群体污染。选择整群随机分组的一个不可接受的理由是为了避免获得个体同意。实际上，在任何类型的试验设计中，都必须保护参与整群随机试验的参与者。参与者可能是从其收集数据的人，但他们也可能是接受干预的人，这包括患者和医生（例如，接受培训干预的医生）。应尽快寻求同意，尽管可能存在参与者仅同意数据收集而不同意接受干预的情况（因为例如，他们不能选择退出）。甚至可能存在参与者根本无法同意的情况。在后一种情况下，研究伦理委员会必须批准同意豁免。
