Statistical Power and Sample Size Requirements for Three Level Hierarchical Cluster Randomized Trials
Statistical Power and Sample Size Requirements for Three Level Hierarchical Cluster Randomized Trials
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DOI：
10.1111/j.1541-0420.2008.00993.x
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发表时间：
2008-12-01
期刊：
影响因子：
1.9
通讯作者：
Leon, Andrew C.
中科院分区：
文献类型：
--
作者：
Heo, Moonseong;Leon, Andrew C.
集群随机临床试验（Cluster - rct），其中社区实体作为集群，通常产生具有三个层次的数据。例如，干预措施被随机分配到集群（三级单元）。同一组内的卫生保健专业人员（二级单位）接受随机分配的干预措施培训，为受试者提供护理（一级单位）。在这项研究中，我们导出了一个封闭形式的幂函数和公式，以确定在受试者水平上检测干预对结果的影响所需的样本量。在这样做的过程中，我们使用了基于最大似然估计的检验统计量，该估计来自三水平数据的混合效应线性回归模型。仿真研究随后验证了基于推导公式的理论功率估计与基于模拟数据的经验估计几乎相同。讨论了集群随机对照试验设计阶段的建议。
Cluster randomized clinical trials (cluster-RCT), where the community entities serve as clusters, often yield data with three hierarchy levels. For example, interventions are randomly assigned to the clusters (level three unit). Health care professionals (level two unit) within the same cluster are trained with the randomly assigned intervention to provide care to subjects (level one unit). In this study, we derived a closed form power function and formulae for sample size determination required to detect an intervention effect on outcomes at the subject's level. In doing so, we used a test statistic based on maximum likelihood estimates from a mixed-effects linear regression model for three level data. A simulation study follows and verifies that theoretical power estimates based on the derived formulae are nearly identical to empirical estimates based on simulated data. Recommendations at the design stage of a cluster-RCT are discussed.