Sample size determination for GEE analyses of stepped wedge cluster randomized trials
Sample size determination for GEE analyses of stepped wedge cluster randomized trials
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DOI：
10.1111/biom.12918
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发表时间：
2018-12-01
期刊：
影响因子：
1.9
通讯作者：
Preisser, John S.
中科院分区：
文献类型：
--
作者：
Li, Fan;Turner, Elizabeth L.;Preisser, John S.
在阶梯楔形随机试验中，完整的个体群从随机分配的时期开始从控制切换到干预。这种试验在卫生服务研究中越来越受欢迎。当从每个聚类中招募一个封闭队列进行纵向随访时，适当的样本量计算应考虑三种不同类型的组内相关性：期内相关性、期间相关性和个体内相关性。将后两个相关参数设置为相等可适应横截面设计。我们提出的样本量程序的框架内的连续和二进制响应的广义估计方程，采用块交换内集群相关结构定义的不同的相关类型。对于连续响应，我们表明，组内相关性影响功率仅通过两个特征值的相关矩阵。我们表明，分析能力与模拟功率少至8个集群，当数据进行分析时，使用偏差校正的估计方程的相关参数同时与偏差校正的三明治方差估计。
In stepped wedge cluster randomized trials, intact clusters of individuals switch from control to intervention from a randomly assigned period onwards. Such trials are becoming increasingly popular in health services research. When a closed cohort is recruited from each cluster for longitudinal follow-up, proper sample size calculation should account for three distinct types of intraclass correlations: the within-period, the inter-period, and the within-individual correlations. Setting the latter two correlation parameters to be equal accommodates cross-sectional designs. We propose sample size procedures for continuous and binary responses within the framework of generalized estimating equations that employ a block exchangeable within-cluster correlation structure defined from the distinct correlation types. For continuous responses, we show that the intraclass correlations affect power only through two eigenvalues of the correlation matrix. We demonstrate that analytical power agrees well with simulated power for as few as eight clusters, when data are analyzed using bias-corrected estimating equations for the correlation parameters concurrently with a bias-corrected sandwich variance estimator.