Sample Size Calculations for Cluster Randomised Trials
Sample Size Calculations for Cluster Randomised Trials
复制标题
整群随机试验的样本量计算
DOI：
--
复制
发表时间：
2000
影响因子：
2.4
通讯作者：
N. Steen
中科院分区：
文献类型：
--
作者：
M. Campbell;J. Grimshaw;N. Steen
目标：整群随机试验（其中对个体进行随机分组）越来越多地应用于健康领域。采用聚类方法会对此类试验的设计产生影响，并且需要夸大样本量计算以适应聚类效应。为了进行稳健的样本量计算，需要对簇内相关系数（ICC）进行可靠的估计；然而，关于它们可能的规模以及影响其大小的因素，几乎没有经验证据。本研究的目的是对 ICC 进行实证估计并探索可能影响其大小的因素。方法：根据初级和二级护理实施研究的大量数据集，计算过程变量和患者结果的 ICC 经验估计。结果：ICC 的估计根据环境和结果类型的不同而有所不同。过程变量的 ICC 估计值高于患者结果的估计值，二级护理的估计值高于初级护理的估计值。初级保健中过程变量的 ICC 约为 0.05-0.15，而二级保健中的过程变量 ICC 约为 0.3。初级保健中患者预后的估计值普遍低于 0.05。结论：采用整群随机化对临床试验的设计、规模和分析具有影响。这项研究深入了解了初级和二级护理中 ICC 的潜在规模，并为研究人员提供了实用指南，以帮助规划该领域的未来研究。
Objectives: Cluster randomised trials, in which groups of individuals are randomised, are increasingly being used in the health field. Adopting a clustered approach has implications for the design of such trials, and sample size calculations need to be inflated to accommodate for the clustering effect. Reliable estimates of intracluster correlation coefficients (ICCs) are required for robust sample size calculations to be made; however, little empirical evidence is available on their likely size, and on factors which influence their magnitude. The aim of this study was to generate empirical estimates of ICCs and to explore factors which may affect their magnitude. Methods: Empirical estimates of ICCs were calculated for both process variables and patient outcomes from a number of datasets of primary and secondary care implementation studies. Results: Estimates of ICCs varied according to setting and type of outcome. Estimates of ICCs for process variables were higher than those for patient outcomes, and estimates derived from secondary care were higher than those from primary care. ICCs for process variables in primary care were of the order of 0.05–0.15, whilst those in secondary care were of the order of 0.3. Estimates for patient outcomes in primary care were generally lower than 0.05. Conclusions: Adopting cluster randomisation has implications for the design, size and analysis of clinical trials. This study gives an insight into the potential size of ICCs in primary and secondary care, and provides a practical guide to researchers to aid the planning of future studies in this area.