Elley C Raina, Kerse Ngaire, Chondros Patty, Robinson Elizabeth
Department of General Practice, Wellington School of Medicine, University of Otago, New Zealand.
Aust N Z J Public Health. 2005 Oct;29(5):461-7. doi: 10.1111/j.1467-842x.2005.tb00227.x.
This paper provides intraclass correlation coefficients (ICCs) for estimation of sample size inflation required in future cluster randomised trials in primary or residential care.
Three cluster randomised trials were conducted among middle-aged and older adults in primary care and residential care in Australia and New Zealand between 1995 and 2002. Baseline means or proportions, mean change, and ICCs with their standard errors and 95% confidence intervals are reported for outcome variables used in the three studies. The ICCs were estimated from a one-way random effects model using the analysis of variance method.
ICCs for quality of life and psychological variables in the primary care studies were low (below 0.018). ICCs for clinical and physical activity variables ranged from 0 to 0.08. ICCs for health and functional status in residential care for the elderly were high, ranging from 0.025 to 0.514.
The magnitude of the intraclass correlation varies with the venue of the trial, the outcome variables used, and the expected effect of the intervention. However, the intraclass correlations provided will be useful for more appropriate planning of residential and primary care-based trials in the future.
本文提供组内相关系数（ICCs），用于估计未来在初级或住院护理中进行整群随机试验所需的样本量膨胀情况。
1995年至2002年期间，在澳大利亚和新西兰对初级护理和住院护理中的中年及老年人进行了三项整群随机试验。报告了三项研究中使用的结局变量的基线均值或比例、平均变化以及组内相关系数及其标准误和95%置信区间。组内相关系数采用方差分析法从单向随机效应模型中估计得出。
初级护理研究中生活质量和心理变量的组内相关系数较低（低于0.018）。临床和身体活动变量的组内相关系数范围为0至0.08。老年住院护理中健康和功能状态的组内相关系数较高，范围为0.025至0.514。
组内相关系数的大小因试验场所、所使用的结局变量以及干预的预期效果而异。然而，所提供的组内相关系数将有助于未来更合理地规划基于住院护理和初级护理的试验。
