Dynamic balancing randomization in controlled clinical trials
Dynamic balancing randomization in controlled clinical trials
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DOI：
10.1002/sim.2421
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发表时间：
2005-12-30
影响因子：
2
通讯作者：
Pillai, A
中科院分区：
文献类型：
--
作者：
Heritier, S;Gebski, V;Pillai, A
在随机临床试验的设计中，在重要预后因素（分层）之间平衡治疗分配可以提高最终比较的效率。虽然存在随机化方法，试图平衡各层的处理（排列块，最小化，有偏差的硬币），但这些方法对所有层都具有同等的重要性。动态平衡随机化（Dynamic balancing randomization， DBR）是Signorini等人提出的一种基于树的方法，允许在不同的层中存在不同程度的不平衡，在保证每一级预后风险因素（conditional balance）的平衡的同时保持随机性。我们提出了对原始方法的简单修改，以保持重要地层的边际平衡，并研究了这种修改的性质。两个重要的性能指标用于提供方法之间的比较：损失函数，可以解释为不平衡向量的平方范数，以及传达随机性程度的强制指数。通过两次模拟试验，对最小化DBR和有偏差硬币设计DBR进行了比较。版权所有(c) 2005 John Wiley & Sons, Ltd。
In the design of randomized clinical trials, balancing of treatment allocation across important prognostic factors (strata) improves the efficiency of the final comparisons. Whilst randomization methods exist which attempt to balance treatments across the strata (permuted blocks, minimization, biased coin) these approaches assign equal importance for all the strata. Dynamic balancing randomization (DBR) is a tree-based method proposed by Signorini et al. allowing different levels of imbalance in different strata which ensures a balance for each level of prognostic risk factors (conditional balance) whilst at the same time preserving randomness. We present a simple modification to the original approach to maintain a marginal balance over important strata and examine the properties of this modification. Two important measures of performance are used to provide comparisons between the approaches: a loss function, which can be interpreted as the squared norm of the imbalance vector, and a forcing index which conveys the degree of randomness. A comparison of DBR with minimization and a biased coin design is carried out by simulation on two simulated trials. Copyright (c) 2005 John Wiley & Sons, Ltd.