A comparison of urn designs for randomized clinical trials of K > 2 treatments.
A comparison of urn designs for randomized clinical trials of K > 2 treatments.
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DOI：
10.1081/bip-100101016
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发表时间：
2000-02-01
影响因子：
1.1
通讯作者：
Rosenberger, W F
中科院分区：
文献类型：
--
作者：
Ivanova, A;Rosenberger, W F
临床试验中的反应适应性设计涉及将从患者对治疗的反应中积累的信息纳入随机化方案，以便将更多的患者分配到到那时为止在试验中表现更好的治疗。在生成自适应随机化方案中有用的一个概率模型是URN模型。我们将简要概述这些自适应模型，并对其中的四个模型进行比较。我们将感兴趣的是，这四种模型如何在二分反应治疗的临床试验中将治疗失败的数量降至最低。比较将通过四个处理的模拟和三个中等样本大小的处理的模拟来完成。我们在假设治疗的结果是立即知道的情况下比较设计，并且我们也允许延迟响应。对各种替代方案下的功率进行了分析。我们的结果表明，有移民的出生和死亡骨灰盒是最好的，除非成功概率非常小，在这种情况下，波利亚骨灰盒的随机版本是首选的。
Response-adaptive designs in clinical trials involve incorporating accruing information from patient responses to treatment into the randomization scheme in order to assign more patients to the treatment that has performed better in the trial up to that point. One probability model useful in generating an adaptive randomization scheme is an urn model. We will give a short overview of such adaptive models and compare four of them. We will be interested in how these four models minimize the number of treatment failures in a clinical trial with dichotomous response treatments. Comparison will be done via simulations for four treatments and exactly for three treatments for moderate sample sizes. We compare designs under the assumption that the results of treatments are known immediately, and we also allow some delay in response. Power is analyzed under various alternatives. Our results indicate that a birth and death urn with immigration is the best unless success probabilities are very small, in which case a randomized version of Polya's urn is preferred.