Choosing sample size for a clinical trial using decision analysis
Choosing sample size for a clinical trial using decision analysis
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DOI：
10.1093/biomet/90.4.923
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发表时间：
2003-12-01
期刊：
影响因子：
2.7
通讯作者：
Berry, DA
中科院分区：
文献类型：
--
作者：
Cheng, Y;Su, FS;Berry, DA
考虑分阶段设计一项临床试验，采用两种治疗方法和 N 个可互换的接受治疗的患者。反应是二分的。问题是确定每个阶段的规模以及每个阶段应分配多少患者进行每种治疗。使用贝叶斯定理在每个阶段期间和之后更新信息。在规划阶段 j 中，阶段 I 至 j - I 中的选择的响应可用，但阶段 j 中的临时响应不可用。我们的分析结果考虑了两种情况的两个阶段，即当一个治疗组已知时和当两个治疗组未知时。明确找到一般 N 的优化设计中第一阶段长度的主导项。在这两种情况下，第一阶段长度的数量级都是 N 的平方根。将渐近最优分配的有限 N 性能与真正最优分配的性能进行比较。我们的数值研究还表明，对于一个已知臂的三个阶段的试验，最佳第一阶段样本量与 N 的立方根渐近成正比。
Consider designing a clinical trial in stages, with two treatments and N exchangeable patients to be treated. Responses are dichotomous. The problem is to decide how large each stage should be and how many patients should be assigned to each treatment during each stage. Information is updated during and after each stage using Bayes' theorem. In planning stage j, responses from selections in stages I to j - I are available, but interim responses in stage j are not available. Our analytical results consider two stages for two scenarios, when one treatment arm is known and when both treatment arms are unknown. The dominant term for the length of the first stage in an optimal design for general N is found explicitly. In both scenarios the order of magnitude of the length of the first stage is the square root of N. The finite-N performance of asymptotically optimal allocation is compared with that of the true optimal allocation. Our numerical study also shows that, for a trial of three stages with one known arm, the optimal first-stage sample size is asymptotically proportional to the cube root of N.