Asakura Koko, Hamasaki Toshimitsu, Sugimoto Tomoyuki, Hayashi Kenichi, Evans Scott R, Sozu Takashi
Department of Biomedical Statistics, Osaka University Graduate School of Medicine, Osaka, Japan; Office of Biostatistics and Data Management, Research and Development Initiative Center, National Cerebral and Cardiovascular Center, Osaka, Japan.
Stat Med. 2014 Jul 30;33(17):2897-913. doi: 10.1002/sim.6154. Epub 2014 Mar 27.
We discuss sample size determination in group-sequential designs with two endpoints as co-primary. We derive the power and sample size within two decision-making frameworks. One is to claim the test intervention's benefit relative to control when superiority is achieved for the two endpoints at the same interim timepoint of the trial. The other is when superiority is achieved for the two endpoints at any interim timepoint, not necessarily simultaneously. We evaluate the behaviors of sample size and power with varying design elements and provide a real example to illustrate the proposed sample size methods. In addition, we discuss sample size recalculation based on observed data and evaluate the impact on the power and Type I error rate.
我们讨论在具有两个共同主要终点的序贯分组设计中样本量的确定。我们在两个决策框架内推导检验效能和样本量。一种是在试验的同一中期时间点两个终点均达到优效性时，宣称试验干预相对于对照的益处。另一种是在任何中期时间点两个终点均达到优效性时，不一定是同时达到。我们评估不同设计要素下样本量和检验效能的表现，并提供一个实际例子来说明所提出的样本量方法。此外，我们讨论基于观察数据的样本量重新计算，并评估其对检验效能和I型错误率的影响。
