Bernardo M V, Harrington D P
Department of Biostatistics, Harvard School of Public Health, USA.
Stat Med. 2001 Feb 28;20(4):557-79. doi: 10.1002/sim.693.
In this paper we propose formulae for calculating the expected number of events or, alternatively, the required trial duration, for clinical trials involving two treatment groups in which patients may potentially experience multiple events and the data will be analysed using a multiplicative intensity (MI) model. We use a partial likelihood-based approach and examine in detail two MI models: one that includes a binary treatment variable as the only covariate and a three-state Markov process model in which a binary time-varying covariate is added to the previous model. For the simpler model, our formula coincides with those derived by Cook using full likelihood methods. We present applications of the derived formulae to chronic granulomatous disease and breast cancer data sets.
在本文中，我们提出了用于计算预期事件数的公式，或者，对于涉及两个治疗组的临床试验，计算所需的试验持续时间的公式。在这些试验中，患者可能会经历多个事件，并且将使用乘性强度（MI）模型对数据进行分析。我们采用基于部分似然的方法，并详细研究了两个MI模型：一个模型将二元治疗变量作为唯一协变量，另一个是三状态马尔可夫过程模型，其中在前一个模型中添加了一个二元时变协变量。对于较简单的模型，我们的公式与库克使用全似然方法得出的公式一致。我们展示了所推导公式在慢性肉芽肿病和乳腺癌数据集上的应用。
