Elashoff J D, Koch G G, Chi G Y
Department of Biomathematics, UCLA School of Medicine 90024.
Stat Med. 1988 Aug;7(8):877-88. doi: 10.1002/sim.4780070806.
We describe a Markov chain model for the ulcer recurrence and healing process, review the available literature to obtain appropriate parameter estimates, and use this model to evaluate alternative clinical trial designs. We focus on designs aimed at supporting recurrence prevention claims for a duodenal ulcer maintenance treatment. Our results show that a trial with endoscopies scheduled only at four month intervals is inadequate to support recurrence prevention claims; discrimination between the null and alternative hypotheses is impossible because of the size and direction of expected biases in observed recurrences. Our results suggest that endoscopy intervals should be at most four weeks to establish a claim of ulcer prevention.
我们描述了一个用于溃疡复发和愈合过程的马尔可夫链模型，回顾现有文献以获得适当的参数估计，并使用该模型评估替代的临床试验设计。我们专注于旨在支持十二指肠溃疡维持治疗预防复发主张的设计。我们的结果表明，仅每四个月安排一次内窥镜检查的试验不足以支持预防复发的主张；由于观察到的复发中预期偏差的大小和方向，无法区分原假设和备择假设。我们的结果表明，内窥镜检查间隔应至多为四周，以确立溃疡预防的主张。
