Tunes-da-Silva Gisela, Klein John P
Department of Statistics, University of São Paulo, São Paulo, São Paulo, Brazil.
Comput Stat Data Anal. 2011 Jan 1;55(1):226-235. doi: 10.1016/j.csda.2010.02.016.
We consider the problem of dichotomizing a continuous covariate when performing a regression analysis based on a generalized estimation approach. The problem involves estimation of the cutpoint for the covariate and testing the hypothesis that the binary covariate constructed from the continuous covariate has a significant impact on the outcome. Due to the multiple testing used to find the optimal cutpoint, we need to make an adjustment to the usual significance test to preserve the type-I error rates. We illustrate the techniques on one data set of patients given unrelated hematopoietic stem cell transplantation. Here the question is whether the CD34 cell dose given to patient affects the outcome of the transplant and what is the smallest cell dose which is needed for good outcomes.
在基于广义估计方法进行回归分析时，我们考虑对连续协变量进行二分的问题。该问题涉及协变量切点的估计，以及检验由连续协变量构建的二元协变量对结果有显著影响的假设。由于用于寻找最优切点的多重检验，我们需要对常规显著性检验进行调整，以保持I型错误率。我们在一组接受无关造血干细胞移植的患者数据集上展示这些技术。这里的问题是给予患者的CD34细胞剂量是否会影响移植结果，以及良好结果所需的最小细胞剂量是多少。
