MODELING PROGRESSION OF CD4-LYMPHOCYTE COUNT AND ITS RELATIONSHIP TO SURVIVAL-TIME
MODELING PROGRESSION OF CD4-LYMPHOCYTE COUNT AND ITS RELATIONSHIP TO SURVIVAL-TIME
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作者：
DEGRUTTOLA, V;TU, XM
这篇文章的目的是模拟CD4淋巴细胞计数的进程，以及这种进程的不同特征与生存时间之间的关系。这一分析中的复杂因素是，只在某些固定的时间观察到CD4-淋巴细胞计数，并且具有很高的测量误差，并且观察载体的长度部分地取决于生存时间。如果死亡的概率取决于真实的、未观察到的CD4淋巴细胞计数，那么必须对生存过程进行建模。Wu和Carroll(1988，Biometrics 44,175-188)提出了一个两样本纵向数据的随机效应模型，其中个体效应只包括坡度和截距。我们提出了一种方法来拟合这类广泛的模型，其中重复的CD4-淋巴细胞计数和存活时间都是使用随机效应建模的。这些方法使我们能够估计描述CD4淋巴细胞计数进展的参数以及CD4轨迹的差异对生存的影响。我们将这些方法应用于艾滋病临床试验的结果。
The purpose of this article is to model the progression of CD4-lymphocyte count and the relationship between different features of this progression and survival time. The complicating factors in this analysis are that the CD4-lymphocyte count is observed only at certain fixed times and with a high degree of measurement error, and that the length of the vector of observations is determined, in part, by the length of survival. If probability of death depends on the true, unobserved CD4-lymphocyte count, then the survival process must be modelled. Wu and Carroll (1988, Biometrics 44, 175-188) proposed a random effects model for two-sample longitudinal data in the presence of informative censoring, in which the individual effects included only slopes and intercepts. We propose methods for fitting a broad class of models of this type, in which both the repeated CD4-lymphocyte counts and the survival time are modelled using random effects. These methods permit us to estimate parameters describing the progression of CD4-lymphocyte count as well as the effect of differences in the CD4 trajectory on survival. We apply these methods to results of AIDS clinical trials.