Joint modeling of longitudinal ordinal data and competing risks survival times and analysis of the NINDS rt-PA stroke trial
Joint modeling of longitudinal ordinal data and competing risks survival times and analysis of the NINDS rt-PA stroke trial
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DOI：
10.1002/sim.3798
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发表时间：
2010-02-28
影响因子：
2
通讯作者：
Saver, Jeffrey
中科院分区：
文献类型：
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作者：
Li, Ning;Elashoff, Robert M.;Saver, Jeffrey
现有的纵向数据和生存数据的联合模型不适用于由多种原因引起的可能存在不可忽略的缺失值的纵向有序结果。我们提出了纵向有序测量和竞争风险失效时间数据的联合模型，其中纵向有序结果的部分比例优势模型通过潜在的随机变量与事件时间相联系。在生存终点，我们的模型采用竞争风险框架同时对多种失败类型进行建模。部分比例赔率模型是流行的序贯结果比例赔率模型的扩展，具有更大的灵活性，同时也提供了检验比例赔率假设的工具。我们使用似然方法并推导出EM算法来获得参数的最大似然估计。我们进一步证明，生存终点处的所有参数都可以从数据中识别出来。我们的联合模型使人们能够同时对纵向顺序结果和故障次数做出推断。此外，针对故障次数可能导致的不可忽略的丢失数据，调整纵向端点处的推断。我们将该方法应用于NINDS RT-PA卒中试验。我们的研究只考虑了修改后的Rankin量表。试验中的其他顺序结果，如Barthel和Glasgow量表，也可以用同样的方法处理。版权所有(C)2009 John Wiley&Sons，Ltd.
Existing joint models for longitudinal and survival data are not applicable for longitudinal ordinal outcomes with possible non-ignorable missing values caused by multiple reasons. We propose a joint model for longitudinal ordinal measurements and competing risks failure time data, in which a partial proportional odds model for the longitudinal ordinal outcome is linked to the event times by latent random variables. At the survival endpoint, our model adopts the competing risks framework to model multiple failure types at the same time. The partial proportional odds model, as an extension of the popular proportional odds model for ordinal outcomes, is more flexible and at the same time provides a tool to test the proportional odds assumption. We use a likelihood approach and derive an EM algorithm to obtain the maximum likelihood estimates of the parameters. We further show that all the parameters at the survival endpoint are identifiable from the data. Our joint model enables one to make inference for both the longitudinal ordinal outcome and the failure times simultaneously. in addition, the inference at the longitudinal endpoint is adjusted for possible non-ignorable missing data caused by the failure times. We apply the method to the NINDS rt-PA stroke trial. Our study considers the modified Rankin Scale only. Other ordinal outcomes in the trial, such as the Barthel and Glasgow scales, can be treated in the same way. Copyright (C) 2009 John Wiley & Sons, Ltd.