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arXiv 1710.02011stat.ME
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中介-结果混杂条件下路径特异性效应的半参数估计

On semiparametric estimation of a path-specific effect in the presence of mediator-outcome confounding

Caleb H. Miles, Ilya Shpitser, Phyllis Kanki, Seema Meloni, Eric J. Tchetgen Tchetgen

摘要:

途径特异性效应是通过一个或多个因果途径,与中间变量的某个子集相关,从暴露到结果的广泛一类介导效应。大多数关于估计介导效应的文献都集中在参数模型上,对未测量的混杂因素进行了严格的假设。当这些假设被放松时,我们考虑特定路径效应的半参数推断。特别是,我们开发了一套半参数估计的效果沿着一条途径,通过一个调解人,但不是一些不确定性引起的混杂因素,该调解人。这些估计量具有不同的鲁棒性,因为每个估计量取决于观测数据可能性的不同部分。我们的估计之一可以被看作是结合其他的,因为它是局部半参数有效的和乘法鲁棒的。后一个属性是在模拟研究中说明。我们将我们的方法应用于HIV研究,在该研究中,我们估计比较两种药物治疗对患者的平均对数CD 4计数的影响,该患者的依从性水平介导,但不是由先前的毒性经验,这显然是受患者分配到哪种治疗的影响,并且可能混淆患者的依从性水平对他们的病毒学结果的影响。

英文摘要:

Path-specific effects are a broad class of mediated effects from an exposure to an outcome via one or more causal pathways with respect to some subset of intermediate variables. The majority of the literature concerning estimation of mediated effects has focused on parametric models with stringent assumptions regarding unmeasured confounding. We consider semiparametric inference of a path-specific effect when these assumptions are relaxed. In particular, we develop a suite of semiparametric estimators for the effect along a pathway through a mediator, but not some exposure-induced confounder of that mediator. These estimators have different robustness properties, as each depends on different parts of the observed data likelihood. One of our estimators may be viewed as combining the others, because it is locally semiparametric efficient and multiply robust. The latter property is illustrated in a simulation study. We apply our methodology to an HIV study, in which we estimate the effect comparing two drug treatments on a patient's average log CD4 count mediated by the patient's level of adherence, but not by previous experience of toxicity, which is clearly affected by which treatment the patient is assigned to, and may confound the effect of the patient's level of adherence on their virologic outcome.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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