Self-Controlled Case Series Analysis With Event-Dependent Observation Periods
Self-Controlled Case Series Analysis With Event-Dependent Observation Periods
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DOI：
10.1198/jasa.2011.ap10108
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发表时间：
2011-06-01
影响因子：
3.7
通讯作者：
Smeeth, Liam
中科院分区：
文献类型：
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作者：
Farrington, C. Paddy;Anaya-Izquierdo, Karim;Smeeth, Liam
自我对照病例系列方法可用于研究随时间变化的暴露与健康事件之间的关联。它仅基于病例，并控制固定混杂因素。在预定义的观察期内收集每个病例的暴露和事件历史。该方法要求观测周期与事件发生时间无关。当事件增加死亡率时，违反了这一要求，因为观察期的删失取决于事件。在这篇文章中，罕见的非经常性事件的情况下，系列方法进行了扩展，以消除这种独立性的假设，从而引入了一个额外的条款的可能性，取决于审查过程。为了保持在仅对病例进行采样的病例系列框架内，对模型进行了重新参数化，以便从事件到观察结束的间隔分布中可以估计该附加项。可以无偏地估计主要兴趣的暴露效应。年龄效应，然而，采取了新的解释，纳入审查的效果。该模型可以在标准对数线性建模软件中拟合;这产生保守的标准误差。我们描述了一个详细的应用研究抗精神病药物和中风。当忽略事件相关的观测期时，从标准病例系列模型得到的估计值会有偏差。当允许使用抗精神病药物时，抗精神病药物的使用与痴呆患者的卒中仍有很强的正相关性，但与非痴呆患者无关。两个详细的模拟研究作为补充材料。
The self-controlled case series method may be used to study the association between a time-varying exposure and a health event. It is based only on cases, and it controls for fixed confounders. Exposure and event histories are collected for each case over a predefined observation period. The method requires that observation periods should be independent of event times. This requirement is violated when events increase the mortality rate, since censoring of the observation periods is then event dependent. In this article, the case series method for rare nonrecurrent events is extended to remove this independence assumption, thus introducing an additional term in the likelihood that depends on the censoring process. In order to remain within the case series framework in which only cases are sampled, the model is reparameterized so that this additional term becomes estimable from the distribution of intervals from event to end of observation. The exposure effect of primary interest may be estimated unbiasedly. The age effect, however, takes on a new interpretation, incorporating the effect of censoring. The model may be fitted in standard loglinear modeling software; this yields conservative standard errors. We describe a detailed application to the study of antipsychotics and stroke. The estimates obtained from the standard case series model are shown to be biased when event-dependent observation periods are ignored. When they are allowed for, antipsychotic use remains strongly positively associated with stroke in patients with dementia, but not in patients without dementia. Two detailed simulation studies are included as Supplemental Material.