Flexible modelling of vaccine effect in self-controlled case series models.
Flexible modelling of vaccine effect in self-controlled case series models.
复制标题
自我对照病例系列模型中疫苗效果的灵活建模。
DOI：
10.1002/bimj.201400257
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
Ghebremichael-Weldeselassie Y
中科院分区：
文献类型：
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作者：
Ghebremichael-Weldeselassie Y
通常用于研究疫苗安全性的自身对照病例系列（SCCS）方法仅需要病例信息，并自动控制所有与年龄无关的倍增混杂因素，同时允许年龄依赖性基线发生率。目前，SCCS方法使用具有预定切割点的阶跃函数表示随时间变化的暴露。当与暴露相关的相对风险函数的形状事先未知时，特别是当暴露效应可能是长期的时，不那么规范的方法可能是有益的。因此，我们建议使用灵活的平滑函数模型曝光效果。具体来说，我们使用了三次M样条的线性组合，除了给出合理的形状外，还避免了SCCS模型的对数似然函数中的积分。这些方法虽然是专门为疫苗开发的，但适用范围更广。仿真结果表明，新方法的性能普遍优于阶跃函数法。我们将新方法应用于两个数据集，一个是热性惊厥和暴露于MMR疫苗，另一个是骨折和噻唑烷二酮使用。
The self‐controlled case series (SCCS) method, commonly used to investigate the safety of vaccines, requires information on cases only and automatically controls all age‐independent multiplicative confounders, while allowing for an age‐dependent baseline incidence. Currently, the SCCS method represents the time‐varying exposures using step functions with pre‐determined cut points. A less prescriptive approach may be beneficial when the shape of the relative risk function associated with exposure is not known a priori, especially when exposure effects can be long‐lasting. We therefore propose to model exposure effects using flexible smooth functions. Specifically, we used a linear combination of cubic M‐splines which, in addition to giving plausible shapes, avoids the integral in the log‐likelihood function of the SCCS model. The methods, though developed specifically for vaccines, are applicable more widely. Simulations showed that the new approach generally performs better than the step function method. We applied the new method to two data sets, on febrile convulsion and exposure to MMR vaccine, and on fractures and thiazolidinedione use.