From the aDepartment of Biostatistics, University of Copenhagen, Copenhagen, Denmark; and bDepartment of Cardiology, Copenhagen University Hospital, Gentofte, Denmark.
Epidemiology. 2014 Jan;25(1):110-3. doi: 10.1097/EDE.0000000000000001.
The case-time-control design is an extension of the case-crossover design capable of handling time trends in the exposure of the general population. Time-invariant confounders are controlled for by the design itself. The idea is to compare the exposure status of a person in one or several reference periods during which no event occurred with the exposure status of the same person in the index period where the event occurred. By comparing case-crossover results in cases to case-crossover results in controls, the exposure-outcome association can be estimated by conditional logistic regression. We review the mathematical assumptions underlying the case-time-control design and examine sensitivity to deviations from the assumed independence of within-individual exposure history. Results from simulating various scenarios suggest that the design is quite robust to deviations from this model assumption. In addition, we show that changes in exposure probability over time can be modeled in a flexible way using splines.
病例时间对照设计是病例交叉设计的一种扩展，能够处理一般人群中暴露的时间趋势。时间不变混杂因素由设计本身控制。其思想是将一个人在一个或多个参考期内没有发生事件时的暴露状态与该人在发生事件的索引期内的暴露状态进行比较。通过比较病例交叉病例的结果与对照的病例交叉结果，可以通过条件逻辑回归估计暴露-结局关联。我们回顾了病例时间对照设计的数学假设，并研究了对个体内暴露史独立性假设的偏离的敏感性。模拟各种情况的结果表明，该设计对偏离该模型假设具有很强的稳健性。此外，我们还表明，随着时间的推移，暴露概率的变化可以使用样条以灵活的方式进行建模。
