Abstract

In an observational study, to investigate the treatment effect, one common strategy is to match the control subjects to the treated subjects. The outcomes between the two groups are then compared after the TC (treatment-control) match. However, when the outcome is rare, detection of an outcome difference can be challenging. An alternative approach is to compare the treatment or exposure discrepancy after matching subjects with the outcome (cases) to subjects without the outcome (referents). Throughout the article, we follow the tradition to call this the matched “case-control” approach instead of the matched “case-referent” approach. We reserve “control” to mean not taking the treatment, and the abbreviation TC and CC (case-control) when possible confusion may arise. We derive conditions when the matched CC approach has more power for testing the treatment effect and examine its empirical performance in simulations and in our data example. We also show that the CC approach gives better match quality in our study of the effect of long vs. short stay in the hospital after joint surgery.

摘要

在一项观察性研究中，为了调查治疗效果，一种常见的策略是将对照受试者与治疗受试者相匹配。然后在 TC（治疗-对照）匹配后比较两组之间的结果。然而，当结果罕见时，检测结果差异可能具有挑战性。另一种方法是比较有结果的受试者（病例）与没有结果的受试者（参照物）后的治疗或暴露差异。在整篇文章中，我们遵循传统将其称为匹配的“病例对照”方法，而不是匹配的“病例参考”方法。我们保留“对照”表示不接受治疗，并在可能出现混淆时使用缩写 TC 和 CC（病例对照）。当匹配的 CC 方法具有更大的测试治疗效果的能力时，我们得出条件，并在模拟和我们的数据示例中检查其经验性能。我们还表明，CC 方法在我们对关节手术后住院时间与短期住院效果的研究中提供了更好的匹配质量。