Propensity Score Methods for Creating Covariate Balance in Observational Studies
Propensity Score Methods for Creating Covariate Balance in Observational Studies
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DOI：
10.1016/j.recesp.2011.06.008
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发表时间：
2011-10-01
影响因子：
5.9
通讯作者：
Zell, Elizabeth R.
中科院分区：
文献类型：
--
作者：
Pattanayak, Cassandra W.;Rubin, Donald B.;Zell, Elizabeth R.
实验中治疗分配的随机化产生具有近似平衡基线协变量的治疗组。然而，在观察性研究中，治疗分配不是随机的，积极治疗组和对照组的患者通常在与结果相关的关键协变量上存在差异。这些协变量不平衡可能导致治疗效果估计有偏倚。倾向评分是指具有特定基线特征的患者被分配到积极治疗组而不是对照组的概率。虽然观察性研究中的倾向得分是未知的，但通过对估计倾向得分的患者进行匹配或细分，我们可以设计与随机实验平行的观察性研究，观察到的协变量大致平衡。基于估计倾向得分的观察性研究设计可以产生近似无偏的治疗效果估计。关键的是，倾向评分设计应该在没有结果的情况下创建，反映随机实验中研究设计和结果分析的分离。本文描述了因果推理的潜在结果框架和设计倾向评分观察性研究的最佳实践。我们讨论了在两项研究中使用倾向评分来评估心脏手术期间抗纤溶药物的有效性和风险。全文可从以下网址获得：www.revespcardiol.org由爱思唯尔西班牙，S.L.代表西班牙心脏病学会出版。
Randomization of treatment assignment in experiments generates treatment groups with approximately balanced baseline covariates. However, in observational studies, where treatment assignment is not random, patients in the active treatment and control groups often differ on crucial covariates that are related to outcomes. These covariate imbalances can lead to biased treatment effect estimates. The propensity score is the probability that a patient with particular baseline characteristics is assigned to active treatment rather than control. Though propensity scores are unknown in observational studies, by matching or subclassifying patients on estimated propensity scores, we can design observational studies that parallel randomized experiments, with approximate balance on observed covariates. Observational study designs based on estimated propensity scores can generate approximately unbiased treatment effect estimates. Critically, propensity score designs should be created without access to outcomes, mirroring the separation of study design and outcome analysis in randomized experiments. This paper describes the potential outcomes framework for causal inference and best practices for designing observational studies with propensity scores. We discuss the use of propensity scores in two studies assessing the effectiveness and risks of antifibrinolytic drugs during cardiac surgery. Full English text available from: www.revespcardiol.org Published by Elsevier Espana, S.L. on behalf of the Sociedad Espanola de Cardiologia.