Department of Bioinformatics and Biostatistics, University of Louisville, Louisville, KY, USA.
Department of Anesthesiology & Perioperative Medicine, University of Louisville, Louisville, KY, USA.
Stat Methods Med Res. 2020 Dec;29(12):3623-3640. doi: 10.1177/0962280220934847. Epub 2020 Jul 8.
Propensity score methods are commonly used in statistical analyses of observational data to reduce the impact of confounding bias in estimations of average treatment effect. While the propensity score is defined as the conditional probability of a subject being in the treatment group given that subject's covariates, the most precise estimation of average treatment effect results from specifying the propensity score as a function of true confounders and predictors only. This property has been demonstrated via simulation in multiple prior research articles. However, we have seen no theoretical explanation as to why this should be so. This paper provides that theoretical proof. Furthermore, this paper presents a method for performing the necessary variable selection by means of elastic net regression, and then estimating the propensity scores so as to obtain optimal estimates of average treatment effect. The proposed method is compared against two other recently introduced methods, outcome-adaptive lasso and covariate balancing propensity score. Extensive simulation analyses are employed to determine the circumstances under which each method appears most effective. We applied the proposed methods to examine the effect of pre-cardiac surgery coagulation indicator on mortality based on a linked dataset from a retrospective review of 1390 patient medical records at Jewish Hospital (Louisville, KY) with the Society of Thoracic Surgeons database.
倾向评分方法常用于观察性数据分析中，以减少在估计平均治疗效果时混杂偏差的影响。虽然倾向评分被定义为给定个体协变量的情况下个体被分配到治疗组的条件概率，但从指定倾向评分仅作为真实混杂因素和预测因素的函数中得出平均治疗效果的最精确估计。这一特性已在多篇先前的研究文章中通过模拟得到证明。然而，我们没有看到任何理论解释为什么应该如此。本文提供了理论证明。此外，本文提出了一种通过弹性网络回归进行必要变量选择的方法，然后估计倾向评分，以获得平均治疗效果的最佳估计。所提出的方法与最近引入的两种方法进行了比较，即结果自适应套索和协变量平衡倾向评分。通过广泛的模拟分析，确定了每种方法在哪些情况下最有效。我们应用所提出的方法，根据来自犹太医院（肯塔基州路易斯维尔）的 1390 例患者病历的回顾性研究与胸外科医生协会数据库的链接数据集，研究了术前凝血指标对死亡率的影响。
