Renal Department, Southmead Hospital, North Bristol National Health Service Trust, Bristol, United Kingdom.
School of Health and Related Research, University of Sheffield, Sheffield, United Kingdom.
Transpl Int. 2022 Jun 27;35:10105. doi: 10.3389/ti.2022.10105. eCollection 2022.
Inferring causality from observational studies is difficult due to inherent differences in patient characteristics between treated and untreated groups. The randomised controlled trial is the gold standard study design as the random allocation of individuals to treatment and control arms should result in an equal distribution of known and unknown prognostic factors at baseline. However, it is not always ethically or practically possible to perform such a study in the field of transplantation. Propensity score and instrumental variable techniques have theoretical advantages over conventional multivariable regression methods and are increasingly being used within observational studies to reduce the risk of confounding bias. An understanding of these techniques is required to critically appraise the literature. We provide an overview of propensity score and instrumental variable techniques for transplant clinicians, describing their principles, assumptions, strengths, and weaknesses. We discuss the different patient populations included in analyses and how to interpret results. We illustrate these points using data from the Access to Transplant and Transplant Outcome Measures study examining the association between pre-transplant cardiac screening in kidney transplant recipients and post-transplant cardiac events.
由于治疗组和未治疗组患者特征存在固有差异，因此从观察性研究中推断因果关系较为困难。随机对照试验是金标准研究设计，因为个体随机分配到治疗组和对照组应该导致在基线时已知和未知预后因素的均衡分布。然而，在移植领域，并非总是在伦理上或实际上可行进行此类研究。倾向评分和工具变量技术在理论上优于传统的多变量回归方法，并越来越多地在观察性研究中用于降低混杂偏倚的风险。为了批判性地评估文献，需要了解这些技术。我们为移植临床医生提供了关于倾向评分和工具变量技术的概述，描述了它们的原理、假设、优点和缺点。我们讨论了分析中包含的不同患者人群以及如何解释结果。我们使用来自 Access to Transplant 和 Transplant Outcome Measures 研究的数据来说明这些要点，该研究检查了肾移植受者移植前心脏筛查与移植后心脏事件之间的关联。
