Raghunathan Karthik, Layton J Bradley, Ohnuma Tetsu, Shaw Andrew D
Department of Anesthesiology, Duke University Medical Center, Durham VA Medical Center, Durham, NC; Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC; and the Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN.
Department of Anesthesiology, Duke University Medical Center, Durham VA Medical Center, Durham, NC; Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC; and the Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN.
Adv Chronic Kidney Dis. 2016 Nov;23(6):367-372. doi: 10.1053/j.ackd.2016.11.010.
In most observational studies, treatments or other "exposures" (in an epidemiologic sense) do not occur at random. Instead, treatments or other such interventions depend on several patient-related and patient-independent characteristics. Such factors, associated with the receipt vs nonreceipt of treatment, may also be-independently-associated with outcomes. Thus, confounding exists making it difficult to ascertain the true association between treatments and outcomes. Propensity scores (PS) represent an intuitive set of approaches to reduce the influence of such "confounding" factors. PS is a computed probability of treatment, a value that is estimated for each patient in an observational study and then applied (in a variety of ways such as matching, stratification, weighting, etc.) to reduce distortion in the true nature of the association between treatment (or any similar exposure) and outcomes. Despite several advantages, PS-based methods cannot account for unmeasured confounding, ie, for factors that are not being included in the computation of PS.
在大多数观察性研究中，治疗或其他“暴露因素”（从流行病学意义上讲）并非随机出现。相反，治疗或其他此类干预措施取决于若干与患者相关及与患者无关的特征。这些与接受治疗与否相关的因素，也可能与结局独立相关。因此，存在混杂因素，使得难以确定治疗与结局之间的真正关联。倾向评分（PS）代表了一组直观的方法，用于减少此类“混杂”因素的影响。PS是治疗的计算概率，在观察性研究中为每个患者估计一个值，然后以各种方式（如匹配、分层、加权等）应用该值，以减少治疗（或任何类似暴露因素）与结局之间关联的真实性质的扭曲。尽管有几个优点，但基于PS的方法无法解释未测量的混杂因素，即未纳入PS计算的因素。
