Holder D A, Johnson A L, Stolberg H O, Campbell M, Gunstensen J, Joyal M, Roberts R, Biagioni E M, Vaughan W, Romeo M
Can J Cardiol. 1985 Jan;1(1):24-9.
Important clinical decisions are made on the basis of the interpretation of the degree of stenosis in the coronary cineangiogram. Thus, minimization of observer variation (both intra and inter) is crucial. The purpose of this investigation was to determine if measurement of stenotic lesions by caliper (CM) as compared with the usual eyeball method (EM) would reduce observer variation. Five observers, using the AHA scoring system, estimated maximal luminal narrowing in 14 segments on 10 films providing 2 reports on each film by EM and 2 by CM, thus making observations on 2800 segments. This allowed analysis of intraobserver variation for each reporter for method EM and CM, and for interobserver variation by each method. Since chance agreement is an important component in an observational study, a correction for this was made using the Kappa statistic. The results revealed that the mean Kappa by EM was 0.71 compared to 0.63 by CM (1 being perfect agreement and 0 no agreement). Agreement was much greater in proximal rather than distal segments. Interobserver agreement was consistently higher by EM K = 0.62 than CM K = 0.53 (p = 0.0007). A delineation of the types of disagreement and their clinical significance are important considerations in the evaluation of observer variation. It is concluded that the use of a caliper does not enhance either intra or interobserver agreement.
重要的临床决策是基于冠状动脉造影中狭窄程度的解读做出的。因此，将观察者间（包括观察者内和观察者间）的差异最小化至关重要。本研究的目的是确定与常用的目测法（EM）相比，使用卡尺测量狭窄病变（CM）是否会减少观察者间的差异。五名观察者使用美国心脏协会（AHA）评分系统，在10张胶片上对14个节段的最大管腔狭窄进行估计，每种方法在每张胶片上给出2份报告，因此共对2800个节段进行了观察。这使得可以分析每种方法下每个报告者的观察者内差异以及每种方法的观察者间差异。由于偶然一致性是观察性研究的一个重要组成部分，因此使用卡方统计量对此进行了校正。结果显示，目测法的平均卡方值为0.71，而卡尺测量法为0.63（1表示完全一致，0表示完全不一致）。近端节段的一致性远高于远端节段。观察者间的一致性在目测法（K = 0.62）下始终高于卡尺测量法（K = 0.53）（p = 0.0007）。在评估观察者间差异时，明确分歧类型及其临床意义是重要的考虑因素。得出的结论是，使用卡尺并不能提高观察者内或观察者间的一致性。
