Graf E, Schmoor C, Sauerbrei W, Schumacher M
Institute of Medical Biometry and Medical Informatics, University of Freiburg, Stefan-Meier-Strasse 26, D-79104 Freiburg, Germany.
Stat Med. 1999;18(17-18):2529-45. doi: 10.1002/(sici)1097-0258(19990915/30)18:17/18<2529::aid-sim274>3.0.co;2-5.
Prognostic classification schemes have often been used in medical applications, but rarely subjected to a rigorous examination of their adequacy. For survival data, the statistical methodology to assess such schemes consists mainly of a range of ad hoc approaches, and there is an alarming lack of commonly accepted standards in this field. We review these methods and develop measures of inaccuracy which may be calculated in a validation study in order to assess the usefulness of estimated patient-specific survival probabilities associated with a prognostic classification scheme. These measures are meaningful even when the estimated probabilities are misspecified, and asymptotically they are not affected by random censorship. In addition, they can be used to derive R(2)-type measures of explained residual variation. A breast cancer study will serve for illustration throughout the paper.
预后分类方案在医学应用中经常被使用，但很少对其充分性进行严格检验。对于生存数据，评估此类方案的统计方法主要由一系列特设方法组成，而且该领域令人担忧地缺乏普遍接受的标准。我们回顾这些方法并开发不准确度的度量，这些度量可在验证研究中计算出来，以便评估与预后分类方案相关的估计的患者特异性生存概率的有用性。即使估计概率被错误设定，这些度量也是有意义的，并且在渐近情况下它们不受随机删失的影响。此外，它们可用于推导解释残差变异的R(2)型度量。贯穿本文将以一项乳腺癌研究为例进行说明。
