A time-dependent discrimination index for survival data
A time-dependent discrimination index for survival data
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DOI：
10.1002/sim.2427
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发表时间：
2005-12-30
影响因子：
2
通讯作者：
Biganzoli, E
中科院分区：
文献类型：
--
作者：
Antolini, L;Boracchi, P;Biganzoli, E
为了推导出适合结果预测的模型，一个关键的方面是预测准确性的适当度量的可用性，它必须可用于一般类型的模型。Harrell’s C判别指数是ROC曲线下面积的延伸，适用于经审查的生存数据，具有直接的可解释性。对于包括具有时间依赖效应的协变量和/或时间依赖的协变量的模型，C的原始定义将需要预测单个失效时间，这在大多数临床应用中通常没有得到解决。在这里，我们提出了一个时间依赖的区分指数C-td，其中整个预测生存函数被用作结果预测，并随着时间的推移总结具有不同结果的受试者之间的区分能力。Ctd是基于对一致性的一种新的定义：与任何活得更久的受试者相比，发生该事件的受试者在超过其生存时间后存活的预测概率应该更小。将发展该事件的受试者的预测生存函数与：(1)在其生存时间之前发展该事件的受试者的预测生存函数与(2)在其生存时间之后发展该事件或被审查的受试者的预测生存函数进行比较。被审查的受试者与在观察时间之前发展事件的受试者进行比较。在整个随访中存在生存曲线分离时，该指数降至之前的C。利用相关单样本u统计量的叠刀法，导出了C-td的置信区间。该指标用于评估模型的鉴别能力，包括具有时间依赖效应的协变量，涉及辅助他莫昔芬治疗乳腺癌患者的复发时间。该模型来自意大利国立肿瘤研究所（instituto Nazionale）和米兰肿瘤研究所（INT）的596名前瞻性患者。在威尼斯CRIBT （Centro Regionale Indicatori Biochimici di tumor）提供的175例患者的独立测试数据集上验证了模型的识别能力。版权所有2005约翰威利父子有限公司
To derive models suitable for outcome prediction, a crucial aspect is the availability of appropriate measures of predictive accuracy, which have to be usable for a general class of models. The Harrell's C discrimination index is an extension of the area under the ROC curve to the case of censored survival data, which owns a straightforward interpretability. For a model including covariates with time-dependent effects and/or time-dependent covariates, the original definition of C would require the prediction of individual failure times, which is not generally addressed in most clinical applications. Here we propose a time-dependent discrimination index C-td where the whole predicted survival function is utilized as outcome prediction, and the ability to discriminate among subjects having different outcome is summarized over time. Ctd is based on a novel definition of concordance: a subject who developed the event should have a less predicted probability of surviving beyond his/her survival time than any subject who survived longer. The predicted survival function of a subject who developed the event is compared to: (1) that of subjects who developed the event before his/her survival time, and (2) that of subjects who developed the event, or were censored, after his/her survival time. Subjects who were censored are involved in comparisons with subjects who developed the event before their observed times. The index reduces to the previous C in the presence of separation between survival curves on the whole follow-up. A confidence interval for C-td is derived using the jackknife method on correlated one-sample U-statistics.The proposed index is used to evaluate the discrimination ability of a model, including covariates having time-dependent effects, concerning time to relapse in breast cancer patients treated with adjuvant tamoxifen. The model was obtained from 596 patients entered prospectively at Istituto Nazionale per to Studio a la Cura dei Tumori di Milano (INT). The model discrimination ability was validated on an independent testing data set of 175 patients provided by Centro Regionale Indicatori Biochimici di Tumore (CRIBT) in Venice. Copyright 2005 John Wiley & Sons, Ltd.