Vergouwe Yvonne, Steyerberg Ewout W, Eijkemans Marinus J C, Habbema J Dik F
Center for Clinical Decision Sciences, Department of Public Health, Erasmus University Rotterdam, The Netherlands.
Semin Urol Oncol. 2002 May;20(2):96-107. doi: 10.1053/suro.2002.32521.
Prognostic models combine patient characteristics to predict medical outcomes. Unfortunately, such models do not always perform as well for other patients as those from whose data the models were derived. Therefore, validity of prognostic models needs to be assessed in new patients. Predicted probabilities can be calculated with the model and compared with the actually observed outcomes. We may distinguish several aspects of validity: (1) agreement between predicted probabilities and observed probabilities (calibration), (2) ability of the model to distinguish subjects with different outcomes (discrimination), and (3) ability of the model to improve the decision-making process (clinical usefulness). We discuss those aspects and show some measures by using models for testicular and prostate cancer. We conclude that good calibration and discriminative ability are not sufficient for a model to be clinically useful. Application of a prognostic model is sensible, if the model is able to provide useful additional information for clinical decision making.
预后模型结合患者特征来预测医疗结果。不幸的是，此类模型对其他患者的表现并不总是与构建模型所依据的数据来源患者相同。因此，需要在新患者中评估预后模型的有效性。可以使用该模型计算预测概率，并与实际观察到的结果进行比较。我们可以区分有效性的几个方面：（1）预测概率与观察概率之间的一致性（校准），（2）模型区分不同结果受试者的能力（区分度），以及（3）模型改善决策过程的能力（临床实用性）。我们讨论这些方面，并通过使用睾丸癌和前列腺癌模型展示一些测量方法。我们得出结论，良好的校准和区分能力不足以使模型具有临床实用性。如果模型能够为临床决策提供有用的附加信息，那么应用预后模型是明智的。
