CONSTRUCTION, VALIDATION AND UPDATING OF A PROGNOSTIC MODEL FOR KIDNEY GRAFT-SURVIVAL
CONSTRUCTION, VALIDATION AND UPDATING OF A PROGNOSTIC MODEL FOR KIDNEY GRAFT-SURVIVAL
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DOI：
10.1002/sim.4780141806
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发表时间：
1995-09-30
影响因子：
2
通讯作者：
THOROGOOD, J
中科院分区：
文献类型：
--
作者：
VANHOUWELINGEN, HC;THOROGOOD, J
利用欧洲移植数据库的数据，构建、验证和更新肾移植生存预后模型。首先，建立了1984 - 1987年移植数据的模型。该模型后来针对1988-1990年的数据进行了更新。第一个数据集被随机分成训练集（三分之二的数据）和验证集（三分之一）。为了防止过拟合，我们采用了移植中心效应的经验贝叶斯估计。之后，验证集用于通过收缩进行微调。为了与1988-1990年的数据进行更新，采用了对时间轴进行适当变换后的参数化模型；存活率似乎略有提高。这就需要对指数模型中的参数进行修正。通过对威布尔模型的扩展，验证了模型的正确性。缺乏拟合在统计上是显著的，但实际上可以忽略不计。建议减少对变量和截止点的选择，更多地强调通过独立数据集中的低维参数模型对预测模型进行微调。
The construction, validation and updating of a prognostic model for kidney graft survival is reported using data from the Eurotransplant database. First, a model is constructed for data from transplantations in the period 1984 to 1987. The model is later updated for the 1988-1990 data. The first data set was randomly split into a training set (two-thirds of the data) and a validation set (one-third). To prevent overfitting empirical Bayes estimation of the transplantation centre effect was employed. After that, the validation set was used for fine-tuning by shrinkage. For updating with the 1988-1990 data parametric models were used after suitable transformation of the time axis; it appeared that survival had slightly improved. This necessitated a correction of the parameters in the exponential model. Correctness of the model was checked by extension to a Weibull model. The lack of fit was statistically significant, but practically ignorable. Recommendations are made to place less emphasis on the selection of variables and cut-off points, and more emphasis on the fine-tuning of the prognostic model by means of low-dimensional parametric models in independent data sets.