Pitkänen O, Niskanen M, Rehnberg S, Hippeläinen M, Hynynen M
Department of Anaesthesiology and Intensive Care, Kuopio University Hospital, FIN-70210, Kuopio, Finland.
Eur J Cardiothorac Surg. 2000 Dec;18(6):703-10. doi: 10.1016/s1010-7940(00)00579-0.
To construct models for predicting mortality, morbidity and length of intensive care unit (ICU) stay after cardiac surgery and to compare the performance of these models with that of the EuroSCORE in two independent validation databases.
Clinical data on 4592 cardiac surgery patients operated between 1992 and 1996 were retrospectively collected. In order to derive predictive models and to validate them, the patient population was randomly divided into a derivation database (n=3061) and a validation database (n=1531). Variables that were significant in univariate analyses were entered into a backward stepwise logistic regression model. The outcome was defined as mortality within 30 days after surgery, predefined morbidity, and the length of ICU stay lasting >2 days. In addition to the retrospective database, the models were validated also in a prospectively collected database of cardiac surgical patients operated in 1998-1999 (n=821). The EuroSCORE was tested in two validation databases, i.e. the retrospective and prospective one. Hosmer-Lemeshow goodness-of-fit was used to study the calibration of the predictive models. Area under the receiver operating characteristic (ROC) curve was used to study the discrimination ability of the models.
The overall mortality in the retrospective and the prospective data was 2 and 1%, and morbidity 22 and 18%, respectively. The created predictive models fitted well in the validation databases. Our models and the EuroSCORE were equally good in discriminating patients. Thus, in the prospective validation database, the mean areas under the ROC curve for our models and for the EuroSCORE were similar, i.e. 0.84 and 0.77 for mortality, 0.74 and 0.74 for morbidity, and 0.81 and 0.79 for the length of intensive care unit stay lasting for 2 days or more, respectively.
Our models and the EuroSCORE were equally good in discriminating the patients in respect to outcome. However, our model provided also well calibrated estimation of the probability of prolonged ICU stay for each patient. As was originally suggested, the EuroSCORE may be an appropriate tool in categorizing cardiac surgical patients into various subgroups in interinstitutional comparisons. Our models may have additive value especially in resource allocation and quality assurance purposes for local use.
构建预测心脏手术后死亡率、发病率及重症监护病房（ICU）住院时长的模型，并在两个独立验证数据库中将这些模型的性能与欧洲心脏手术风险评估系统（EuroSCORE）的性能进行比较。
回顾性收集1992年至1996年期间接受心脏手术的4592例患者的临床数据。为了推导并验证预测模型，将患者群体随机分为一个推导数据库（n = 3061）和一个验证数据库（n = 1531）。将单因素分析中有显著意义的变量纳入向后逐步逻辑回归模型。结局定义为术后30天内的死亡率、预先定义的发病率以及持续超过2天的ICU住院时长。除了回顾性数据库外，这些模型还在1998 - 1999年接受心脏手术患者的前瞻性收集数据库（n = 821）中进行了验证。欧洲心脏手术风险评估系统在两个验证数据库中进行了测试，即回顾性数据库和前瞻性数据库。采用Hosmer-Lemeshow拟合优度检验来研究预测模型的校准情况。采用受试者工作特征（ROC）曲线下面积来研究模型的辨别能力。
回顾性数据和前瞻性数据中的总体死亡率分别为2%和1%，发病率分别为22%和18%。所创建的预测模型在验证数据库中拟合良好。我们的模型和欧洲心脏手术风险评估系统在辨别患者方面同样出色。因此，在前瞻性验证数据库中，我们的模型和欧洲心脏手术风险评估系统的ROC曲线下平均面积相似，即死亡率分别为0.84和0.77，发病率分别为0.74和0.74，持续2天或更长时间的ICU住院时长分别为0.81和0.79。
我们的模型和欧洲心脏手术风险评估系统在根据结局辨别患者方面同样出色。然而，我们的模型还能对每位患者延长ICU住院的概率提供校准良好的估计。正如最初所建议的，欧洲心脏手术风险评估系统可能是在机构间比较中将心脏手术患者分类到不同亚组的合适工具。我们的模型可能具有附加价值，特别是在用于资源分配和本地质量保证目的方面。
