Giammaria M, Maisano F, Bobbio M, Cuni D, Alfieri O, Pinna Pintor P
Dipartimento di Cardiochirurgia, Fondazione Arturo Pinna Pintor, Torino.
G Ital Cardiol. 1998 Nov;28(11):1261-72.
The need to assess the quality of heart surgery outcomes stimulated the development of pre-surgical risk stratification models in order to predict outcome on the basis of patient characteristics. The aim of the study was to compare the predictive accuracy of hospital mortality according to the following three models: Parsonnet (NBI Score), Higgins (CCF Score) and Roques (French Score), in a setting totally independent from the one in which the models were derived.
For each of the 516 patients undergoing heart surgery at our institution between January 1992 and December 1993, we calculated the pre-surgical risk according to the three models. Then we compared the predicted mortality against the observed mortality by means of the Shannon accuracy index, the ROC curve analysis and the overestimation histogram.
Overall observed mortality (1.5%) was similar to the predicted mortality by the NBI Score (1.5 +/- 2.1%, p = ns), the CCF Score (1.7 +/- 2.0%, p = ns) and the French Score (1.9 +/- 2.5%, p = ns). The predictive accuracy of global mortality is very high and equal with the three models, and it is very low in the 8 patients who died (NBI Score = 0.06 +/- 0.06; CCF Score = 0.125 +/- 0.067; French Score = 0.102 +/- 0.07, p = ns). The area under the ROC curve is identical in the 3 models.
The predicted mortality obtained by the three models is not significantly different from the observed mortality and therefore, the global accuracy is similar and very high, while it is very low for patients who will die. The models for pre-surgical risk stratification are useful for comparing the results among different institutions or different surgeons, or for monitoring the results over time in the same institution, but they cannot be used to accurately predict the individual risk of hospital mortality.
评估心脏手术结果质量的需求促使了术前风险分层模型的发展，以便根据患者特征预测结果。本研究的目的是在完全独立于模型推导环境的情况下，比较以下三种模型对医院死亡率的预测准确性：帕森内特（NBI评分）、希金斯（CCF评分）和罗克斯（法国评分）。
对于1992年1月至1993年12月在我们机构接受心脏手术的516例患者中的每一例，我们根据这三种模型计算术前风险。然后，我们通过香农准确性指数、ROC曲线分析和高估直方图将预测死亡率与观察到的死亡率进行比较。
总体观察到的死亡率（1.5%）与NBI评分预测的死亡率（1.5±2.1%，p=无显著性差异）、CCF评分（1.7±2.0%，p=无显著性差异）和法国评分（1.9±2.5%，p=无显著性差异）相似。三种模型的总体死亡率预测准确性非常高且相同，而在8例死亡患者中预测准确性非常低（NBI评分=0.06±0.06；CCF评分=0.125±0.067；法国评分=0.102±0.07，p=无显著性差异）。三种模型的ROC曲线下面积相同。
三种模型获得的预测死亡率与观察到的死亡率无显著差异，因此总体准确性相似且非常高，而对于将死亡的患者则非常低。术前风险分层模型有助于比较不同机构或不同外科医生之间的结果，或用于监测同一机构随时间的结果，但它们不能用于准确预测医院死亡率的个体风险。
