European system for cardiac operative risk evaluation (EuroSCORE

Objective: To construct a scoring system for the prediction of early mortality in cardiac surgical patients in Europe on the basis of objective risk factors. Methods: The EuroSCORE database was divided into developmental and validation subsets. In the former, risk factors deemed to be objective, credible, obtainable and dif®cult to falsify were weighted on the basis of regression analysis. An additive score of predicted mortality was constructed. Its calibration and discrimination characteristics were assessed in the validation dataset. Thresholds were de®ned to distinguish low, moderate and high risk groups. Results: The developmental dataset had 13 302 patients, calibration by Hosmer Lemeshow Chi square was \u858 8:26 (P, 0:40) and discrimination by area under ROC curve was 0.79. The validation dataset had 1479 patients, calibration Chi square \u8510 7:5, P, 0:68 and the area under the ROC curve was 0.76. The scoring system identi®ed three groups of risk factors with their weights (additive % predicted mortality) in brackets. Patient-related factors were age over 60 (one per 5 year