Validation of the EuroSCORE Probabilistic Model in Patients Undergoing Coronary Bypass Grafting

Introduction and objectives. EuroSCORE utilizes a probabilistic model for predicting the risk of in-hospital mortality in patients undergoing cardiac surgery. It is a useful instrument for evaluating quality of care. The model has two variants: the logistic EuroSCORE and the additive EuroSCORE. The aim of this study was to validate the EuroSCORE model in patients undergoing surgery at Hospital Clinic in Barcelona, Spain, and to compare the results obtained with the 2 variants. Methods. The study included all patients who received a coronary artery bypass graft (CABG) at Hospital Clinic in Barcelona in 2 consecutive years. The model’s validity was assessed on the basis of its calibration (using the HosmerLemeshow test) and its discrimination (using the receiver operating characteristic [ROC] curve). The 2 models were compared by carrying out a descriptive analysis of mortality for the whole group and for different risk groups, and by determining the models’ discriminative power. Results. A total of 498 patients underwent CABG surgery and were included in the study. The HosmerLemeshow test showed that the model’s calibration was satisfactory (P=.32) and the area under the ROC curve was 0.83. The observed in-hospital mortality rate was 5.8%. The predicted rate was 4.2% with the logistic EuroSCORE and 3.9% with the additive EuroSCORE. Large differences were observed in high-risk patients. In these patients, the mortality predicted by the logistic variant was closer to the actual mortality. Conclusions. EuroSCORE’s validity was found to be satisfactory and the model can be used to evaluate quality of care. In high-risk patients, mortality estimated using the logistic model was closer to the actual mortality.