Application of the EuroSCORE in coronary artery bypass surgery in public hospitals in Rio de Janeiro, Brazil

Background: Risk stratification models are used to assess the risk of death in surgery. Objective: To conduct a critical analysis of the EuroSCORE logistic model (ES) application in 2,692 patients undergoing Coronary Artery Bypass Grafting (CABG) in four public hospitals in the Rio de Janeiro Municipality, from 1999 through to December 2003. Methods: Random samples of 150 medical records for surviving and deceased patients were selected at four public hospitals in the City of Rio de Janeiro. The ES was applied, using the logistical model. The observed lethality rate and that forecast by the model were compared. The measurement of the discriminatory power was estimated by the area under the ROC curve. Results: 546 of the 600 selected medical records were located. A significant difference was noted between the prevalence rates for the risk factors in the Brazilian and European populations. The forecast lethality rate was 3.62% (CI-95%: 3.47-3.78) while the estimated observed rate was 12.22% (CI-95%- 10.99-13.46). In all risk ranges, the predicted lethality rate is under-estimated, with notable differences between the predicted and observed rates. The area under the ROC curve was estimated at 0.62. Conclusion: The differences in the prevalence rates for the risk factors constituting the ES, associated with its low power of discrimination, hamper any recommendation of the use of this model in Brazil, without the necessary adjustments.