Validation in Indonesia of two published scores for mortality prediction after cardiac surgery

Introduction: No mortality risk prediction model has previously been validated for cardiac surgery in Indonesia. This study aimed at validating the EuroSCORE II and Age Creatinine Ejection Fraction (ACEF) score as predictors for in-hospital mortality after cardiac surgery a in tertiary center, and if necessary, to recalibrate the EuroSCORE II model to our population. Methods: This study was a single-center observational study from prospectively collected data on adult patients undergoing cardiac surgery from January 2006 to December 2011 (n = 1833). EuroSCORE II and ACEF scores were calculated for all patients to predict in-hospital mortality. Discrimination was assessed using the area under the curve (AUC) with a 95% confidence interval. Calibration was assessed with the Hosmer-Lemeshow test (HL test). Multivariable analysis was performed to recalibrate the EuroSCORE II; variables with P < 0.2 entered the final model. Results: The in-hospital mortality rate was 3.8%, which was underestimated by the EuroSCORE II (2.1%) and the ACEF score (2.4%). EuroSCORE II (AUC 0.774 (0.714-0.834)) showed good discrimination, whereas the ACEF score (AUC 0.638 [0.561-0.718]) showed poor discrimination. The differences in AUC were significant (P = 0.002). Both scores were poorly calibrated (EuroSCORE II: HL test P < 0.001, ACEF score: HL test P < 0.001) and underestimated mortality in all risk groups. After recalibration, EuroSCORE II showed good discrimination (AUC 0.776 [0.714- 0.840]) and calibration (HL test P = 0.79). Conclusions: EuroSCORE II and the ACEF score were unsuitable for risk prediction of in-hospital mortality after cardiac surgery in our center. Following recalibration, the calibration of the EuroSCORE II was greatly improved.