Validation of the GRace Score (Global Registry of acute coronary events) as Predictor of in-hospital Mortality in acute coronary Syndromes in Buenos aires

pp 292-299

Abstract

Background: The GRACE score (GS) estimates the risk of in-hospital mortality (IHM) in patients with acute coronary syndromes (ACS). An external validation of the score is necessary due to the variability of patient characteristics, healthcare systems, socio economic environment and changes in treatment. The recently published TRIPOD guideline standardizes the methodology used in these validation studies.

objective: The objective of this study was to assess whether the GS adequately predicts IHM in patients with ACS treated at Hospital Dr. Juan A. Fernández [validation group (VG)].

Methods: A retrospective VG study was conducted between 2001 and 2016. Discrimination was evaluated using the area under the ROC curve (AUC) and calibration using the Hosmer Lemeshow goodness of fit test, calibration-in-the-large, calibration slope, validation plot and calibration belt. A subgroup analysis was performed by type of ACS: ST-segment elevation or non-ST-segment elevation ACS (STE-ACS or NSTE-ACS, respectively).

Results: A total of 2,104 patients were analyzed. ST-segment elevation myocardial infarction (40.4%) and IHM (5.56%) were more prevalent in the VG than in the population from which the GS was derived (32% and 4.6%, respectively). Model calibration was poor, due to risk underestimation in the probabilities ranging between 3% and 13%. The calibration slope was adequate, indicating that
the overall predictor effect on IHM was similar to the GS model. The AUC was 0.86. The model underestimated risk for probabilities ranging between 5% and 23% in patients with STE-ACS, with adequate discrimination. Calibration and discrimination had adequate performance in patients with NSTE-ACS.

conclusions: Despite the lack of statistical validity in the overall population, the GS model variables were predictors of IHM in the VG. Therefore, the GS is clinically relevant, but should be recalibrated in our population.