The Global Registry of Acute Coronary Events (GRACE) score is recommended for stratifying chest pain. However, there are six formulas used to calculate the GRACE score for different outcomes of acute coronary syndrome (ACS), including death (Dth) or composite of death and myocardial infarction (MI), during in hospital (IH), in 6 months after discharge (OH6m) or from admission to 6 months later (IH6m). The more appropriate one for stratification of undifferentiated chest pain remains unclear. We aimed to provide firstly comprehensive evaluation and comparison of six GRACE models to predict 30-day major adverse cardiac events (MACE) in acute chest pain at the emergency department (ED).
Patients with acute chest pain were consecutively recruited from August 24, 2015 to September 30, 2017 in EDs of two public hospitals in China. The primary outcome was MACE within 30 days, including death, acute myocardial infarction (MI), emergency revascularization, cardiac arrest and cardiogenic shock. GRACE scores were calculated retrospectively using the prospectively obtained data. Correlation, calibration, discrimination and reclassification of six GRACE models were evaluated.
A total of 2886 patients were analyzed, with 590 (20.4%) patients getting outcomes. The GRACE (IH6mDthMI), GRACE (IHDthMI), GRACE (IHDth), GRACE (IH6mDth), GRACE (OH6mDth) and GRACE (OH6mDthMI) showed positive linear correlation with actual MACE rates (r≥0.568, p<0.001), first two of which exerted very strong relationships (r>0.9). All these models had good calibration (Hosmer-Lemeshow goodness-of-fit test, p≥0.073) except GRACE (IHDthMI) (p<0.001). The corresponding c-statistics were 0.82(0.81,0.83), 0.83(0.81,0.84), 0.75(0.73,0.76), 0.73(0.72,0.75), 0.72(0.70,0.73) and 0.70(0.68,0.71). Improvement in AUC, NRI and IDI (p<0.001) represented that GRACE (IH6mDthMI) and GRACE (IHDthMI) were superior to other four models in discrimination and reclassification.
The GRACE (IH6mDthMI) and GRACE (IHDthMI) outperformed other GRACE models in discriminating high or low-risk of 30-day MACE in patients with chest pain. The reasonable application of appropriate GRACE models should be recommended on stratification of undifferentiated chest pain presenting to the ED.