Global Registry of Acute Coronary Events Score Underestimates Post-Acute Coronary Syndrome Mortality among Cancer Patients

Background Patients with prior cancer are at increased risk of acute coronary syndrome (ACS) with poorer post-ACS outcomes. We aimed to ascertain if the Global Registry of Acute Coronary Events (GRACE) score accurately predicts mortality risk among patients with ACS and prior cancer. Methods We linked nationwide ACS and cancer registries from 2007 to 2018 in Singapore. A total of 24,529 eligible patients had in-hospital and 1-year all-cause mortality risk calculated using the GRACE score (2471 prior cancer; 22,058 no cancer). Results Patients with prior cancer had two-fold higher all-cause mortality compared to patients without cancer (in-hospital: 22.8% versus 10.3%, p < 0.001; 1-year: 49.0% vs. 18.7%, p < 0.001). Cardiovascular mortality did not differ between groups (in-hospital: 5.2% vs. 4.8%, p = 0.346; 1-year: 6.9% vs. 6.1%, p = 0.12). The area under the receiver operating characteristic curve of the GRACE score for prediction of all-cause mortality was less for prior cancer (in-hospital: 0.64 vs. 0.80, p < 0.001; 1-year: 0.66 vs. 0.83, p < 0.001). Among patients with prior cancer and a high-risk GRACE score > 140, in-hospital revascularization was not associated with lower cardiovascular mortality than without in-hospital revascularization (6.7% vs. 7.6%, p = 0.50). Conclusions The GRACE score performs poorly in risk stratification of patients with prior cancer and ACS.