Objective
To assess the accuracy of Global Registry of Acute Coronary Events (GRACE) scores in predicting mortality at 6 months for people with COPD and to investigate how it might be improved.
Methods
Data were obtained on 481,849 patients with acute coronary syndrome (ACS) admitted to UK hospitals between January 2003-June 2013 from the myocardial ischaemia national audit project (MINAP) database. We compared risk of death between chronic obstructive pulmonary disease (COPD) and non-COPD patients at 6 months, adjusting for predicted risk of death. We then assessed whether several modifications improved the accuracy of the GRACE score for people with COPD.
Results
The risk of death after adjusting for GRACE score predicted risk of death was higher for COPD patients than for other patients (RR 1.29, 95% CI 1.28-1.33). Adding smoking into the GRACE score model did not improve accuracy for COPD patients. Either adding COPD into the model (RR 1.00, 0.94-1.02) or multiplying the GRACE score by 1.3 resulted in better performance (RR 0.99, 0.96-1.01).
Conclusion
GRACE scores underestimate risk of death for people with COPD. A more accurate prediction of risk of death can be obtained by adding COPD into the GRACE score equation, or by multiplying the GRACE score predicted risk of death by 1.3 for people with COPD. This means that one third of COPD patients currently classified as low risk should be classified as moderate risk, and could be considered for more aggressive early treatment after non-ST-elevation myocardial infarction or unstable angina.