Background: The aim was to assess the utility of cumulative sum techniques for continuous monitoring of coronary care outcomes, applied to patients with acute coronary syndrome stratified by the Global Registry for Acute Coronary Events (GRACE) risk score.
Methods: A prospective longitudinal study to assess GRACE score for real-time monitoring of coronary care mortality in a community hospital was conducted between January 2012 and December 2017. An expected-to-observed probability of death chart for individual risk and a variable life-adjusted display were used to monitor the results.
Results: A total of 1,255 patients undergoing acute coronary syndrome were included in the analysis. GRACE-based variable life-adjusted plots monitoring in-hospital mortality showed that observed death rates remained in general within the expected 95% confidence limit over time, and these behaviors were similar for ST-segment elevation and non-ST-segment elevation myocardial infarction. In-hospital all-cause mortality was 2.6% for the overall population, and 56% of these cases corresponded to unexpected deaths; conversely, unexpected survival occurred in 5.2% of survivors.
Conclusions: Continuous monitoring of coronary care mortality based on cumulative sum charts and the GRACE score demonstrated the occurrence of series of favorable and unfavorable outcomes on a real-time basis. Additionally, plotting the expected-to-observed probability of death for individual cases was useful to individualize unexpected deaths in low-risk patients. Although overall coronary care performance was adequate according to the GRACE score, we found that there is still some room for improvement, since over half of the deaths occurring in low-risk patients were potentially preventable.