Risk-standardized mortality metric to monitor hospital performance for chest pain presentations

AIMS: Risk-standardized mortality rates (RSMR) have been used to monitor hospital performance in procedural and disease-based registries, but limitations include the potential to promote risk-averse clinician decisions and a lack of assessment of the whole patient journey. We aimed to determine whether it is feasible to use RSMR at the symptom-level to monitor hospital performance using routinely collected, linked, clinical and administrative data of chest pain presentations. METHODS AND RESULTS: We included 192 978 consecutive adult patients (mean age 62 years; 51% female) with acute chest pain without ST-elevation brought via emergency medical services (EMS) to 53 emergency departments in Victoria, Australia (1/1/2015-30/6/2019). From 32 candidate variables, a risk-adjusted logistic regression model for 30-day mortality (C-statistic 0.899) was developed, with excellent calibration in the full cohort and with optimism-adjusted bootstrap internal validation. Annual 30-day RSMR was calculated by dividing each hospital's observed mortality by the expected mortality rate and multiplying it by the annual mean 30-day mortality rate. Hospital performance according to annual 30-day RSMR was lower for outer regional or remote locations and at hospitals without revascularisation capabilities. Hospital rates of angiography or transfer for patients diagnosed with non-ST elevation myocardial infarction (NSTEMI) correlated with annual 30-day RSMR, but no correlations were observed with other existing key performance indicators. CONCLUSION: Annual hospital 30-day RSMR can be feasibly calculated at the symptom-level using routinely collected, linked clinical, and administrative data. This outcome-based metric appears to provide additional information for monitoring hospital performance in comparison with existing process of care key performance measures.