Acute Medicine 2018; 17(3): 130-136 130 Original Article © 2018 Rila Publications Ltd. D Byrne, JG Browne, R Conway, S Cournane, D O’Riordan & B Silke Abstract Background: There is concern that undue ED wait times may result in adverse outcomes. Methods: We studied 30-day in-hospital mortality (2002-2017) for all medical admissions (106,586 episodes; 54,928 patients) focusing on clinical risk profile Results: Comparing 2002-09 vs. 2010-17, median ED waits > 6 hours (hr) increased 10h (95% CI: 8,13) to 15h (95% CI: 9,19). 30-day mortality declined 6.2% to 4.9%- (RRR- 20.8%/ NNT- 78). 30-day-mortality by ED wait: - < 4hr 6.6% (95% CI: 6.3%, 6.9%), 4-8hr 4.8% (95% CI: 4.6%, 5.0%), 8-12hr 4.3% (95% CI: 4.1%, 4.5%) or >=12hr 4.2% (95% CI: 3.9%, 4.5%). Conclusion: Admissions with shorter waits are overrepresented with high clinical acuity. Higher Risk Score patient with extended wait times had worse clinical outcomes. Keywords Emergency Department, Wait Times, Acute Illness Severity, Manchester Triage Category. Mortality outcomes and emergency department wait times - the paradox in the capacity limited sytem Introduction The discipline of Acute Medicine investigates and treats urgent clinical conditions that require immediate and specialist management. 1 The immediate outcomes of an emergency medical admission appear to have improved over time; 2 the restructuring of operational systems 3,4 and the establishment of acute medical admissions units (AMAU) 5,6 have contributed to an improvement in clinical outcomes. The USA National Hospital Discharge Survey (NHDS) data from 2000 through 2010 reported that inpatient hospital deaths decreased 8% from 2000 to 2010 7 – an effect size comparable with the outcome improvement we have witnessed. We must remain cognizant of these data when concerns are expressed about Emergency Department (ED) waiting times. We previously reported that longer Emergency Department waiting times were associated with worse 30-day hospital outcomes. 8 The evidence of the relationship between ED waiting times has focused on high acuity patients - where delays in time sensitive treatments for serious conditions might impact on outcomes. 9 Emergency Department wait times have been correlated with an increased risk of death and subsequent hospital admission in patients initially evaluated and discharged from the ED. 9 Of course there are resource constraints to population health care funding and in this paper we focus on a paradox – improving clinical outcomes at a time of deterioration in acute hospital capacity with increasing wait time across the acute hospital system. Ireland has 3.1 acute hospital beds/ 1000 of the population versus a European average of 5.3/1000; for a population of 4.7 million, this implies an approximate 10,000 acute bed capacity deficit. An Irish Department of Health strategy document (the Codd report) recognised the immediate need in 2002 for 1500 new beds with 6000 further beds before 2006. 10 At that time, 23 hospitals were found to have occupancy levels of greater than the functionally ideal rate of 85% with an average occupancy level of 95%. However, the collapse of the Irish economy resulted in serious austerity with health service spending especially targeted with reduced absolute spend over nearly a decade. Such parsimony was likely to have consequence and demographic trends and increased demand have created a capacity problem with year on year increases in ED wait numbers across the state. Clearly risk management then results in the sickest patients receiving priority for immediate access to beds – this raises the possibility that shorter wait times would be over represented with seriously ill patients who would have worse outcomes. We therefore have investigated the relationship between ED wait times and clinical outcomes (30-day hospital episode mortality) for emergency medical admissions (>105,000) between the years 2002-2017. We look at the interaction between clinical acuity as measured by the Manchester Triage system 11 and the clinical Risk Score 12 of each admission. Methods Background St James’s Hospital, Dublin serves as a secondary care centre for emergency admissions in a catchment area with a population of 270,000 adults. All emergency Declan Byrne 1 MB MSc FRCPI Joseph G Browne 1 MD MRCPI Richard Conway 1 MD MRCPI Seán Cournane 2 PhD Deirdre O’Riordan 1 MD FRCPI Bernard Silke 1 MD DSc FRCPI 1 Department of Internal Medicine 2 Medical Physics and Bioengineering Department, St James’s Hospital, Dublin 8, Ireland. Correspondence Declan Byrne Department of Internal Medicine, St James’s Hospital, Dublin 8, Ireland EMail: debyrne@stjames.ie