Emergency Department Crowding and Outcomes After Emergency Department Discharge

Abstract

Study objective We assess whether a panel of emergency department (ED) crowding measures, including 2 reported by the Centers for Medicare & Medicaid Services (CMS), is associated with inpatient admission and death within 7 days of ED discharge. Methods We conducted a retrospective cohort study of ED discharges, using data from an integrated health system for 2008 to 2010. We assessed patient transit-level (n=3) and ED system-level (n=6) measures of crowding, using multivariable logistic regression models. The outcome measures were inpatient admission or death within 7 days of ED discharge. We defined a clinically important association by assessing the relative risk ratio and 95% confidence interval (CI) difference and also compared risks at the 99th percentile and median value of each measure. Results The study cohort contained a total of 625,096 visits to 12 EDs. There were 16,957 (2.7%) admissions and 328 (0.05%) deaths within 7 days. Only 2 measures, both of which were patient transit measures, were associated with the outcome. Compared with a median evaluation time of 2.2 hours, the evaluation time of 10.8 hours (99th percentile) was associated with a relative risk of 3.9 (95% CI 3.7 to 4.1) of an admission. Compared with a median ED length of stay (a CMS measure) of 2.8 hours, the 99th percentile ED length of stay of 11.6 hours was associated with a relative risk of 3.5 (95% CI 3.3 to 3.7) of admission. No system measure of ED crowding was associated with outcomes. Conclusion Our findings suggest that ED length of stay is a proxy for unmeasured differences in case mix and challenge the validity of the CMS metric as a safety measure for discharged patients.

Impact of emergency department occupancy on waiting times, rates of admission and representation, and length of stay when hospitalised: A data linkage study

“…These outcomes were selected as they represent either a key time sensitive service delivery measure (waiting time), or measures that may reflect worsening of conditions while waiting for treatment (to the extent that admission is required or that LOS when admitted is extended) or adverse events after departure (28 day representation, which is related to the NSW Health Key Performance Indicator of unplanned admissions within 28 days of separation). These outcomes are also consistent with existing literature . ED waiting time was defined as the difference between the time of arrival to the ED and the time first attended to by the treating doctor or nurse under the clinical supervision of a doctor .…”

“…The main study factor was volume of patients in an ED during the hour interval in which patients presented to the ED, representing an ED‐system measure of occupancy. This ED‐system measure of occupancy was adapted from Gabayan et al ., and was calculated as the total number of patient‐hours spent in the ED for each hour interval. As an example, if, during a 1 h interval, five patients were present in an ED for the full hour and another five patients each spent 30 min in the ED then the total patient‐hours for that 1 h interval would be 7.5 h. A main point of difference between our measure of ED occupancy and that operationalised in Gabayan et al .…”

The safety of emergency medicine

“…Data suggest that less than 5% of all return visits are associated with a safety incident. More recently, LOS has been challenged as a safety metric56 underlining the need for a fuller understanding of indicators and potential high-impact interventions.…”

Prevalence of Crowding, Boarding and Staffing Levels in Swedish Emergency Departments - a National Cross Sectional Study

“…Crowding has been linked to increased inpatient mortality and decreased quality of care [3][4][5][6]. Many investigations have been conducted at a single ED or in local health care systems, with large variations in the extent of crowding, and nationwide data are lacking [6][7][8].…”