ED crowding is associated with inpatient mortality among critically ill patients admitted via the ED: Post hoc analysis from a retrospective study

Background Adverse effects of emergency department (ED) crowding among critically ill patients are not well known. Objectives We evaluated the association between ED crowding and inpatient mortality among critically ill patients admitted via the ED, and analyzed subsets of patients according to admission diagnosis. Methods We performed a post hoc analysis using data from a previous retrospective study. We enrolled admitted patients via the ED with an initial systolic blood pressure of 90 mm Hg or lower when presenting to the ED. The ED occupancy ratio was used as a measure of crowding. The primary outcome was inpatient mortality. Multivariable logistic regression models adjusted for potential confounding variables were constructed for the entire cohort and for subsets according to admission diagnosis (infection, cardiac and vascular disease, trauma, gastrointestinal bleeding, and other factors). Results A total of 1801 patients were enrolled, with a mortality rate of 14.6% (262 patients). The mortality rate by ED occupancy ratio quartile was 9.7% for the first quartile, 15.9% for the second quartile, 18.2% for the third quartile, and 14.4% for the fourth quartile. This resulted in adjusted odds ratios of 1.95, 2.51, and 1.93 and corresponding 95% confidence intervals of 1.23-3.12, 1.58-3.99, and 1.21-3.09 for the second, third, and fourth quartiles, respectively, compared with the first quartile. The effect of ED crowding was highest in the trauma subset, followed by the infection subset, whereas ED crowding did not appear to have any effect on the cardiac and vascular disease subsets. Conclusion Emergency department crowding was associated with increased inpatient mortality among critically ill patients admitted via the ED.