Effect of a Multi-Diagnosis Observation Unit on Emergency Department Length of Stay and Inpatient Admission Rate at Two Canadian Hospitals.

Background: Observation units (OUs) have been shown to reduce emergency department (ED) lengths of stay (LOS) and admissions. Most published studies have been on OUs managing single complaints.

Objective: Our aim was to determine whether an OU reduces ED LOS and hospital admission rates for adults with a variety of presenting complaints.

Methods: We comparatively evaluated two hospitals in British Columbia, Canada (hereafter ED A and ED B) using a pre-post design. Data were extracted from administrative databases. The post-OU cohort included all adults presenting 6 months after OU implementation. The pre-OU cohort included all adults presenting in the same 6-month period 1 year before OU implementation.

Results: There were 109,625 patient visits during the study period. Of the 56,832 visits during the post-OU period (27,512 to ED A and 29,318 to ED B), 1.9% were managed in the OU in ED A and 1.4% in ED B. Implementation was associated with an increase in the median ED LOS at ED A (179.0 min pre vs. 192.0 min post [+13.0 min]; p < 0.001; mean difference -12.5 min, 95% confidence interval [CI] -15.2 to -9.9 min), but no change at ED B (182.0 min pre vs. 182.0 min post; p = 0.55; mean difference +2.0 min, 95% CI -0.7 to +4.7 min). Implementation significantly decreased the hospital admission rate for ED A (17.8% pre to 17.0% post [-0.8%], 95% CI -0.18% to 0.15%; p < 0.05) and did not significantly change the hospital admission rate at ED B (18.9% pre to 18.3% post [-0.6%], 95% CI -1.19% to -0.09%; p = 0.09).

Conclusions: A multi-diagnosis OU can reduce hospital admission rate in a site-specific manner. In contrast to previous studies, we did not find that an OU reduced ED LOS. Further research is needed to determine whether OUs can reduce ED overcrowding.