Trends in Observation Care and the Growth of Dedicated Emergency Department Observation Units: An Analysis of the National Hospital Ambulatory Medical Care Survey, 2007-2022.

OBJECTIVES

We examined changes in observation care from 2007 to 2022 and compared emergency departments (EDs) with ED observation units (EDOUs) to EDs with other observation care settings.

METHODS

We analyzed 2007-2022 National Hospital Ambulatory Medical Care Survey data. We examined the proportion of ED visits resulting in hospitalizations (both inpatient and observation admits) and observation stays. We also examined the proportion of EDs reporting the presence of EDOUs and observation units outside the ED (hospital observation units or HOUs). Lastly, we compared patient populations across observation care settings.

RESULTS

From 2007 to 2022, the overall hospitalization rates among sampled ED visits were 14.5% (95% CI, 13.6-15.7) in 2007-2008 and 13.8% (95% CI, 12.9-15.8) in 2021-2022. Observation rates were 2.0% (95% CI, 1.6-2.4) to 2.4% (95% CI, 1.8-3.2) over the same periods (annual trend = 0.051). The proportions of hospitals reporting OUs were 34.3% (95% CI, 27.9-40.6) in 2007-2008 and 42.7% (95% CI, 35.2-50.6) in 2021-2022, with EDOU increasing from 19.2% (95% CI, 14.7-24.7) to 30.8% (95% CI, 24.3-38.2) contemporaneously. Compared to other EDs, EDs with EDOUs had higher proportions of Medicaid-covered patients among those who received observation care, but lower rates of subsequent inpatient stay after observation.

CONCLUSION

From 2007 to 2022, there was a modest increase in observation care utilization but a substantial increase in the presence of EDOUs across US EDs. EDOUs also have a lower rate of subsequent inpatient admission. Future research should include observation stays when examining hospital care utilization and seeking to distinguish EDOU from other forms of observation care.