Background: Observation Units (OUs) are a common healthcare delivery model for health systems across the United States. OUs vary from a type 1 to type 4 based on several factors[1]. Another category of OUs – second-level OUs – does not fit this traditional classification due to a different patient population composition and staffing model. The impact of a second-level OU in the setting of a coexisting type I OU has not been previously evaluated. Therefore, our study assesses the impact of patient outcomes in a second-level OU with a coexisting type 1 OU at a large academic institution[2].

Purpose: The purpose of this study was to measure the impact of a new Second-Level OU on admission rates and length of stay. Admission rate was defined as the incidence of patient conversion from observation status to inpatient status.

Description: We established a second-level OU comprised of 14-beds on a medical-surgical floor. Patients designated as observation status who did not meet the criteria for the type 1 OU in the Emergency Department were cohorted on this unit and cared for by a multidisciplinary team including nurses, case managers, pharmacists, and hospital medicine (HM) providers. We compared patient outcomes pre- and post-second-level OU implementation for all observation status patients admitted to HM between January 1, 2019 and December 31, 2019. The study was designed to assess three implementation phases during which the OU was being established and improved. For examining the data, three different groups of patients were compared: Group 1 included patients admitted under observation status before implementation of OU; Group 2 included patients admitted under observation status to non-OU after implementation of OU; and Group 3 included patients admitted under observation status to OU after implementation of OU. A total of 2180 patients were included in the analysis of admission rate (i.e. incidence rate of patient conversion from observation to inpatient status). Analysis of the data revealed that admission rate was significantly lower in Group 3 (26.2%) when compared to Group 1 (37.8%) and Group 2 (42.1%) (p-value < 0.0001). For the LOS analysis, there were 1480 patients included. The sample size for Groups 1, 2 and 3 were 435, 234, and 811, respectively with the majority of patients presenting from the ED and discharging to home. There was no significant differences noted between gender, age or payor source between Groups 1, 2, and 3. The mean LOS was 55.5 hours [CI 51.1 – 59.8] for Group 1; 61.3 [55.2 – 67.4] hours for Group 2; and 38.8 hours [37.4 – 40.2] for Group 3. This reduction in LOS between the groups was statistically significant with a p-value of < 0.0001.

Conclusions: In conclusion, this was the first study to assess the impact of patient outcomes in a second-level OU with a coexisting type 1 OU. We found a significant decrease in mean LOS, admission rate and bed-days. However, further research is needed to evaluate the specific factors influencing the LOS in each individual type of OU.

IMAGE 1: Table 1: showing Admission Rates

IMAGE 2: Table 2. Multivariate adjusted linear regression model predicting increase length of stay (LOS) for Groups 1-3.