Accepted for/Published in: JMIR Public Health and Surveillance
Date Submitted: Nov 11, 2025
Date Accepted: Jun 17, 2026
Impact of Different COVID-19 Pandemic Phases on Emergency Department Length of Stay and Intensive Care Unit Admission Risk: A Single-Center Retrospective Cohort Study
ABSTRACT
Background:
Since 2020, Corona-virus disease-2019 (COVID-19) has rapidly spread globally, triggering a pandemic and posing a serious threat to human health. Public health emergencies often affect people's behavior and health management habits
Objective:
This study aims to evaluate the impact of different phases of the Corona-virus disease-2019 (COVID-19) pandemic on the management of patients in the emergency department (ED) resuscitation area and the incidence of in-hospital cardiac arrest (IHCA).
Methods:
This is a single-center, retrospective observational cohort study. The management of patients in the ED resuscitation area was compared across three periods: pre-pandemic (January 2019 to December 2019), during the pandemic (January 2021 to December 2021), and post-pandemic (January 2023 to December 2023). The primary outcome was ED length of stay (LOS), with subgroup analyses performed for common acute conditions and hospital disposition outcomes. Stepwise regression was used to determine whether the COVID-19 pandemic independently influenced IHCA.
Results:
Significant differences in ED LOS were observed across the three periods, with an increasing trend (P<0.001). Subgroup analysis revealed that patients with stroke and acute myocardial infarction had significantly prolonged ED LOS during the pandemic compared to pre-pandemic and post-pandemic periods (P<0.05). Admissions to respiratory, infectious disease, and Intensive Care Unit (ICU) showed an increasing trend across the three periods (P<0.001). Regression analysis indicated that the post-pandemic period was an independent risk factor for IHCA in ED patients (adjusted odds ratio[aOR] 1.52; 95% confidence interval [CI] 1.18-1.97; P=0.001).
Conclusions:
The COVID-19 pandemic led to an increase in the number of patients in the ED resuscitation area and a significant prolongation of ED LOS, with varying impacts on common acute conditions and different specialty admissions. The post-pandemic period emerged as an independent risk factor for IHCA events in the ED setting.
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