Impact of the peak period of coronavirus disease 2019 on 28‐day mortality, emergency department visits and length of hospital stay of emergency admissions: A single center retrospective observational study in Hong Kong

Abstract Background During the fifth wave of COVID‐19, accident and emergency departments in Hong Kong experienced significant overcrowding yet there was limited evidence available regarding emergency services and patients' clinical outcomes. The aim of this study was to compare the 28‐day mortality, emergency department (ED) visits, and length of stay (LOS) between the peak period of COVID‐19 and a control period in 2019. Method This was a retrospective case‐control study comparing the peak period of COVID‐19 (7 Feb 2022 to 23 Apr 2022) with a control period (7 Feb 2019 to 23 Apr 2019). Patients' characteristics, ED visits, diagnoses, mortality, and LOS were compared. Results 35,429 patients were included. The 28‐day in‐hospital mortality was significantly higher in the peak period of COVID‐19 with a risk ratio of 3.91 (95% CI: 3.38–4.53). There was a 36% reduction in ED visits during the peak period of COVID‐19 while there was a 53.7% increase in critical cases at triage. The average LOS of emergency admissions increased from 3.8 days (Median = 2.0; IQR = 1.0–3.0) in the control period to 5.1 days (Median = 2.0; IQR = 1.0–6.0) in the peak period of COVID‐19 especially in the subgroups of chronic kidney disease, influenza and pneumonia, diabetes, and mental disorders. Conclusion Increased risk of all‐cause 28‐day in‐hospital deaths was observed during the peak period of COVID‐19 along with a reduction in overall ED visits and lengthened LOS.