Impact of varying wave periods of COVID-19 on in-hospital mortality and length of stay for admission through emergency department: A territory-wide observational cohort study.

BACKGROUND: The COVID-19 pandemic has been associated with excess mortality and reduced emergency department attendance. However, the effect of varying wave periods of COVID-19 on in-hospital mortality and length of stay (LOS) for non-COVID disease for non-COVID diseases remains unexplored. METHODS: We examined a territory-wide observational cohort of 563,680 emergency admissions between January 1 and November 30, 2020, and 709,583 emergency admissions during the same 2019 period in Hong Kong, China. Differences in 28-day in-hospital mortality risk and LOS due to COVID-19 were evaluated. RESULTS: The cumulative incidence of 28-day in-hospital mortality increased overall from 2.9% in 2019 to 3.6% in 2020 (adjusted hazard ratio [aHR] = 1.22, 95% CI 1.20 to 1.25). The aHR was higher among patients with lower respiratory tract infection (aHR: 1.30 95% CI 1.26 to 1.34), airway disease (aHR: 1.35 95% CI 1.22 to 1.49), and mental disorders (aHR: 1.26 95% CI 1.15 to 1.37). Mortality risk in the first- and third-wave periods was significantly greater than that in the inter-wave period (p-interaction < 0.001). The overall average LOS in the pandemic year was significantly shorter than that in 2019 (Mean difference = -0.40 days; 95% CI -0.43 to -0.36). Patients with mental disorders and cerebrovascular disease in 2020 had a 3.91-day and 2.78-day shorter LOS than those in 2019, respectively. CONCLUSIONS: Increased risk of in-hospital deaths was observed overall and by all major subgroups of disease during the pandemic period. Together with significantly reduced LOS for patients with mental disorders and cerebrovascular disease, this study shows the spillover effect of the COVID-19 pandemic.

Changes in Emergency Department Visits, Diagnostic Groups, and 28-Day Mortality Associated With the COVID-19 Pandemic: A Territory-Wide, Retrospective, Cohort Study.

STUDY OBJECTIVE: We aimed to evaluate and characterize the scale and relationships of emergency department (ED) visits and excess mortality associated with the early phase of the COVID-19 pandemic in the territory of Hong Kong. METHODS: We conducted a territory-wide, retrospective cohort study to compare ED visits and the related impact of the COVID-19 pandemic on mortality. All ED visits at 18 public acute hospitals in Hong Kong between January 1 and August 31 of 2019 (n=1,426,259) and 2020 (n=1,035,562) were included. The primary outcome was all-cause mortality in the 28 days following an ED visit. The secondary outcomes were weekly number of ED visits and diagnosis-specific mortality. RESULTS: ED visits decreased by 27.4%, from 1,426,259 in 2019 to 1,035,562 in 2020. Overall period mortality increased from 28,686 (2.0%) in 2019 to 29,737 (2.9%) in 2020. The adjusted odds ratio for 28-day, all-cause mortality in the pandemic period of 2020 relative to 2019 was 1.26 (95% confidence interval 1.24 to 1.28). Both sexes, age more than 45 years, all triage categories, all social classes, all ED visit periods, epilepsy (odds ratio 1.58, 95% confidence interval 1.20 to 2.07), lower respiratory tract infection, and airway disease had higher adjusted ORs for all-cause mortality. CONCLUSION: A significant reduction in ED visits in the first 8 months of the COVID-19 pandemic was associated with an increase in deaths certified in the ED. The government must make provisions to encourage patients with alarming symptoms, mental health conditions, and comorbidities to seek timely emergency care, regardless of the pandemic.