Hospital admission from the emergency department for selected emergent diagnoses during the first year of the COVID-19 pandemic in Ontario: a retrospective population-based study.

Background: Avoidance of care during the pandemic may have contributed to delays in care, and as a result, worse patient outcomes. We evaluated markers of illness acuity on presentation to the emergency department among patients with non-COVID-19-related emergent diagnoses and associated outcomes.

Methods: We conducted a retrospective study using linked administrative data from Ontario. We selected 4 emergent diagnoses, namely appendicitis, ectopic pregnancy, renal failure and diabetic ketoacidosis. We used the nonemergent diagnosis of cellulitis as a control. Our primary outcome of interest was hospital admission. Secondary outcomes were ambulance arrival, surgical intervention, subsequent hospital admission within 30 days of discharge from the emergency department or hospital and 30-day mortality. We compared outcomes during the first year of the COVID-19 pandemic (Mar. 15-Dec. 31, 2020) with a control period (Mar. 15-Dec. 31, 2018, and Mar. 15-Dec. 31, 2019).

Results: Emergency department visits for all conditions initially decreased during the pandemic. During this period, patients across all study diagnoses were more likely to arrive to the emergency department via ambulance. Patients with an ectopic pregnancy had higher odds of surgery in the pandemic period (odds ratio [OR] 1.27, 95% confidence interval [CI] 1.04-1.55) but this was not observed among patients with appendicitis. Patients with renal failure had increased odds of hospital admission (OR 1.14, 95% CI 1.04-1.24) and 30-day mortality (OR 1.17, 95% CI 1.04-1.31) during the pandemic period.

Interpretation: The pandemic period was associated with increased arrival to the emergency department via ambulance across all study diagnoses. Although patients with renal failure had increased hospital admission and death, and patients with ectopic pregnancy had an increased risk of surgery, there were no differences in outcomes for other populations, suggesting the health care system was able to care for these patients effectively.