Characteristics and predictors of severe outcomes of COVID-19 cases presenting to the emergency department of a major Australian referral hospital: A record linkage study

Abstract

Objective

To describe the characteristics, outcomes and predictors of a severe outcome of patients presenting with a SARS-CoV-2 infection to the ED of a major urban referral hospital in New South Wales, Australia, from January 2020 through February 2022.

Methods

Linked healthcare and death registration records were used and included any person assigned a diagnosis potentially related to an acute respiratory infection in the ED and that had a linked positive COVID-19 detection. Logistic regression was used to determine predictors of a severe outcome (ICU admission or death) within 28 days.

Results

Of 2081 included COVID-19 patients, 238 (11.4%) had a severe outcome within 28 days of arrival at the ED. Among adults, the odds of a severe outcome increased with age, although the rate of increase in odds within age groups was statistically significant only in 30–64-year-olds (4% per year of age; confidence interval [CI] 2–6). Ambulance arrival (odds ratio [OR] 2.85; CI 1.76–4.78), higher triage urgency (category 1 or 2 compared with 4 or 5: OR 8.63; CI 4.41–18.12), and presentation during the pre-Delta (OR 6.18; CI 3.59–10.66) and Delta (OR 3.64; 95% CI 2.49–5.35) variant periods (compared with Omicron) were independently associated with increased risk of a severe outcome.

Conclusion

Age, ambulance arrival, higher triaged urgency, and presentation earlier in the pandemic were predictors of a severe COVID-19 outcome. Aged care measures and prioritising vaccination of older persons and aged care workers may have reduced severe outcomes in the elderly.