In-hospital mortality in patients admitted to Australian intensive care units with COVID-19 between 2020 and 2024.

OBJECTIVE

To describe and compare the demographics, management, and outcomes for patients with COVID-19 admitted to intensive care units (ICUs) in Australia across the various waves of the COVID pandemic.

DESIGN SETTING AND PARTICIPANTS

People aged ≥16 years who were admitted to a participating ICU with confirmed COVID-19 in the Short Period Incidence Study of Severe Acute Respiratory Infection (SPRINT-SARI) Australia study between February 2020 and May 2024.

MAIN OUTCOME MEASURES

Primary outcome: In-hospital mortality. Secondary outcomes: ICU mortality; ICU and hospital lengths of stay; supportive and disease-specific therapies.

RESULTS

From 27 February 2020 to 18 May 2024, 10171 people were admitted to 72 ICUs with confirmed COVID-19 disease. The ave included 518 (5.1%) patients, the wave 2467 (24.3%) patients, and the wave 7186 (70.7%) patients. The median (IQR) age was 61 (49-70) years, 54 (41-66) years, and 65 (45-75) years, respectively (P < 0.001). The proportion of vaccinated cases increased in successive waves (1% vs 23.9% vs 65.1%) but plateaued in the subvariant waves (range 60.0%-71.9%). Invasive mechanical ventilation use decreased across successive waves (52.5% vs 43.6% vs 31.7%, P < 0.001). Use of extracorporeal membrane oxygenation was highest during the wave (3.6%, 83 patients, median duration 18 days [IQR 9.8-35]). Multivariable analysis demonstrated an increased risk of in-hospital mortality among patients admitted during the D (adjusted HR 1.80, 95% CI: 1.38-2.35,  < 0.001) and (adjusted HR 1.88, 95% CI: 1.46-2.42,  < 0.001) waves when compared to the wave.

CONCLUSION

COVID-19 continues to manifest significant morbidity and mortality in those requiring ICU admission. Despite a reduced need for ICU level supports, patients admitted during the wave demonstrated the highest in-hospital mortality.