The risk of dying in hospital from COVID-19 was highest during the third wave of the pandemic in Australia, new research has revealed.
The study, led by Monash University, examined evolving patent characteristics, treatments and outcomes of critically ill patients during the first, second and third waves of COVID-19 in Australia, drawing data from SPRINT-SARI Australia, a hospital-based surveillance database that allows real-time tracking and reporting of the sickest patients with COVID-19 in hospitals and Intensive Care Units.
Research found 2,493 people were admitted to 59 ICUs – 214 during the first wave (9%), 296 during the second (12%) and 1,983 (80%) during the third wave.
Of these patients, 30 died in hospitals during the first wave, 35 during the second and 281 during the third.
Patients admitted to ICU during the third wave were mostly unvaccinated (75%), younger than the previous two waves, more likely to be pregnant and/or obese, and less likely to have co-morbid conditions, the study, published in the Medical Journal of Australia, found.
While the length of ICU and hospital stay decreased during the third wave, the risk of dying increased. Although fewer ICU patients received invasive respiratory therapies, the rise in in-hospital mortality risk was primarily seen in patients who had received mechanical ventilation.
Researchers point out that there were relatively few infections in Australia during waves one and two due to the combination of a national quarantine and social distancing measures. However, the emergence of the Delta strain in mid-2021 reduced the effectiveness of these measures, increasing community spread.
They say the third wave was notable for greater use of non-invasive respiratory support over mechanical ventilation, awake and invasive prone positioning (lying patients on their front during mechanical ventilation), disease-specific pharmacological therapies which affect the immune system, and increased occupancy of COVID-19 patients in ICUs.
“There was widespread adoption of new evidence-based practices. However, despite these differences, the risk of dying was higher in the third wave and the findings reinforce the need to adequately resource ICUs, particularly during peak demand,” senior author Dr Aidan Burrell, from the Monash School of Public Health and Preventive Medicine, said.
“While other complications were reduced, notably bacteraemia, deep vein thrombosis, myocarditis and chronic cardiac failure – factors commonly associated with an increased risk of death, other complications were more common in the third wave, such as the higher rate of bacterial pneumonia and pulmonary embolism.”
Read the full paper here
