Patients with COVID-19 admitted to very busy intensive care units (ICUs) have significantly increased mortality risk compared with being admitted during normal or low occupancy, according to a national retrospective observational cohort study spanning the first wave of the pandemic.
The pre-print study, published on MedRxiv, analysed data from 4032 adult patients with COVID-19 who were admitted to ICU across 114 hospital trusts in England between April and June 2020.
Researchers studied patient ICU outcomes and assessed the effect of availability of beds with access to mechanical ventilators. Results were adjusted for unit characteristics (pre-pandemic size), individual patient-level demographic characteristics and recorded comorbidities.
A total of 1548 (38.4%) patients from the cohort died. Adjusted mortality was 19 per cent higher for admissions during periods of high occupancy; classed as >85 per cent occupancy versus baseline of 45-85 per cent (median OR, 1.19; 95% posterior credible interval (PCI), 1.00-1.44).
In contrast, mortality was decreased by 25 per cent for admissions during low occupancy, classed as
Study author Dr Bilal Mateen said: “To put into context as to why these results are so important - at the end of 2020, 37 of 123 recorded NHS trusts were experiencing over 85 ICU bed occupancy; 11 of these were completely full and the situation has only got more extreme."
“Our results show the association between risk of death and bed occupancy is linear and as occupancy increases the worse patients' outcomes become. In the worst-case scenario (when mechanical ventilator ICU occupancy goes from zero to 100%) a patient's risk of death nearly doubles, which suggests that every % counts and hospital strain must be reduced.”