Treatment outcomes in Polish COVID-19 patients requiring hospitalisation in the intensive care unit: a single-centre retrospective study

Introduction
COVID-19 has disturbed the functioning of Polish healthcare for the past two years. Due to the high proportion of patients requiring admission to the intensive care unit (ICU), these wards are particularly overwhelmed and are considered the bottleneck of the healthcare system. The aim of this study was to describe clinical outcomes of critically ill patients treated in a single tertiary ICU in Poland, assess factors associated with mortality and compare outcomes of patients treated during the 2nd and 3rd waves of the pandemic.

Material and methods
This is a retrospective single-centre study including patients admitted to the ICU between October 2020 and May 2021 (the 3rd wave) with confirmed SARS-CoV-2 infection. Patients were followed up until death or 90 days after ICU admission. The co-primary endpoints of this study included ICU, 30-day and 90-day mortality.

Results
We enrolled 108 patients at a mean age of 64.3 (SD = 12) years, the majority of whom were male (63.9%). Mortality in the ICU, after 30 days and 90 days was 44.4% (48/108), 50.0% (54/108), and 57.9% (62/108), respectively. Mortality at 90 days was associated with increasing age (OR = 3.97, 95% CI: 1.87–8.41) and was significantly higher during the 2nd wave (65.6 vs. 46.5%, log-rank P = 0.043) compared to the 3rd wave of the pandemic.

Conclusions
This retrospective single-centre study confirms the high mortality rate among critically ill patients with COVID-19. Moreover, it suggests a significant association between 90-day mortality and increasing age as well as differences in mortality between the 2nd and 3rd waves of the pandemic in Poland.