Intensive care unit and hospital mortality for patients with COVID-19 compared with patients with community-acquired pneumonia during the COVID-19 pandemic in Alberta hospitals: Retrospective observational cohort study

RATIONALE Mortality among hospitalized patients with community-acquired pneumonia (CAP) ranges from 10% to 12%, increasing to approximately 30% in those requiring mechanical ventilation (IMV). During COVID-19, it remained unclear whether critically ill COVID-19 patients experienced different outcomes compared with CAP patients. This study compared ICU and hospital mortality between these groups.OBJECTIVES The objective of this study was to compare demographics, clinical characteristics, and outcomes of adults with COVID-19 admitted to intensive care units (ICUs) in Alberta during the pandemic versus CAP patients.METHODS This retrospective population-based cohort study included adults admitted to 19 medical–surgical ICUs in Alberta, Canada, from March 2020 to March 2023. Data were obtained from Alberta Health Services databases. Multinomial regression estimated adjusted odds ratios (ORs) for co-primary outcomes (ICU and hospital mortality) and secondary outcomes (ICU and hospital readmission).RESULTS A total of 5138 COVID-19 and 5154 CAP ICU admissions were analyzed. CAP admissions were steady, while COVID-19 admissions occurred in four waves. COVID-19 patients had higher ICU mortality (OR 1.20, 95% CI 1.09–1.32; p < 0.001) and ICU readmission (OR 1.32, 95% CI 1.00–1.75; p = 0.048). ICU length of stay and hospital mortality were similar. COVID-19 patients had lower IMV use, shorter hospital length of stay, and lower hospital readmission. Hospital mortality declined more over time among COVID-19 patients (interaction OR 0.984; p < 0.001).CONCLUSIONS COVID-19 was associated with higher ICU mortality, whereas CAP was associated with longer hospitalization. The ICU mortality among mechanically ventilated patients with COVID-19 declined following the RECOVERY trial. However, other evolving therapies, virological, and immunological factors likely contributed to the progressive improvement in survival.