Mortality in patients with COVID-19 versus non-COVID-19- related acute respiratory distress syndrome: A single center retrospective observational cohort study

The pathophysiology of coronavirus disease-2019 (COVID-19)-related acute respiratory distress syndrome (ARDS) varies from other pneumonia-related ARDS. We evaluated whether the mortality rates differed for COVID-19 and non-COVID-19-related ARDS in the Asian population in 2021. This single center retrospective observational cohort study included patients with COVID-19 and non-COVID-19-related ARDS that required invasive mechanical ventilation. The primary outcome was all-cause in-hospital mortality. The secondary outcomes included hospital length of stay, ICU length of stay, duration of mechanical ventilation, and ventilator-free days (VFDs) during the first 28 days. A 1:1 propensity score matching was performed to correct potential confounders by age, obesity or not, and ARDS severity. One-hundred-and-sixty-four patients fulfilled the inclusion criteria. After 1:1 propensity score matching, there were 50 patients in each group. The all-cause in-hospital mortality of all patients was 38 (38%), and no significant differences were found between COVID-19 and non-COVID-19-related ARDS (17 [34%) vs. 21 [42%], p = 0.410). Both groups had length of stay (30.0 [20.0–46.0] vs. 27.0 [13.0–45.0] days, p = 0.312), ICU length of stay (19.0 [13.0–35.0] vs. 16.0 [10.0–32.0] days, p = 0.249), length of mechanical ventilation (19.0 [10.0–36.0] vs. 14.0 [9.0–29.0] days, p = 0.488), and ventilator-free days during the first 28 days (5.5 [0.0–17.0] vs. 0.0 [0.0–14.0] days, p = 0.320). Immunocompromised status (Hazard ratio: 3.63; 95% CI: 1.51–8.74, p = 0.004) and progress to severe ARDS (Hazard ratio: 2.92; 95% CI: 1.18–7.22, p = 0.020) were significant in-hospital mortality-related confounders. There were no significant difference in mortality among both groups. Immunocompromised status and progression to severe ARDS are two possible risk factors for patients with ARDS; COVID-19 is not a mortality-related risk exposure.