Risk factors for mortality in coronavirus disease 2019 patients with silent hypoxemia.

Objective: To describe the predictors of mortality in hospitalized patients with severe acute respiratory syndrome (SARS) due to COVID-19 presenting with silent hypoxemia.

Material And Methods: Retrospective cohort study of hospitalized patients with SARS due to COVID-19 and silent hypoxemia at admission, in Brazil, from January to June 2021. The primary outcome of interest was in-hospital death. Multivariable logistic regression analysis was performed.

Results: Of 46,102 patients, the mean age was 59 ± 16 years, and 41.6% were female. During hospitalization, 13,149 patients died. Compared to survivors, non-survivors were older (mean age, 66 vs. 56 years; P < 0.001), less frequently female (43.6% vs. 40.9%; P < 0.001), and more likely to have comorbidities (74.3% vs. 56.8%; P < 0.001). Non-survivors had higher needs for invasive mechanical ventilation (42.4% vs. 6.6%; P < 0.001) and intensive care unit admission (56.9% vs. 20%; P < 0.001) compared to survivors. In the multivariable regression analysis, advanced age (OR 1.04; 95%CI 1.037-1.04), presence of comorbidities (OR 1.54; 95%CI 1.47-1.62), cough (OR 0.74; 95%CI 0.71-0.79), respiratory distress (OR 1.32; 95%CI 1.26-1.38), and need for non-invasive respiratory support (OR 0.37; 95%CI 0.35-0.40) remained independently associated with death.

Conclusions: Advanced age, presence of comorbidities, and respiratory distress were independent risk factors for mortality, while cough and requirement for non-invasive respiratory support were independent protective factors against mortality in hospitalized patients due to SARS due to COVID-19 with silent hypoxemia at presentation.