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.