Early Oxygen Therapy may be Beneficial to Patients with COVID-19 and Underlying Pulmonary Diseases

We read with great interest the findings of the study reported by Cornwell et al. [1], which investigated the risks of severe illness among patients hospitalized with COVID-19 and underlying asthma and/or COPD. As reported in the study [1], patients hospitalized with COVID-19 and underlying asthma had significantly higher risk of mortality (adjusted risk ratio = 5.56; 95% confidence interval 4.89 to 6.32), compared to those hospitalized without COVID-19. Similarly, patients hospitalized with COVID-19 and underlying COPD had significantly higher risk of mortality (adjusted risk ratio = 3.53; 95% confidence interval 3.44 to 3.62), compared to their counterparts who were without COVID-19. Indeed, the findings of the study [1] resonate the findings of another multinational study [2], which reported that the patients with COVID-19 and underlying pulmonary diseases had a higher risk of 30-day all-cause mortality (hazard ratio = 1.78; 95% confidence interval 1.58 to 2.01), compared to their counterparts who were without underlying pulmonary diseases. In multivariable analysis, hypoxemia (i.e. oxygen saturation of less than 92%) on admission is one of the factors independently associated with the risk of all-cause mortality in patients with COVID-19 and underlying pulmonary diseases (hazard ratio = 4.35; 95% confidence interval 3.08 to 6.15) [2]. We believe there are implications to the findings where the authors did not highlight in the article, especially in light of the recent understandings on the pathogenesis of COVID-19. Of late, the impact of oxygen saturation on B cells in patients with COVID-19 has been reported [3]. It was observed that patients with a severe course of COVID-19 demonstrated significant and persistent B cell abnormalities, including reduced marginal zone-like, memory and transitional B cells, which can be associated with hypoxia-related transcriptional changes in B cells [3]. Indeed, similar B cell abnormalities had been observed in animal models that remained in hypoxic conditions [3]. Therefore, the fact that hypoxemia on admission was associated with the risk of mortality in patients with COVID-19 and underlying pulmonary diseases, may be due at least in part to the B cell deficits from hypoxia. B cell deficits could contribute to the pathogenesis of COVID-19 by reducing early antigen transportation and presentation or cytokine production [4]. Additionally, B cell deficits could also predispose the occurrence of secondary bacterial infection [5]. Therefore, to reduce the risk of mortality in patients with COVID-19 and underlying asthma and/or COPD, we believe that early oxygen therapy should be administered, preferably upon admission, to prevent perturbations to B cell immunity, which could impact the clinical outcomes. This is especially of great importance since patients with underlying asthma and/or COPD can be more prone to hypoxia/hypoxemia with the acquisition of COVID-19. Moreover, measured oxygen saturation may underestimate tissue hypoxia, which can be sustained for an extended period of time before hospitalization [6]. We believe such an approach is worthy of more clinical investigations to determine if it improves the prognosis of patients with COVID-19 and underlying pulmonary diseases.