Severe forms of COVID-19 among patients with chronic respiratory diseases: be attentive to the severity of the underlying respiratory impairment.

Dear Editor, we appreciate Ausset et al., consideration of our study in their letter reminding us of the very recent literature related to a protective role of chronic respiratory diseases, especially asthma and chronic obstructive pulmonary disease (COPD). As stated in the letter, the meta-analysis by Rogliani et al., included 8476 hospitalized patients for SARS-CoV-2 infection and found that patients with asthma and COPD were at reduced risk of hospitalization [1]. Another meta-analysis showed opposite results [2]. These data should be interpreted with great caution as they do not consider the severity of the underlying respiratory disease. Indeed and as well explained in the letter by Ausset et al., it is now clear that patients with the most severe form of asthma and COPD have a high risk of developing a severe form of COVID-19 (i.e., requiring invasive mechanical ventilation) [3]. Our results are consistent with this since, as mentioned in our article, our population did not include patients with severe asthma and only three patients with COPD had long-term oxygen therapy.

The letter by Ausset et al., also has the merit of summarizing the literature in favor of a protective role for inhaled corticosteroids (ICS) in SARS-CoV-2 pneumonia. Most of the quoted articles only included outpatients without specifically addressing patients with chronic respiratory diseases. The novelty of our study is to have included patients hospitalized in the COVID-19 ward and accurately characterize patients with COPD or asthma. As stated by Ausset et al. in their letter, a randomized controlled and multicentric trial included 4700 outpatients at high risk of complications with a recent COVID-19 infection and revealed that ICS improved time to recovery [4]. A recent meta-analysis supported the benefit of ICS in resolving clinical symptoms in non-hospitalized patients with COVID-19 [5]. In contrast, in a post-hoc analysis of over 8 million patients, two or more prescriptions of ICS led to a slightly higher risk of severe COVID-19 [6]. As hypothesized in our article, ICS may have potential clinical effect in SARS-CoV-2 infection through various pathophysiological mechanisms. For example, Milne et al. demonstrated a downregulation of the expression of genes involved in SARS-CoV-2 infection in bronchial epithelial cells of patients with COPD by budesonide [7]. However, the clinical relevance of these in vitro findings remains to be clarified.

In conclusion, on the one hand, asthma and COPD seem to protect against COVID-19 depending on the severity of the underlying chronic respiratory disease. On the other hand, ICS could have a protective role but only the results of ongoing randomized controlled trials will confirm this hypothesis.

Declaration of Competing Interest

None.