Response.

To the Editor:

We would like to provide responses to the comments by Honore et al in relation to our recent report on spontaneous pneumothorax (SP) in patients with COVID-19.

First, we absolutely agree that, despite the higher mortality rate observed in our cases with respect to control subjects, our report does not preclude any pathophysiologic relationship between COVID-19 and SP, because the latter could just be an additional sign of COVID-19 severity. In fact, due to the limited number of cases, we adjusted mortality rates only for age, sex, and center, but not for comorbidities or disease severity. As Honore et al underline, cases were sicker than control subjects, as suggested by the higher rate of ICU admission and by the fact that patients with COVID-19 and SP more frequently had asthma (as a comorbidity) and dyspnea (as the main complaint) than patients with COVID-19 without SP, which could explain by itself our reported higher mortality rate.

Second, they claim our mortality rate is higher than the mortality rate that they calculated according to two papers that reviewed previous literature. , In the absence of a clear, extensive, and well-designed search strategy, these revisions could provide inaccurate estimations. For example, readers must be aware that these two reviews included several identical patients and that a careful analysis renders only 26 unique cases, with five patients (19.2%) dying during the episode. This mortality rate is not statistically different from that reported in our series (13 deaths in 40 patients; 32.5%; P = .24). Furthermore, some cases in these reviews received noninvasive ventilation and could not correspond to real SP. Therefore, we believe that our unique study with a predefined methods for patient inclusion at ED arrival (before any noninvasive ventilation was initiated) that was included within a grand multicenter project to identify unusual manifestations of COVID-19 , provides a more reliable approach to mortality rates in patients with COVID-19 who are experiencing the development of SP.

Third, although we acknowledge that we did not record prior bullous disease, underlying connective tissue disease, hormonal irregularities, environmental exposure (with the exception of tobacco), and vigorousness of coughing, most of these factors are difficult to measure, and neither have they been evaluated in previous reports of SP in patients with COVID-19.

And last, Honore et al ask how many of our patients underwent rapid surgery. As stated in our original report, a thoracic tube was placed in 29 of the 40 patients (72.5%) to relieve pneumothorax, which is a significantly higher percentage than that observed in patients included in aforementioned reviews (11 of 26 patients; 42.3%; P = .01). This provides additional evidence that our patients were really sick and makes it unlikely that the lack of SP treatment could have influenced our reported high mortality rate, as our colleagues seem to suggest.