In this Brief Cutting Edge Report, the authors explored the association between obesity, measured with body mass index (BMI), and severe acute respiratory syndrome coronavirus-2 (SARS-Cov-2) requiring invasive mechanical ventilation. The article, which is clear and well written, address a problem of great relevance in an unprecedented health crisis. The role of obesity is of a great relevance, especially given the burden it poses to the individual and healthcare systems. I have some small comments to do. However, it should be noted that the assessment of obesity via BMI shows several limitations. BMI is not a direct measure of adiposity since its numerator, body weight, is the result of fat free mass and fat mass. What is more, the BMI cut-offs are based on young and middle-aged people and are not indeed adequate for older people.

Minor points Introduction 1. Page 4; line N/A: I suggest removing “Moreover,” at the beginning of the sentence (i.e., before abdominal obesity is associated with impaired ventilation of the base of the lungs, resulting in reduced oxygen saturation of blood.”) Conclusion 2. Page 8; line N/A: This sentence needs rephrasing as does not flow well: “In conclusion, this cohort study showed that obesity is a factor in disease severity of SARS-CoV-2, having greatest impact in patients with a BMI ≥35 kg/m2.”