Shyamali Dharmage (@sdharmage.bsky.social)

Loss of Lung Function Led to Loss of Life during the COVID-19 Pandemic | American Journal of Respiratory and Critical Care Medicine Over 7 million persons across the world died during the COVID-19 pandemic, with most dying of severe pneumonia and respiratory failure (1). According to the Centers for Disease Control and Prevention, the strongest known risk factors for severe COVID-19 and mortality were advanced age; obesity; and comorbidities, including chronic lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), bronchiectasis, interstitial lung disease, pulmonary embolism, and pulmonary hypertension (2). However, this conclusion is based largely on data from methodologically “weak” studies that contained small sample sizes or used suboptimal study designs (e.g., cross-sectional and case-control studies, convenience sampling, retrospective cohorts), making results susceptible to distortions and biases. This may also explain the marked inconsistencies in findings across studies. For example, in COPD, a systematic review of 59 studies found that, on average, patients had a two- to fourfold increase in the risk of severe COVID-19, including mortality, compared with individuals without COPD (3); however, individually, there was tremendous variation in the results across studies, with some reporting no such association or even a protective relationship (3, 4). Similar inconsistencies have been noted with cigarette smoking, with some studies showing that it is a strong and independent risk factor for severe COVID-19 and others showing the opposite (protective) effect (5). Impaired lung function and presence of emphysema have also been noted to be significant risk factors in some but not all studies (6), creating confusion. https://tinyurl.run/WneBNi