The Epidemiology of Acute Respiratory Distress Syndrome Before and After Coronavirus Disease 2019.

Acute respiratory distress syndrome (ARDS) is a heterogeneous syndrome of high morbidity and mortality with global impact. Current epidemiologic estimates are imprecise given differences in patient populations, risk factors, resources, and practice styles around the world. Despite improvement in supportive care which has improved mortality, effective targeted therapies remain elusive. The Coronavirus Disease 2019 pandemic has resulted in a large number of ARDS cases that, despite less heterogeneity than multietiologic ARDS populations, still exhibit wide variation in physiology and outcomes. Intensive care unit rates of death have varied widely in studies to date because of a variety of patient and hospital-level factors. Despite some controversy, the best management of these patients is likely the same supportive measures shown to be effective in classical ARDS. Further epidemiologic studies are needed to help characterize the epidemiology of ARDS subphenotypes to facilitate identification of targeted therapies.