LettersJune 2021Obesity and Mortality Among Patients Diagnosed With COVID-19FREEAnastasios Kollias, MD, PhD, Konstantinos G. Kyriakoulis, MD, Konstantinos Syrigos, MD, PhDAnastasios Kollias, MD, PhDNational and Kapodistrian University of Athens and Sotiria Hospital, Athens, GreeceSearch for more papers by this author, Konstantinos G. Kyriakoulis, MDNational and Kapodistrian University of Athens and Sotiria Hospital, Athens, GreeceSearch for more papers by this author, Konstantinos Syrigos, MD, PhDNational and Kapodistrian University of Athens and Sotiria Hospital, Athens, GreeceSearch for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/L21-0063 SectionsAboutVisual AbstractPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail TO THE EDITOR: We read with interest Tartof and colleagues' study (1) showing that body mass index (BMI) independently predicted mortality in 6916 patients with COVID-19. High BMI was also shown to be more strongly associated with COVID-19 mortality in younger adults and men.Emerging evidence suggests that SARS-CoV-2 may induce an excessive immune response leading to cytokine storm and coagulation disorders (2). Thus, severe COVID-19 is associated with an increased risk for venous thromboembolic events (VTEs) (2). The latter risk seems to be determined by 3 factors: patient characteristics, including well-established risk factors for VTE; quarantine-associated inactivity, hospitalization conditions, and antithrombotic interventions; and SARS-CoV-2–specific factors (2). In terms of patient characteristics, BMI represents a well-established risk factor for VTE. A recent systematic review and dose–response meta-analysis of cohort studies among 4 million participants showed a significant linear relationship between BMI and risk for VTE (3). The increased risk for VTE among patients with COVID-19 and the preliminary evidence suggesting a survival benefit with the use of antithrombotic treatment have been recognized by international societies that strongly recommend the use of thromboprophylaxis in all hospitalized patients (4).It would be interesting if studies reporting on mortality in patients with COVID-19 made available BMI-related data on VTE incidence and the thromboprophylaxis protocols used. Obesity is known to be associated with an increased risk for a proinflammatory and prothrombotic state, which can also be aggravated by SARS-CoV-2 (1). It could be argued that obese patients have a higher risk for VTE that in turn could partly account for their higher incidence of adverse outcomes in COVID-19. Furthermore, recent autopsy studies have recognized a high incidence of deep venous thrombosis in patients with COVID-19, with pulmonary embolism being identified as a direct cause of death (5). Physicians dealing with patients with COVID-19 should be aware of the high risk for VTE and the need for thromboprophylaxis, especially when obesity is present.