Association between antithrombin and mortality in patients with COVID-19. A possible link with obesity

Background and aims: Despite anticoagulation, usually with heparin, mortality for thromboembolic events in COVID-19 remains high. Clinical efficacy of heparin is due to its interaction with antithrombin (AT) that may be decreased in COVID-19. Therefore, we correlated AT levels with outcomes of COVID-19. Methods and results: We recruited 49 consecutive patients hospitalized for COVID-19. AT levels were significantly lower in 16 non-survivors than in 33 survivors (72.2 +/- 23.4 versus 94.6 +/- 19.5%; p = 0.0010). A multivariate Cox regression analysis showed that low AT (levels below 80%) was a predictor of mortality (HR:3.97; 95%CI:1.38 to 11.43; p = 0.0103). BMI was the only variable that showed a significant difference between patients with low and those with normal AT levels (32.9 +/- 7.9 versus 27.5 +/- 5.9%; p = 0.0104). AT levels were significantly lower in obese patients than in subjects with normal weight or overweight (77.9 +/- 26.9 versus 91.4 +/- 26.9 versus 91.4 +/- 17.1%; p = 0.025). An inverse correlation between AT levels and BMI was documented (r:-0.33; p = 0.0179). Conclusions: Our data first suggest that AT is strongly associated with mortality in COVID-19. In addition, AT may be the link between obesity and a poorer prognosis in patients with COVID-19. Other studies should confirm whether AT may become a prognostic marker and a therapeutic target in COVID-19. (C) 2020 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.