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

Gazzaruso, Carmine; Paolozzi, Enrico; Valenti, Cinzia; Brocchetta, Mauro; Naldani, Daniela; Grignani, Claudio; Salvucci, Fabrizio; Marino, Francesco; Coppola, Adriana; Gallotti, Pietro

Abstract 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.