Impact of pre-admission antithrombotic therapy on disease severity and mortality in patients hospitalized for COVID-19.

Anticoagulant therapy is a cornerstone treatment for coronavirus disease 2019 (COVID-19) due to the high rates of thromboembolic complications associated with this disease. We hypothesized that chronic antithrombotic therapy could play a protective role in patients hospitalized for COVID-19. Retrospective, observational study of all patients admitted to our hospital for ≥ 24 h from March 1 to May 31, 2020 with SARS-CoV-2. The objective was to evaluate clinical outcomes and mortality in COVID-19 patients receiving chronic anticoagulation (AC) or antiplatelet therapy (AP) prior to hospital admission. A total of 1612 patients were evaluated. The mean (standard deviation; SD) age was 66.5 (17.1) years. Patients were divided into three groups according to the use of antithrombotic therapy prior to admission (AP, AC, or no-antithrombotic treatment). At admission, 9.6% of the patients were taking anticoagulants and 19.1% antiplatelet therapy. The overall mortality rate was 19.3%. On the multivariate analysis there were no significant differences in mortality between the antithrombotic groups (AC or AP) and the no-antithrombotic group (control group). Patients on AC had lower ICU admission rates than the control group (OR: 0.41, 95% CI, 0.18-0.93). Anticoagulation therapy prior to hospitalization for COVID-19 was associated with lower ICU admission rates. However, there were no significant differences in mortality between the patients receiving chronic antithrombotic therapy and patients not taking antithrombotic medications. These findings suggest that chronic anticoagulation therapy at the time of COVID-19 infection may reduce disease severity and thus the need for ICU admission.