Risk Factors of Bleedings in Patients with COVID-19 Receiving Anticoagulants for Venous Thromboembolism Prevention

Objective. To analyze the risk factors of hemorrhagic complications of anticoagulant prophylaxis of venous thromboembolism (VTE) in patients with a new coronavirus infection (COVID-19). Material and methods. A prospective observational study included 370 patients with COVID-19. Patients received anticoagulants for the underlying disease. In the 1st group (190 patients), low molecular weight heparin (LMWH) was used, in the 2nd group (123 patients) — unfractionated heparin (UFH). The 3rd group included 57 patients who received direct oral anticoagulants before admission. The incidence of hemorrhagic complications and their predictors were assessed. Results. Major bleeding was common in patients receiving UFH (4.9% of cases). These events included gastrointestinal, bronchial and genitourinary tract. The incidence of clinically significant bleeding was comparable in all groups. These bleedings were represented by nasal, hemorrhoidal, pulmonary bleeding (hemoptysis) and hematomas. Minor bleedings were more common in patients receiving UFH (17.9% of cases). These events included gingival bleeding, subcutaneous hematomas. Among the anticoagulants associated with the development of bleeding, there were parenteral anticoagulants in therapeutic doses. Direct oral anticoagulants did not lead to life-threatening bleeding. Therapeutic dosage of parenteral anticoagulants was the main risk factor of life-threatening bleeding. Anamnestic risk factors included obesity, chronic venous diseases and previous VTE. In addition, serum ferritin, leukocytes, D-dimer and fibrinogen were higher in patients with bleeding. Conclusion. Risk factors of bleeding during anticoagulant prophylaxis of VTE in COVID-19 patients include obesity, chronic venous insufficiency, previous VTE, increased serum ferritin, leukocytes, D-dimer and fibrinogen. Therapeutic doses of LMWH are associated with high incidence of bleeding.