Incidence of Venous Thromboembolism in Hospitalized COVID-19 Patients Receiving Thromboprophylaxis.

The purpose of this study was to investigate the association between anticoagulant dosing intensity in coronavirus disease 2019 (COVID-19) infected patients and its outcomes on venous thromboembolism (VTE) and all-cause mortality. This is a retrospective observational study that examined different anticoagulation regimens among COVID-19 patients for prophylaxis of VTE. Primary outcomes of the study were VTE incidence and all-cause mortality for patients receiving prophylaxis-intensity (PPX) and therapeutic-intensity (TX) anticoagulation. Secondary outcomes were incidence of hemorrhagic events and hospital length of stay. Patients were matched (1:1) based on age and Charlson comorbidity score. Sub-group analyses evaluated outcomes within critically ill patients, between specific anticoagulant agents and comorbid conditions. The primary outcome of VTE occurred in six patients within the prophylactic dose group and eight patients in the therapeutic-intensity dose group (risk ratio (RR): 2.02 (95% confidence interval (CI): 0.7 - 5.2); P = 0.2). Bleeding occurred in 15 (11%) patients in the prophylactic group and 27 (19%) patients in the therapeutic group (RR: 0.5 (95% CI: 0.3 - 1.0); P < 0.049). Hospital length of stay was shorter by 4 days in those treated with prophylactic-intensity anticoagulation (P = 0.003). Intensive care unit admission and ventilation were negatively correlated with mortality in a multivariate analysis. Among hospitalized COVID-19 patients, the use of therapeutic-intensity anticoagulation did not show any benefits in reducing the occurrence of VTE. An increase in mortality and in the incidence of hemorrhagic events was statistically significant in the therapeutic-intensity group. Future prospective studies are warranted to evaluate anticoagulation therapy in COVID-19 infected patients.