Hospital-based use of thromboprophylaxis in patients with COVID-19.

Physicians are receiving a great deal of information regarding how to care for patients with coronavirus disease 2019 (COVID-19). We would like to offer further information about thromboprophylaxis that we believe is worth considering when treating patients who have been admitted to hospital with COVID-19.

Tang and colleagues described a consecutive series of 183 patients who had been admitted to hospital with COVID-19 in China. Activation of the coagulation system was found in many patients, and the degree of activation (defined as, for example, increased D-dimer concentrations at time of admission) was significantly higher in patients who did not survive than those who did survive. Overall, 21 (11%) of 183 patients died. 15 (71%) of 21 non-survivors and only one (1%) of 162 survivors met criteria for disseminated intravascular coagulation during their hospital stay. In a case series from China, increased D-dimer concentration at time of admission to hospital (>1 μg/mL) was associated with a risk of in-hospital mortality that was 18 times higher than among those with normal D-dimer concentrations, and the authors highlighted that “inadequate adherence to standard supportive therapy”, among other things, might have led to poor outcomes in some patients.

Acutely ill patients with severe viral pneumonia and acute respiratory distress syndrome (ARDS), such as those with H1N1 infection, who have been admitted to hospital have a 23-times increased risk for pulmonary embolism, and guidelines support routine thromboprophylaxis in these patients. Increased D-dimer concentrations of more than double the upper limit of normal has emerged as a new biomarker to predict risk of venous thromboembolism in all patients in hospitals. Trial subgroup analyses, in which increased D-dimer concentration or admission to hospital with infection (particularly pneumonia) were incorporated as variables, show that extended thromboprophylaxis with direct oral anticoagulants has benefit compared with routine in-hospital thromboprophylaxis with low molecular weight heparin. Finally, empirical anticoagulation has been associated with improved thrombotic event-free survival in critically ill patients with ARDS due to influenza A H1N1.

In light of this evidence, and the fact that hospitals might soon have a large number of patients with COVID-19 who might meet guideline requirements for thromboprophylaxis, we believe it seems prudent to use thromboprophylaxis in such patients, particularly those with evidence of activation of the coagulation system (eg, increased D-dimer concentrations) on admission.

Of utmost importance will be the prospective, real-time data collection to assess whether use of thromboprophylaxis in patients with COVID-19 leads to improved outcomes, including improved survival, without clinically important bleeding.