Anticoagulation Among Patients Hospitalized With COVID-19

Quick Takes

  • Patients hospitalized with COVID-19 are at risk for venous thromboembolism.
  • In a large single system analysis, anticoagulation use was associated with lower rates of death and intubation.
  • It is unclear if prophylactic or treatment doses of anticoagulation are needed to prevent thrombosis in hospitalized patients with COVID-19.

Study Questions:

What is the association of anticoagulation use with in-hospital outcomes and thromboembolic events in patients hospitalized with coronavirus disease 2019 (COVID-19)?


The authors analyzed data from 4,389 patients hospitalized in a five-center New York City health system between April 1 and May 30, 2020. Patients who were admitted for <24 hours and those receiving both prophylactic and therapeutic anticoagulation were excluded from analysis. They explored the association between levels of anticoagulation use (non, prophylactic, therapeutic) with in-hospital mortality, intubation, and major bleeding. The investigators used propensity-score weighting, landmark analyses, and sensitivity analyses to minimize the effect of bias and confounding. One key subgroup analysis was limited to patients receiving anticoagulation within 48 hours of admission.


Among the 4,389 patients hospitalized with COVID-19 (median age 65 years, 44% female), no anticoagulation was used in 1,530 (34.9%) patients, prophylactic anticoagulation was used in 1,959 (44.6%) patients, and therapeutic anticoagulation was used in 900 (20.5%) patients. As compared to patients receiving no anticoagulation, those who received prophylactic or therapeutic anticoagulation had a lower risk of in-hospital mortality (adjusted hazard ratio [aHR], 0.50; 95% confidence interval [CI], 0.45-0.57 and aHR, 0.53; 95% CI, 0.45-0.62, respectively). Both levels of anticoagulation were also associated with a lower risk of intubation as compared to no anticoagulation (aHR, 0.72; 95% CI, 0.58-0.89 for prophylactic and aHR, 0.69; 95% CI, 0.51-0.94 for therapeutic anticoagulation). In the subgroup analysis limited to treatment within 48 hours of admission, there was no statistically significant difference in in-hospital mortality or intubation risk between therapeutic and prophylactic dose anticoagulation (aHR, 0.86; 95% CI, 0.73-1.02 and aHR, 0.94; 95% CI, 0.74-1.21, respectively). Rates of major bleeding were highest among patients on therapeutic anticoagulation (3.0%) and similar for patients on prophylactic (1.7%) or no anticoagulation (1.9%).


The authors concluded that anticoagulation was associated with lower mortality and risk of intubation among patients hospitalized with COVID-19 without a statistically significant difference between levels of anticoagulation therapy administered.


This manuscript provides a more comprehensive summary of mortality and intubation risk associated with COVID-19 hospitalization than the investigators’ initial interim report (Paranjpe I, et al., J Am Coll Cardiol 2020;76:122-4). These data support the notion that anticoagulation should be given, largely for the purpose of venous thromboembolism prophylaxis. However, they do not provide clear evidence that higher-intensity treatment is beneficial. Ongoing randomized clinical trials are critically important for assessing the potential risks and benefits associated with different levels of anticoagulation intensity. This study does provide reassurance that rates of major bleeding were not markedly elevated, even among patients receiving therapeutic anticoagulation. Pending the results of ongoing randomized clinical trials, most guidelines and guidance documents favor the use of standard prophylactic anticoagulation for most hospitalized patients with COVID-19. Use of intermediate or therapeutic doses of anticoagulation for the purpose of thromboembolism prophylaxis should be done selectively and (preferably) in the setting of a clinical trial or prospective registry whenever possible.

Clinical Topics: Anticoagulation Management, Prevention

Keywords: Anticoagulants, Coronavirus, COVID-19, Hemorrhage, Hospital Mortality, Intubation, Primary Prevention, severe acute respiratory syndrome coronavirus 2, Thromboembolism, Vascular Diseases

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