Understanding the Association Between COVID-19, Thromboembolism, and Therapeutic Anticoagulation

Depiction of a blood clot forming inside a blood vessel. 3D illustration
In expanded research, investigators studied the effects of therapeutic and prophylactic anticoagulation treatment in hospitalized patients with COVID-19.

Among hospitalized patients with coronavirus disease 2019 (COVID-19), those who receive anticoagulation treatment have lower adjusted risk of mortality and intubation compared with in-hospital patients who do not receive anticoagulation, according to study results published in the Journal of the American College of Cardiology.

A team of investigators at Icahn School of Medicine at Mount Sinai in New York, New York, expanded on previous findings that suggested an association between in-hospital anticoagulation and reduced mortality. In the present investigation, the researchers compared the effects of therapeutic and prophylactic anticoagulation treatment with the absence of such treatment. Choice of agent, survival outcomes, intubation, and major bleeding were also analyzed. In addition, the study authors also reviewed the first consecutive autopsies performed at their institution to characterize the premortem management of this patient population as it relates to anticoagulation therapy.

The primary outcome was in-hospital mortality, and secondary outcomes included intubation and major bleeding. Participants were all older than 18 years, had clinically confirmed severe acute respiratory syndrome coronavirus 2 infection between March 1, 2020, and April 30, 2020, and were admitted to 1 of 5 New York City hospitals included in the study.

Of the 4389 eligible patients (median age, 65 years; 44% women), 26% self-identified as African-American and 27% self-identified as Hispanic/Latino; 900 patients were treated with therapeutic anticoagulants, 1959 patients were treated with prophylactic anticoagulants, and 1530 patients were not treated with either. Some patients were treated with anticoagulant (1.8%) or antiplatelet (8.5%) medication prior to admission.

On hospital presentation, patients treated with therapeutic anticoagulants had higher blood pressures, faster heart and respiratory rates, lower oxygen saturation, and higher D-dimer concentrations.

During the study period, 1073 patients died, 2892 were discharged alive, and 424 were still hospitalized. Of the participants who were not treated with any anticoagulation treatment, 60.8% were discharged alive, 25.6% died in hospital, and 13.5% were still hospitalized. Of the participants in the prophylactic anticoagulation group, 75.1% were discharged, 21.6% died in hospital, and 3.2% were still hospitalized. Lastly, 54.3%, 28.6%, and 17.1% of patients in the therapeutic anticoagulation group were discharged, died, or were still hospitalized, respectively.

Compared with no anticoagulation, patients treated with therapeutic or prophylactic anticoagulants had lower rates of in-hospital mortality (adjusted hazard ratios [aHRs], 0.53 and 0.50, respectively). Intubation rates were also favorable for both therapeutic [aHR, 0.69] and prophylactic [aHR, 0.72] anticoagulation groups compared with no anticoagulation treatment.

Major bleeding occurred in 2% of the entire cohort with 27 patients in the therapeutic group, 33 patients in the prophylactic group, and 29 patients in the group that received neither treatment.

Of the 26 autopsies, 11 patients had thromboembolic disease (4 had pulmonary emboli); 4 were on anticoagulants due to atrial fibrillation (3 patients) or previous deep vein thrombosis (1 patient). Of the remaining 22 autopsies, 14 patients were administered anticoagulants upon hospital admission, and 4 received treatment later in their hospital course. Almost none (25 patients) of the 26 autopsies had premortem suspicion of thromboemboli.

“Thromboembolic disease has emerged as an important complication among hospitalized patients with COVID-19,” the researchers wrote.

“The results of randomized controlled trials evaluating different [anticoagulation] regimens for treatment for hospitalized patients with COVID-19 are needed,” the authors concluded.

Disclosure: Some of the authors disclosed financial relationships with pharmaceutical companies and medical device manufacturers. For a full list of disclosures, please refer to the original study.


Nadkarni GN, Lala A, Bagiella E, et al. Anticoagulation, mortality, bleeding and pathology among patients hospitalized with COVID-19: a single health system study. J Am Coll Cardiol. Published online August 26, 2020. doi:10.1016/j.jacc.2020.08.041

This article originally appeared on Hematology Advisor