Do Admitted COVID-19-Positive Patients on Anticoagulation Therapy Have a Reduced Hospital Stay and Disease Severity?


East Florida


Westside Regional Medical Center

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packed red blood cell transfusion, duration of hospital stay, anti-coagulation, coagulation abnormalities, covid 19


Hemic and Lymphatic Diseases | Internal Medicine | Virus Diseases



As of December 2021, the coronavirus disease 2019 (COVID-19) pandemic has resulted in the deaths of over 5 million people. It is known that infection with this virus causes a state of hypercoagulability. Because of this, there has been considerable debate on whether or not patients should be placed on anticoagulation prophylaxis/therapy. The goal of our project was to shed light on this topic by examining the effects of preexisting anticoagulation therapy in COVID-19 patients on disease severity (measured by blood clot readmissions, transfusion counts, and length of hospital stay). In this retrospective cohort study, we conducted an analysis based on data from 30,076 COVID-19-positive patients’ electronic medical records.

Materials and methods

This is a retrospective cohort study. Patients included in this study were identified from the HCA Healthcare corporate database. Registry data was sourced from HCA East Florida hospitals. All patients included in this study were COVID-19 positive via polymerase chain reaction (PCR) or rapid antigen testing on admission and over age 18. A total of 30,076 patients were included in this study with hospital admission dates from March 1, 2020 to June 30, 2021. The analysis examined the relationship between age, sex, blood clot history, and most importantly current anticoagulation status on COVID-19 disease severity (through blood clot readmissions, length of stay, and transfusion count). Blood clot readmissions were analyzed with a logistic regression model while the length of hospital stay and transfusion count were analyzed with a linear regression model.


Our analysis revealed that the odds of experiencing a blood clot readmission is 2.017 times more likely in patients already on anticoagulation therapy compared to those who were not (p = 0.0024). We also found that patients on anticoagulation therapy had a hospital stay of 6.90 days longer on average than patients not on anticoagulation therapy (p < 0.0001). Finally, patients on anticoagulation therapy had, on average, 0.20 more blood transfusions than patients not on anticoagulation therapy (p < 0.001).


While these findings may be affected by the underlying conditions of those on preexisting anticoagulation therapy, they provide valuable insight into the debate on whether COVID-19-positive patients should be anticoagulated on admission to a hospital.

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