DOAC (direct oral anticoagulant) pills are used in the treatment of atrial fibrillation by preventing blood clots but although blood clots are thought to contribute to complications from the new coronavirus infection, users of this class of drug do not seem to be protected against severe COVID-19, a large Karolinska Institutet registry study, published in The Journal of Internal Medicine, finds.
Early during the ongoing pandemic, there were reports that many patients with severe COVID-19 had blood clots in their pulmonary arteries and other parts of the body.
"Our hypothesis was that blood clots per se could contribute to the severe functional deterioration of the lungs and other organs that is associated with COVID-19, so one would think that preventative treatment with anticoagulants would provide some protection," says Benjamin Flam, doctoral student at the Department of Physiology and Pharmacology, Karolinska Institutet, and specialist doctor in anaesthesiology and intensive care at Karolinska University Hospital.
To find out if this was the case, the team from KI conducted a registry based study of patients on anticoagulant medication for reasons other than COVID-19. The study included over 100,000 Swedes between the ages of 45 and 84 with atrial fibrillation being treated with DOACs. The control groups included over 350,000 individuals with cardiovascular disease who were not on such medication.
The researchers then examined the rates of hospitalisation, intensive care and fatality due to COVID-19 between 1 February and 31 May 2020, adjusting for such factors as age, sex, place of residence and other diseases and medication.
The results of the observational study show that DOAC use did not reduce the rate of hospitalisation, intensive care or fatality due to COVID-19.
"Our findings suggest that early DOAC treatment doesn't protect against severe COVID-19, but these should be treated with caution since there might remain differences between the groups that are difficult to measure," says Benjamin Flam. "Also, our study says nothing about whether other types of anticoagulants could be effective, but a good many clinical studies are being done around the world."
The research was financed by grants from Region Stockholm (ALF funding), the Strategic Research Area in Epidemiology at Karolinska Institutet and the Swedish Research Council. Co-author Jonas F Ludvigsson is leading a study funded by the company Janssen on behalf of the Swedish IBD quality registry (SWIBREG).
ABSTRACT
Background
Hypercoagulability and thromboembolism are prominent features of severe COVID‐19, and ongoing anticoagulant use might be protective.
Methods
We conducted a nationwide register‐based cohort study in Sweden, February through May, 2020, to assess whether ongoing direct oral anticoagulant (DOAC) use was associated with reduced risk of hospital admission for laboratory‐confirmed COVID‐19, or a composite of intensive care unit (ICU) admission or death due to laboratory‐confirmed COVID‐19.
Results
DOAC use (n=103 703) was not associated with reduced risk of hospital admission for COVID‐19 (adjusted hazard ratio [aHR] [95% confidence interval] 1.00 [0.75‐1.33] vs. non‐use atrial fibrillation comparator [n=36 875]; and aHR 0.94 [0.80‐1.10] vs. non‐use cardiovascular disease comparator [n=355 699]), or ICU admission or death due to COVID‐19 (aHRs 0.76 [0.51‐1.12], and 0.90 [0.71‐1.15], respectively).
Conclusion
Ongoing DOAC use was not associated with reduced risk of severe COVID‐19, indicating that prognosis would not be modified by early outpatient DOAC initiation.
Journal Reference
Direct oral anticoagulant use and risk of severe COVID‐19
Benjamin Flam, Viktor Wintzell, Jonas F. Ludvigsson, Johan Mårtensson, Björn Pasternak.
Journal of Internal Medicine, 1 December 2020
[link url="https://onlinelibrary.wiley.com/doi/10.1111/joim.13205"]Full pre-publication text in Journal of Internal Medicine (Open access)[/link]
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