Blood clots, through venous thromboembolism and arterial thromboses, have been shown to be one of the causes of death in individuals with COVID-19. Medications that prevent blood clots, or anticoagulants, may be effective in treating patients with the disease. New research published in The BMJ shows that patients put on preventative doses of anticoagulants within the first 24 hours of being hospitalized with COVID-19 are about 30 percent less likely to die compared to those not put on anticoagulant medication.
Led by researchers at London School of Hygiene & Tropical Medicine (LSHTM), Yale School of Medicine (YSM), Vanderbilt University Medical Center, and the U.S. Department of Veterans Affairs (VA), the observational cohort study found that early initiation of prophylactic anticoagulation was safe and effective in treating patients hospitalized with COVID-19.
"As we await full reporting of ongoing clinical trials, these findings provide strong real-world evidence to support guidelines recommending the use of prophylactic anticoagulation as initial therapy upon hospital admission for COVID-19 patients who do not have a contraindication to this therapy," said LSHTM’s Christopher Rentsch, PhD, study co-lead author.
“This study is an outstanding example of the use of electronic health record data from the national Veterans Affairs Healthcare System to rapidly address urgent problems in health care,” said YSM’s Amy C. Justice, MD, PhD, C.N.H. Long Professor of Medicine (General Medicine) and professor of Public Health (Health Policy) served as co-principal investigator of the study.
Using VA hospitalization data from March 1, 2020 through July 31, 2020, the team looked at each individual with a confirmed COVID-19 diagnosis who was able to receive an anticoagulation medicine within 24 hours of admission to the hospital. Of the 4,297 patients were hospitalized with COVID-19 during this time period, 84 percent received prophylactic anticoagulation within the first 24 hours of admission. Nearly all the patients received subcutaneous heparin or enoxaparin.
The researchers followed these patients to identify who died or experienced a serious bleeding event within 30 days after hospital admission and looked to see if there were differences in the rates of death or serious bleeding events between patients who were given prophylactic doses of anticoagulation and those who received no anticoagulation in the first 24 hours of hospital admission.
14.3 percent of patients who received prophylactic anticoagulation and 18.7 percent of patients who didn’t receive the medication died within thirty days of hospital admission. This amounts to an absolute risk decrease of 4.4 percent or relative risk decrease of 27 percent. Receipt of prophylactic anticoagulation was not associated with increased risk of serious bleeding events. Additionally, researchers concluded that the benefit associated with prophylactic anticoagulation appeared to be greater among patients who were not admitted to the intensive care unit.
This was a large, well-designed study using electronic health record data and comprehensively accounted for reasons why people are given, or not given, anticoagulation. Results were also unchanged in several sensitivity analyses, suggesting that they withstand scrutiny. However, the researchers acknowledge that due to the observational nature of the study, a degree of uncertainty persists that can only be addressed through randomized trials.
Other YSM collaborators included Farah Kidwai-Khan, MS; Janet P. Tate, MPH, ScD; and Joseph T. King, Jr., MD, MSCE. The study was funded by U.S. VA Health Services Research and Development and the National Institutes of Health.