Full-Dose Anticoagulation Linked With Heavy Bleeding in COVID-19 ICU Patients

Giving COVID-19 patients in intensive care full-dose anticoagulation increases their risk of heavy bleeding but doesn’t show much greater effectiveness than a more moderate dose, according to a new study. Find out what the authors recommend for treating blood clots for those critically ill patients, nearly all of whom were mechanically ventilated.

BUFFALO, NY—COVID-19 patients in the intensive care unit shouldn’t get full-dose anticoagulation without an additional indication, a new study advises.

The report in Hospital Pharmacy cautions that those are significantly more likely to experience heavy bleeding than patients prescribed a smaller yet equally effective dose. The research led by University of Buffalo investigators compared the safety and effectiveness of blood clot treatment strategies for more than 150 critically ill COVID-19 patients at multiple hospitals.


The study reports that nearly all ICU patients who experienced significant bleeding were mechanically ventilated and receiving full-dose anticoagulants.

The authors suggest their findings could influence treatment guidelines for blood clots in hospitalized COVID-19 patients, whose infection puts them at greater risk for both blood clots and severe bleeding.

First author Maya Chilbert, PharmD, clinical assistant professor in the UB School of Pharmacy and Pharmaceutical Sciences, points out that, based on previous studies, about 17% of hospitalized COVID-19 patients develop blood clots. “A wide variety of practice exists when it comes to approaching blood clots in hospitalized patients with COVID-19, and there is little data to suggest improved outcomes using one strategy versus another,” says Chilbert. “Caution should be used in mechanically ventilated patients with COVID-19 when selecting a regimen to treat blood clots, and the decision to use full-dose blood thinners should be based on a compelling indication rather than lab markers alone.”

The study looked at two dosing protocols: Regimen A used higher-than-standard thromboprophylaxis dosage and Regimen B received full-dose anticoagulation for any D-dimer 3 mcg/mL or greater and prophylactic for less than 3 mcg/mL. The rate of thrombotic events between treatment groups was defined as the primary outcome, while secondary endpoints compared rates of major or clinically relevant non-major bleeding, as well as the proportion of patients in each group experiencing thrombotic events within 30 days of discharge. 

Of the 153 patients included in the analysis, 64 received Regimen A and 89 received Regimen B. Results indicate that 7 (4.6%) thrombotic events occurred, 3 (4.7%) in patients receiving Regimen A, and 4 (4.5%) in Regimen B (P = 1.0). In addition, 12 patients (13.5%) receiving Regimen B had a bleeding event vs. 2 (3.1%) in Regimen A (P = .04); half of those were major in each group.

The study also verified that all patients who bled in either treatment group were receiving mechanical ventilation, and 12 of 14 were receiving full-dose anticoagulation. One patient receiving Regimen A was readmitted with a pulmonary embolism. 

“In this study, the thromboprophylactic regimen impacted bleeding, but no significant difference was seen with thrombotic outcomes,” the authors conclude.

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