(CVP004) INCIDENCE OF BLEEDING IN NON-CRITICALLY ILL PATIENTS WITH COVID-19 RECEIVING PROPHYLACTIC VERSUS THERAPEUTIC ANTICOAGULATION: A RETROSPECTIVE STUDY

Background: In severe COVID-19 infection, there is fulminant activation of coagulation and consumption of clotting factors leading to micro- and macro-thrombotic complications. Several studies evaluated therapeutic dose anticoagulation in patients hospitalized with COVID-19 infection and demonstrated improved survival compared to prophylactic dose anticoagulation. International clinical guidelines recommend therapeutic dose anticoagulation for hospitalized non-critically ill patients with COVID-19. We aimed to determine the occurrence of major bleeding and clinically relevant non major (CRNM) bleeding or minor bleeding among hospitalized and moderately ill patients with COVID-19 treated with therapeutic dose anticoagulation.

METHODS AND RESULTS: We conducted a retrospective study using medical records of the Jewish General Hospital (JGH), a tertiary care McGill University teaching hospital in Montreal, Canada. All consecutive patients admitted from the emergency department to the COVID clinical units of the JGH between April 1st, 2021, and December 31st, 2021 were enrolled. The JGH adopted therapeutic dose anticoagulation for moderately ill patients with COVID-19 who did not have a relative or absolute contraindication (e.g., advanced renal failure, severe thrombocytopenia (platelets less than 50 (add the units) and need for dual antiplatelet therapy). The inclusion criteria included admission to a non-intensive care COVID unit, serologic diagnosis of COVID-19 and need for supplemental oxygen therapy. Cohort entry date was date of hospital admission, and exit was date of discharge from hospital, transfer to intensive care unit (ICU), or death. The outcome was major bleeding according to the International Society on Thrombosis and Haemostasis (ISTH) criteria. We also determined CRNM bleeding and minor bleeding. Secondary outcomes included objectively confirmed deep venous thrombosis of the lower or upper limbs, pulmonary embolism, splanchnic vein thrombosis, cerebral venous thrombosis as well as arterial thrombotic events, including myocardial, stroke, mesenteric ischemia and limb ischemia. In all, 118 patients were included with a median age of fifty-seven (SD 28), and 60% were men. Thirteen (11%) had pre-existing lung disease. Regarding primary outcome, three (2.5%) patients had major bleeding, none had CRNM bleeding, and one (0.85%) patient had minor bleeding. As a secondary outcome, three (2.5%) patients had a venous thrombotic event, and two (1.7%) patients experienced a cardiovascular arterial event.

Conclusion: Among non-critically ill patients hospitalized with COVID-19 and treated with therapeutic dose anticoagulation, only 2.5% developed a major bleed which is comparable to the reported rates of bleeding in COVID-19 anticoagulation clinical trials. This confirms safety of therapeutic anticoagulation in a non-clinical trial setting for moderately ill patients hospitalized with COVID-19 infection.

Lay Abstract Content: The purpose of our research is to determine the occurrence of bleeding among hospitalized, non-critically ill patients with COVID-19 treated with blood thinners at therapeutic doses. We conducted a retrospective study using medical records of the Jewish General Hospital (JGH), a tertiary care McGill University teaching hospital in Montreal, Canada. We enrolled patients admitted with COVID-19 between April 1st, 2021, and December 31st, 2021. We examined the incidence of bleeding as a primary outcome, and secondarily, that of blood clots. Among 118 patients included in our study, only 2.5% developed a major bleed, which is comparable to the previously reported rates of bleeding in other COVID-19 anticoagulation trials. We therefore confirm the safety of using blood thinners in hospitalized COVID-19 patients not requiring admission to the Intensive Care Unit.