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oregon; portland; 2019-nCoV


Pharmacy and Pharmaceutical Sciences



In March of 2020, the World Health Organization (WHO) declared the spread of COVID-19 a global pandemic. •Though largely considered a respiratory disease, research continues to demonstrate additional impacts of COVID-19 on other organ systems.2, 3 •A key characteristic of COVID-19 is marked inflammation leading to hypercoagulability.2, 3, 6 •Infected patients are at a higher risk of developing thromboembolic events (VTE and stroke) compared to healthy adults. 2, 3, 6 •Some clinicians have trialed varying anticoagulation strategies for patients with COVID-19 based on coagulation parameters such as D-dimer.4, 5, 6 •Multiple expert groups have released preliminary guidance on anticoagulation strategies for patients with COVID-19; however, there is a lack of consensus.1, 4, 5, 6, 7 •Early reports suggested high rates of VTE in patients infected with COVID-19, despite standard prophylactic doses of anticoagulants.3, 5

Purpose Information from this study is intended to give insight into which anticoagulation strategy is optimal for patients diagnosed with COVID-19.


• Standard dosing –administration of anticoagulant drugs for the primary prevention of VTE •Intermediate dosing –off-label anticoagulant dose greater than standard dosing but lesser than treatment dosing, intended for primary prevention of VTE •Treatment dosing –anticoagulation dosing strategy for the treatment of VTE(s) already present •Bleeding A –overt bleeding requiring medical intervention and interruption/delayed dosing of anticoagulation •Bleeding B –bleeding possibly requiring medical intervention but not requiring interruption or temporary interruption/delayed dosing of anticoagulation


• Study design •Retrospective review of medical records •Data represented here is a homogenous sample (~50%) of a total of 473 patient records to be analyzed •Inclusion criteria •Adults aged 18 years or older and active diagnosis of COVID-19, hospitalized in one of two institutional hospitals in Portland, OR between March 1, 2020 -October 1, 2020, and receiving anticoagulation •Exclusion criteria •Heparin-induced thrombocytopenia in last 100 days, stroke within 30 days, history of hemorrhagic stroke, gastrointestinal bleed in last 60 days, platelet count < 25,000 platelets/microliter, active bleeding upon admission, patients on dual-antiplatelet therapy, patients with brain/spinal/ophthalmologic surgery in last 30 days •Primary outcome •Evaluate inpatient prophylactic anticoagulation strategies and assess outcomes regarding efficacy in the prevention of thromboembolic events •Secondary outcomes •Evaluate safety (presence of bleeding possibly requiring medical intervention) of varying dosing strategies and choice of prophylactic anticoagulation


Patient Population •Total of 229patients included in analysis •Average age 62 years, range 18-96 •Exclusion data (18 patients) •Hx of hemorrhagic stroke, COVID-19 resolved before administration of anticoagulant, presenting with a bleed, on dual-antiplatelet therapy Currently Available Data: •Significant difference (X2= 4.009, p = 0.0452) between incidence of thromboembolism in standard enoxaparin vs intermediate enoxaparin, with greater incidence in intermediate group •Currently no meaningful trends/differences among anticoagulants with limited samples (dabigatran, fondaparinux, rivaroxaban, warfarin). •Among dosing strategies with outcomes of interest, there appears to be no evidence of increased risk of VTE with prophylaxis enoxaparin compared to other dosing strategies (though sample sizes for these are small). •Among dosing strategies with outcomes of interest, there appears to be evidence of increased risk of bleeding with agents other than prophylaxis enoxaparin (apixaban, intermediate enoxaparin, treatment enoxaparin) Limitations •This is a snapshot of patients in the beginning of the pandemic when clinical guidance on optimal anticoagulation strategies was limited and evolving. •Overall practice and treatment of patients diagnosed with COVID-19 has evolved over time and may present confounding factors in assessing outcomes. •This data is limited in capturing overall incidence of VTE as it is limited to inpatient data. Incidence of VTE after hospitalization is not represented in this data and may exhibit differences based on anticoagulation strategy. •Data collected included patients in all areas of the hospital; meaningful difference in acuity of COVID-19 and effect on VTE/bleeding may be underrepresented in this format.

Going Forward

• This data is in line with the 2021 ASH recommendation for standard enoxaparin over intermediate/therapeutic intensity anticoagulation in COVID-19 patients without DVT/PE1 •Further analysis into biomarkers, particularly D-dimer, may be insightful for patients receiving intermediate dosing enoxaparin. •Analysis of demographic trends in patients with outcomes of interest may provide valuable insight. •Statistical analysis pending larger sample is in progress. •Additional research into current COVID-19 patients to account for changes in clinical practice and new strains of the virus is warranted.


Graduate Medical Education



Conference / Event Name

Academic Achievement Day, 2021


Providence Portland Medical Center

Review of Prophylactic Anticoagulation Strategies and Outcomes for COVID-19 Patients (Research in Progress)