Objectives: To determine the impact of anticoagulation on inhospital mortality among coronavirus disease 2019-positive patients with the a priori hypothesis that there would be a lower risk of inhospital mortality with use of preemptive therapeutic over prophylactic dose enoxaparin or heparin. Design Setting: Retrospective cohort study from April 1, 2020, to April 25, 2020. The date of final follow-up was June 12, 2020 Two large, acute-care hospitals in Western Connecticut. Patients: Five hundred and one inpatients were identified after discharge as 18 years or older and positive for severe acute respiratory syndrome coronavirus 2. The final sample size included 374 patients after applying exclusion criteria. Demographic variables were collected via hospital billing inquiries, whereas the clinical variables were abstracted from patients’ medical records. Exposure: Preemptive enoxaparin or heparin at a therapeutic or prophylactic dose. Main Results: When comparing treatments through multivariable analysis, risk of inhospital mortality was 2.3 times greater in patients receiving preemptive therapeutic anticoagulation (95% CI = 1.0–4.9; p = 0.04). Additionally, the average treatment effects were higher (β = 0.11, p = 0.01) in the therapeutic group. Conclusions: An increase in inhospital mortality was observed among patients on preemptive therapeutic anticoagulation. Thus, in the management of coronavirus disease 2019 and its complications, we recommend further research and cautious use of preemptive therapeutic over prophylactic anticoagulation.

Background: This study is the first of its kind to assess the impact of preemptive therapeutic dose anticoagulation on mortality compared to prophylactic anticoagulation among COVID-19 patients. Its findings provide insight to clinicians regarding the management of COVID-19, particularly with the known prothrombotic state. Research Question: To determine the impact of anticoagulation on in-hospital mortality among COVID-19 positive patients with the a priori hypothesis that there would be a lower risk of in-hospital mortality with use of preemptive therapeutic over prophylactic dose enoxaparin or heparin. Study Design and Methods: Study Design: Retrospective cohort study from April 1 - April 25, 2020. The date of final follow-up was June 12, 2020. Setting: Two large, acute care hospitals in Western Connecticut. Participants: Five hundred and one inpatients were identified after discharge as 18 years or older and positive for SARS-CoV-2. The final sample size included 374 patients after applying exclusion criteria. Demographic variables were collected via hospital billing inquiries, while the clinical variables were abstracted from patients medical records. Exposure: Preemptive enoxaparin or heparin at a therapeutic or prophylactic dose. Main Outcome: In-hospital mortality. Results: When comparing preemptive therapeutic to prophylactic anticoagulation through multi-variable analysis, risk of in-hospital mortality was 2.3 times greater in patients receiving preemptive therapeutic anticoagulation (95% CI = 1.0, 4.9; p = 0.04). Interpretation: An increase in in-hospital mortality was observed with preemptive therapeutic anticoagulation. Thus, in the management of COVID-19 and its complications, we recommend further research and cautious use of preemptive therapeutic over prophylactic anticoagulation.