ABSTRACT
Background : A high incidence of venous thromboembolism (VTE) is observed in patients with COVID-19. Furthermore, several studies show that hypercoagulability is associated with mortality. Aims : To investigate whether pre-admission anticoagulant therapy is associated with a lower risk of all-cause mortality in hospitalized COVID-19 patients. Methods : Retrospective data from 1,851 consecutive patients with PCR-confirmed SARS-CoV-2 infection hospitalized in eight Dutch centres between February 27 th and August 1 st 2020 were used. During this period, Dutch guidelines recommended routine thromboprophylaxis for all hospitalized COVID-19 patients. After 1:1 propensity score nearest-neighbour matching based on age, sex, and 17 comorbidities, the association between pre-admission anticoagulant therapy for VTE, atrial fibrillation, or other indications (i.e. direct oral anticoagulants or vitamin K antagonists) and all-cause mortality and intensive care unit (ICU) admission was evaluated. A secondary analysis was performed with a broader definition of antithrombotic therapy including anticoagulants and antiplatelet drugs. Results : Mean age was 66.4 years (SD, 14.8) and 39% were women. Pre-admission, 678 patients (37%) were using anticoagulant and/or antiplatelet therapy of whom 287 (16%) used anticoagulant therapy only, 408 (22%) antiplatelet therapy only, and 17 both anticoagulant and antiplatelet therapy. 253 anticoagulant users and 253 patients not using therapeutic anticoagulation were matched. During a median follow-up of 21 days [IQR: 9.8-21.0], anticoagulant therapy was neither associated with all-cause mortality (hazard ratio [HR], 0.95;95%-CI, 0.70-1.27;Figure 1) nor with ICU admission (HR, 1.0;95%-CI, 0.59-1.70). Results did not materially change in the secondary analysis of anticoagulant and/or antiplatelet therapy (HR for mortality, 1.18 [95%-CI, 0.87-1.59] and HR for ICU admission, 2.98 [95%-CI, 0.60-1.39]). Conclusions : In this retrospective cohort study, pre-admission anticoagulant use was not associated with a lower risk of mortality or ICU admission in hospitalized COVID-19 patients. Further data from randomized controlled trials are needed to determine the riskbenefit ratio of initiating anticoagulant therapy during admission for COVID-19.