Extended outpatient thromboprophylaxis for individuals with COVID-19

Background : Coronavirus disease 19 (COVID-19) is associated with an increased risk of venous thromboembolism (VTE). Aims : To assess the effectiveness of outpatient thromboprophylaxis in patients with COVID-19. Methods : Consecutive patients hospitalized for SARS from March to May, 2020 were selected. Descriptive statistics, chi-square and t -tests were used to compare COVID-19 and non-COVID-19 patients. Results : The Newcastle upon Tyne Hospital NHS Foundation Trust is a large UK-based teaching hospital. All individuals admitted with COVID-19 were offered outpatient thromboprophylaxis (rivaroxaban 10 mg daily for 28 days) on discharge. Electronic medical records were reviewed for all admissions between 1st April and 15th May 2020, and for up to six months following discharge. Thromboprophylaxis was offered to those not at increased bleeding risk (see Figure 1). The study compares two groups, those individuals who received outpatient thromboprophylaxis (thromboprophylaxis) and those who did not (no thromboprophylaxis). Statistical analysis was performed using Fisher's exact test for categorical data and unpaired t test for continuous data. Data were collected from 179 medical inpatients with COVID-19, of these, 98 were eligible for thromboprophylaxis (Figure 1). The thromboprophylaxis group included 57 (58%) individuals and the no thromboprophylaxis 41 (42%). All medical records were reviewed at 3 and 6 months but all VTE and bleeding events occurred within the 3 months following discharge (see Figure 2). At 3-month follow up there was no difference in the rate of VTE events between the groups (thromboprophylaxis, 1;no thromboprophylaxis, 1;P = 1.00). All VTE events occurred between stopping thromboprophylaxis (at 28 days) and before the 3-month point. The use of thromboprophylaxis was not associated with an increased risk of major bleeding (thromboprophylaxis, 1;no thromboprophylaxis, 0;P = 1.00). The single bleeding event in the thromboprophylaxis group was an intracranial bleed following trauma and occurred two months after stopping the thromboprophylaxis. Conclusions : Extended thromboprophylaxis was not associated with an increased risk of major bleeding. No VTE events occurred whilst an individual was taking thromboprophylaxis. Further work is needed to investigate the optimum duration of thromboprophylaxis.