By Antonella Macerollo
For May 2021, we have selected: Rentsch CT et al. Early initiation of prophylactic anticoagulation for prevention of coronavirus disease 2019 mortality in patients admitted to hospital in the United States: cohort study. BMJ 202;372:n311. doi: 10.1136/bmj.n311.
The global spread of the COVID-19 infection has highlighted that deaths among COVID-19 patients are partially attributed to venous thromboembolism and arterial thromboses. In the absence of a specific treatment for this viral infection, it is mandatory to develop symptomatic therapeutic strategies to reduce the consequences of the infection.
It is well known that anticoagulants prevent thrombosis formation and possess antiviral and potentially anti-inflammatory properties. Therefore, it has been thought that they might be particularly effective in patients with COVID-19.
Our paper of the month is an observational cohort study evaluating whether prophylactic anticoagulation within 24 hours of admission, compared with no anticoagulation, reduced the risk of death among 4297 patients. The patients were treated at several hospitals in the USA and recorded at the Department of Veterans Affairs from 1 March to 31 July 2020. All had a laboratory confirmed positive SARS-CoV-2 test result on or within 14 days before admission.
Exclusion criteria were: no history of care (defined as at least one outpatient or inpatient encounter in the two years before 1 March 2020); anticoagulation treatment in the 30 days before hospital admission; a red blood cell transfusion within 24 hours of admission; experiencing any outcome within 24 hours of admission.
Rentsch et al evaluated the 30-day mortality as primary outcome. Secondary outcomes were inpatient mortality, initiation of therapeutic anticoagulation due to clinical deterioration and transfusion due to bleeding.
In this study 84.4% (3627) of patients received prophylactic anticoagulation within 24 hours of admission as subcutaneous heparin or enoxaparin.
622 deaths occurred within 30 days of hospital admission. Of note: 513 in the prophylactic anticoagulation group and 510 during hospital stay.
The cumulative incidence of mortality at 30 days was 14.3% in the prophylactic anticoagulation group and 18.7% in the non-treated group.
The patients treated with anticoagulation had a 27% decreased risk for 30-day mortality. Similar associations were found for inpatient mortality and initiation of therapeutic anticoagulation. These benefits seemed to be greater among patients not admitted to the ICU within 24 hours of hospital admission. Importantly, the anticoagulation group did not show an increased risk of bleeding that required transfusion.
These findings provide strong evidence leading towards guidelines recommending the use of prophylactic anticoagulation as initial treatment for COVID-19 patients on hospital admission.