Some of the deaths associated with COVID-19 has been attributed to thromboembolic events, thus early introduction of an anticoagulant could offer mortality benefits.
Early in the COVID-19 pandemic, reports from China indicated that a proportion of patients with pneumonia-associated COVID-19 experienced coagulopathy and viral infections are known to create a hypercoagulatory state. Some data from Spain have revealed how the use of heparin was associated with a significant reduction in mortality among those with COVID-19 although a more definitive answer will provided from many of the on-going clinical trials. Nevertheless, results from a large observational study by a collaborative team from the UK and various centres in the US, has provided some important findings of the value of anticoagulation in those infected with COVID-19. Using electronic health records, the team performed a nationwide study in US hospitals of patients admitted to hospital between March and the end of July 2020 who had a PCR-positive COVID-19 test result. The researchers included only those patients admitted to hospital without prior use of any anticoagulants and for whom prophylactic treatment was initiated within 24 hours of admission. They used mortality within 30 days of admission as the primary outcome of interest and included both in-hospital and post-discharge deaths and in the subsequent analysis, adjusted for a number of different potential confounders.
A total of 4297 patients were included in the study with a mean age of 68 years of whom the majority (93.4%) were men. Within this cohort, most patients (84.4%) received prophylactic anticoagulation within 24 hours of their hospital admission which was either subcutaneous heparin (30.2%) or enoxaparin (69.1%). Overall, there were a total of 622 deaths (14.5%) within 30 days of admission. Among those receiving anticoagulation, there was a 27% reduced risk of 30-day mortality (hazard ratio, HR = 0.73, 95% CI 0.66 – 0.81), translating into an absolute risk reduction of 4.4%, though this benefit was greatest among those not admitted to an intensive care unit (HR = 0.91 vs HR = 0.68, admitted vs not admitted). Interestingly, there was no increased risk of bleeding events requiring transfusion (HR = 0.87, 95% CI 0.71 – 1.05).
The authors concluded that their results provide important real-world evidence to recommend the use of prophylactic anticoagulation in those hospitalised with COVID-19.
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 2021; 372: n311.