Published: 08 June 2021
The NIHR-supported RECOVERY trial has found that the anti-inflammatory drug aspirin - a treatment widely used to reduce blood clotting in other diseases - does not improve survival for patients who are hospitalised with COVID-19.
Patients with COVID-19 are at increased risk of blood clots forming in their blood vessels, particularly in the lungs. It was hoped that aspirin may help reduce blood clotting and therefore improve lung function and patient outcomes in severe cases of COVID-19.
The RECOVERY trial assessed the effects of aspirin in a cohort of nearly 15,000 hospitalised COVID-19 patients. A total of 7,351 patients were randomised to receive 150 mg aspirin once daily, with results compared against 7,541 patients who received standard care alone.
The researchers found no evidence that aspirin treatment reduced mortality in hospitalised patients with COVID-19. There was no significant difference in the primary endpoint of 28-day mortality (17% aspirin vs. 17% usual care). These results were consistent in all pre-specified subgroups of patients.
Patients randomised to the aspirin group had a slightly shorter duration of hospitalisation (median 8 days vs. 9 days) and a higher proportion were discharged from hospital alive within 28 days (75% vs. 74%). There was no significant difference in the proportion of patients who were not receiving invasive mechanical ventilation at baseline, who progressed to invasive mechanical ventilation or death (21% vs. 22%). For every 1000 patients treated with aspirin, approximately 6 more patients experienced a major bleeding event and approximately 6 fewer experienced a thromboembolic (clotting) event.
Dr William van’t Hoff, Chief Executive of the NIHR Clinical Research Network said:
“While it is disappointing that aspirin has not been found to improve mortality for hospitalised COVID-19 patients, the trial has again contributed important evidence about what does and what does not work, data that can be used around the world. We want to sincerely thank the thousands of patients who have taken part and the staff in the NHS and NIHR who have supported this vital study, continuing to advance the science around COVID-19.”
Peter Horby, Professor of Emerging Infectious Diseases in the Nuffield Department of Medicine, University of Oxford, and Joint Chief Investigator for the RECOVERY trial, said:
“The data show that in patients hospitalised with COVID-19, aspirin was not associated with reductions in 28-day mortality or in the risk of progressing to invasive mechanical ventilation or death. Although aspirin was associated with a small increase in the likelihood of being discharged alive this does not seem to be sufficient to justify its widespread use for patients hospitalised with COVID-19.”
Martin Landray, Professor of Medicine and Epidemiology at the Nuffield Department of Population Health, University of Oxford, and Joint Chief Investigator, said:
“There has been a strong suggestion that blood clotting may be responsible for deteriorating lung function and death in patients with severe COVID-19. Aspirin is inexpensive and widely used in other diseases to reduce the risk of blood clots so it is disappointing that it did not have a major impact for these patients. This is why large randomised trials are so important – to establish which treatments work and which do not.”
The results from the aspirin of the RECOVERY trial will be published on medRxiv and have been submitted to a peer-reviewed medical journal.
RECOVERY is jointly funded by NIHR and UKRI, while recruitment of participants is supported by the NIHR Clinical Research Network and devolved administrations across the United Kingdom. The trial was established as a randomised clinical trial to test a range of potential treatments for patients hospitalised with COVID-19.
Since it launched in March 2020, the study has produced evidence to establish some of the world’s first identified life saving treatments for COVID-19 - dexamethasone and tocilizumab.