The RECOVERY trial was established as a randomised clinical trial to test a range of potential treatments for patients hospitalised with COVID-19. Patients with COVID-19 are at increased risk of blood clots forming in their blood vessels, particularly in the lungs. Between November 2020 and March 2021, the RECOVERY trial included nearly 15,000 patients across the UK hospitalised with COVID-19 in an assessment of the effects of aspirin, which is widely used to reduce blood clotting in other diseases.

Nationally, a total of 7351 patients were randomised to aspirin 150 mg once daily and compared with 7541 patients randomised to usual care alone. There was no evidence that aspirin treatment reduced mortality. There was no significant difference in the primary endpoint of 28-day mortality (17% aspirin vs. 17% usual care; rate ratio 0.96 [95% confidence interval 0.89-1.04]; p=0.35). The results were consistent in all pre-specified subgroups of patients.

Patients allocated to aspirin 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%; rate ratio 1·06; 95% CI 1·02-1·10; p=0·0062). Among those not on invasive mechanical ventilation at baseline, there was no significant difference in the proportion who progressed to invasive mechanical ventilation or death (21% vs. 22%; risk ratio 0·96; 95% CI 0·90-1·03; p=0·23). 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.

The results of this evaluation of aspirin have been published on medRxiv and have been submitted to a leading peer-reviewed medical journal.

At the Edinburgh site we are continuing to recruit to the ongoing arms of the RECOVERY trial, including baracitininb and dimethyl fumerate. Find out more about the ongoing study here.