Taking aspirin may reduce the need for mechanical ventilation, admission to an intensive care unit (ICU) and in-hospital mortality among people hospitalised with Covid-19, according to a study in Anesthesia & Analgesia.

Hypercoagulability and increased thrombotic risk are common among people critically ill with Covid-19 – between 25 and 42 per cent of Covid-19 patients develop thrombotic complications, which may increase mortality.

The retrospective and observational study enrolled 412 people in the US hospitalised with Covid-19. Median age was 55 years. Of these, 59.2 per cent were male and 76.3 per cent did not take aspirin. The remainder received aspirin within 24 hours of admission or during the seven days before admission.

Patients receiving aspirin, compared with controls, had significantly lower rates of mechanical ventilation (35.7 and 48.4 per cent respectively) and ICU admission (38.8 and 51.0 per cent respectively). No statistically significant difference emerged for in-hospital mortality (26.5 and 23.2 per cent respectively). 

After adjusting for potential confounders, aspirin was independently associated with a 47 per cent reduced risk of in-hospital mortality, a 44 per cent reduced risk of mechanical ventilation and a 43 per cent reduced risk of ICU admission.

No statistically significant difference emerged in the rates of major bleeding (6.1 and 7.6 per cent respectively) or overt thrombosis (8.2 and 8.9 per cent) between aspirin users and controls. However, larger studies need to assess aspirin’s bleeding risk in Covid-19 patients. The authors were unable to allow for other medications associated with hypercoagulability, including oral contraceptives and hormone replacement therapy. 

“This is a critical finding that needs to be confirmed through a randomised clinical trial,” said study leader Dr Jonathan Chow, assistant professor of anesthesiology at University of Maryland School of Medicine. “If our finding is confirmed, it would make aspirin the first widely available, over-the-counter medication to reduce mortality in Covid-19 patients.”