Aspirin Fails to Improve ARDS Outcomes in a Phase 2 Trial

Pavankumar Kamat

November 26, 2021

In a phase 2 randomised controlled trial, aspirin was well tolerated but failed to improve oxygenation index (OI) and physiological outcomes of lung injury or organ dysfunction in patients with acute respiratory distress syndrome (ARDS).

Platelet aggregation is likely to be involved in the pathophysiology of ARDS. Mouse models of ARDS have shown aspirin to decrease neutrophil migration and pulmonary oedema development in the lungs and improve survival. Several observational studies have also shown low dose aspirin to improve outcomes in patients with ARDS. The STAR (ASpirin as a Treatment for ARDS) trial was designed to investigate whether aspirin 75 mg could be an effective treatment option for ARDS.

In the randomised, double blind, placebo-controlled, phase 2 STAR trial conducted across 5 intensive care units in the UK, patients who met the Berlin criteria for ARDS were randomly assigned (1:1) to receive either enteral aspirin 75 mg or placebo for a maximum duration of 14 days. Of the planned 60 patients, only 49 (aspirin: 24; placebo: 25) were recruited after early termination of the trial due to slow recruitment. The primary outcome was oxygenation index (OI) at day 7.

The findings published in the journal  Chest  showed no significant difference in OI at day 7 between the aspirin and placebo groups (mean difference, 12.0; P=0.19). Similarly, there were no significant differences between groups in the secondary outcomes of OI at days 4 and 14, respiratory compliance and PaO2/FIO2 ratio on days 4, 7 and 14, and Sequential Organ Failure Assessment (SOFA) score change from baseline to days 4, 7 and 14. Additionally, there was no significant difference in 28 or 90- day mortality rates between the groups.

A total of 26 adverse events (AEs) were reported (13 in each group; OR, 1.04; P=0.56), including 5 serious AEs (2 in the aspirin group and 3 in the placebo group). The most common AE was reduction in haemoglobin levels (7 events in the aspirin group and 8 in the placebo group).

"These data do not support the use of low dose aspirin in the treatment of ARDS, furthermore the feasibility of a large interventional study of aspirin in ARDS is questionable, unless further studies are less restrictive in their exclusion criteria," the authors concluded.

The research was funded by the Health & Social Care Research & Development Division of the Public Health Agency, Northern Ireland.


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