Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

1. There was no significant difference in all-cause mortality and need for invasive mechanical ventilation among patients assigned to aspirin versus usual care group.

2. Although aspirin was associated with a reduction in rate of thrombotic events, there were also increases in major bleeding.

Evidence Rating Level: 1 (Excellent)

Study Rundown:

Patients hospitalized with COVID-19 often encounter thromboembolic events during their stay. Although current guidelines suggest use of low molecular weight heparin (LMWH), more affordable and accessible drugs should be explored. Aspirin, a cyclooxygenase-1 enzyme (COX-1) inhibitor, is known to reduce both arterial and venous thrombotic events although its use in patients with COVID-19 lacks evidence. This randomized control trial aimed to assess the safety and efficacy of aspirin among patients admitted with COVID-19. Individuals were assigned to either standard of care plus aspirin (intervention group) or standard of care alone (control group). The primary outcome was mortality at 28 days, while key secondary outcomes included length of hospital stay and need for mechanical ventilation. According to study results, all-cause mortality was similar in both groups, although individuals in the intervention group experienced a shorter hospital stay. A notable limitation of this study was that patients already using aspirin, likely due to increased cardiovascular risk factors, were excluded from study enrollment. Nonetheless, this randomized controlled trial provides crucial information regarding the efficacy of aspirin for a large sample of patients with COVID-19.

Relevant Reading: Comparative Effectiveness of Aspirin Dosing in Cardiovascular Disease

In-depth [randomized controlled trial]:

Between Nov 1, 2020, and Mar 21, 2021, 22 560 patients were assessed for eligibility across 177 hospitals in the UK, Indonesia, and Nepal. Included were those ≥18 years with suspected or confirmed COVID-19, and no contraindications to aspirin or otherwise. Altogether, 14 892 patients were included (7351 to aspirin and 7541 to usual care group) in the final analysis. The primary outcome of all-cause mortality was unchanged with an equal proportion (17%) of patients dying in each group (1222 of 7351 with aspirin vs. 1299 of 7541 with usual care, rate ratio [RR] 0.96, 95% confidence interval [CI] 0.89-1.04, p=0.35). Likewise, there was marginal difference between groups regarding patients who required invasive mechanical ventilation (21% with aspirin vs. 22% with usual care, RR 0.96, 95% CI 0.90-1.03, p=0.23). However, aspirin was associated with decreased length of admission (8 days vs. 9 days) and increased likelihood of hospital discharge within 28 days (75% vs. 74%, p=0.0062) compared to usual care. Overall, aspirin did not show a significant difference in all-cause mortality among COVID-19 patients and its use in addition to routine thromboprophylaxis may be discouraged.

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