PB0042 - Antithrombotics and antihistamine use correlated with increased COVID-19 severity. Antithrombotics and antihistamine use correlated with increased COVID-19 severity.

Background: Many medications have been investigated for use in COVID-19 with anticoagulants being recommended as thromboprophylaxis in hospitals.

Aims: To investigate the effect of prophylactic and prescribed medication on COVID-19 severity.

Methods: An online survey was used to collect patient data relating to medication use prior to COVID-19 diagnosis in recovered patients. Statistics were performed using one-way ANOVA and t-test. This was an international retrospective cohort study approved by the Royal College of Surgeons in Ireland Human Research Ethics Committee.

Results: 685 participants representing 32 countries responded (age range 18-78 yrs). Antiplatelet and antithrombotic medication was associated with more severe disease, (28% severe vs. 8% mild). Aspirin and ibuprofen use after diagnosis was associated with increased length of disease; (aspirin 54.5 ± 3.1 days; control 34.8 ± 2.7 days, (P < 0.05); ibuprofen 54.7 ± 6.6 days; control 31.8 ± 2.8 days, P< 0.05).

There was an increase in disease severity for patients taking antihistamines both before and after diagnosis (severe 28%, mild 7%; severe 33% mild 10%, respectively). Antihistamine use was associated with longer disease presentation in both groups (before diagnosis: antihistamine 47.5 ± 7.9 days, control 35.4 ± 2.7 days, P< 0.01; after diagnosis 51.9 ± 5.9 days, control 30.8 ± 2.6 days P< 0.05).

Conclusion(s): We anticipated a prophylactic effect of antithrombotic use prior to infection, however, these data do not support this. The association of ibuprofen and aspirin with severe presentation is likely due to their use for patients with more severe COVID-19 or an underlying condition. Antihistamines inhibit the mast cell response which is important for fighting both the initial infection and the subsequent response. These results indicate that antithrombotics should only be used where there is an indicated thrombotic risk and antihistamines should be used with caution. Further work is required in a larger clinical study to confirm these findings.