Background: COVID-19 is an infectious illness, featured by an increased risk of thromboembolism. However, no standard antithrombotic therapy is currently recommended for patients hospitalized with COVID-19. The aim of this study was to evaluate safety and efficacy of additional therapy with ASA over prophylactic anticoagulation (PAC) in patients hospitalized with COVID-19 and its impact on survival.

Methods and Results: a total of 8.168 patients hospitalized for COVID-19 were enrolled in a multicenter-international prospective registry (HOPE COVID-19). Clinical data and inhospital complications, including mortality, were recorded. Study population included patients treated with PAC or with PAC and ASA. A comparison of clinical outcomes between patients treated with PAC versus PAC and ASA was performed using an adjusted analysis with propensity score matching. Of 7.824 patients with complete data, 360 (4.6%) received PAC and ASA a nd 2 .949 ( 37.6%) P AC. P ropensity-score matching yielded 298 patients from each group. In the propensity score-matched population, cumulative incidence of in-hospital mortality was lower in patients treated with PAC and ASA versus PAC (15% versus 21%, Log Rank P=0.01). At multivariable analysis in propensity matched population of patients with COVID-19, including age, sex, hypertension, diabetes, kidney failure, and invasive ventilation, ASA treatment was associated with lower risk of in-hospital mortality (hazard ratio [HR], 0.62; [95% CI 0.42-0.92], P=0.018).

Conclusions: combination PAC and ASA was associated with lower mortality risk among patients hospitalized with COVID-19 in a propensity score matched population compared to PAC alone.