Clinical study recommends against using antithrombotic therapy in ill outpatients with COVID-19

December 2022 Clinical practice Nalinee Pathak
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The results of the PREVENT-HD trial show that routine antithrombotic use did not improve clinical outcomes in high-risk, medically ill outpatients with SARS-CoV-2 infection. These data were presented at the American Heart Association Scientific Sessions.

The clinicians had hypothesised that early thrombo-prophylactic dosing in higher-risk outpatients with COVID-19 might lower the incidence of venous and arterial thrombotic events, reduce pulmonary thrombosis and worsening of pulmonary function and eventually reduce mortality.


The randomised, double-blind, placebo-controlled study enrolled 1,284 (mean age, 56 years) COVID-19 outpatients across 14 health networks in the US. The participants were tested for COVID-19 and one additional risk factor before virtual admission in the study. All the participants were randomly assigned to receive either rivaroxaban or a placebo. The study’s primary endpoint was the first occurrence of a composite endpoint of symptomatic VTE, MI, stroke, acute limb ischemia, non-central nervous system systemic embolisation, all-cause hospitalisation and all-cause mortality at 35 days.

Main Findings

No significant differences were observed between the treatment and placebo arms for the occurrence of the primary composite endpoint at 35 days (HR = 0.75; 95% CI, 0.35-1.58; P = .439). However, in a post hoc analysis, a reduction in the rate of symptomatic VTE and arterial thrombotic events was seen in the rivaroxaban group (log-rank P = .025).


The findings of the PREVENT-HD study do not recommend using any antithrombotic therapy for outpatients with COVID-19.


Piazza G, et al. LBS.07: Preventing Limb Loss Through Vascular Interventions and Venous Therapies. Presented at: American Heart Association Scientific Sessions; Nov. 5-7, 2022; Chicago (hybrid meeting).