Short and long-term outcomes of COVID-19-associated venous thromboembolism: a propensity score-matched cohort study

Venous thromboembolism (VTE) is a recognized complication of SARS-CoV-2 infection, but its clinical features and both sort- and long-term outcomes remain incompletely characterized. We aimed to compare the clinical profile and outcomes of patients with VTE with and without recent COVID-19. We conducted a prospective cohort study including 2012 patients with objectively confirmed VTE. COVID-19-associated VTE was defined as VTE diagnosed within 30 days of a microbiologically confirmed SARS-CoV-2 infection. Clinical characteristics, treatment, and outcomes were compared between groups. Propensity score matching (1:1) and competing risk models were used to adjust for confounding. The primary outcomes-assessed at both 30 days and 365 days-included all-cause mortality, major bleeding, and VTE recurrence. A total of 272 patients (13.5%) had COVID-19-associated VTE. Compared with non-COVID cases, these patients more often had pulmonary embolism, higher D-dimer levels, and greater use of unfractionated heparin. At 30 days, COVID-19 was associated with increased mortality (HR 2.29; 95% CI 1.19-4.40) and major bleeding (HR 2.11; 95% CI 1.06-4.21). At one year, the bleeding risk remained higher (HR 1.54; 95% CI 1.02-2.33), while VTE recurrence was lower (HR 0.34; 95% CI 0.13-0.94). These results were consistent after propensity score matching. COVID-19-associated VTE is linked to worse short-term outcomes, including early mortality and bleeding, and to a persistently elevated bleeding risk at one year. Lower recurrence rates support the consideration of COVID-19 as a transient provoking factor.