Summary
Bleeding is a common and feared complication of oral anticoagulant therapy. Several
prediction models have been recently developed, but there is a lack of evidence in
patients with venous thromboembolism (VTE). The aim of this study was to validate
currently available bleeding risk scores during long-term oral anticoagulation for
VTE. We retrospectively included adult patients on vitamin K antagonists for VTE secondary
prevention, followed by five Italian Anticoagulation Clinics (Cuneo, Livorno, Mantova,
Napoli, Varese), between January 2010 and August 2012. All bleeding events were classified
as major bleeding (MB) or clinically-relevant-non-major-bleeding (CRNMB). A total
of 681 patients were included (median age 63 years; 52.0% female). During a mean follow-up
of 8.82 (± 3.59) months, 50 bleeding events occurred (13 MB and 37 CRNMB), for an
overall bleeding incidence of 9.99/100 patient-years. The rate of bleeding was higher
in the first three months of treatment (15.86/100 patient-years) than afterwards (7.13/100
patient-years). The HAS-BLED showed the best predictive value for bleeding complications
during the first three months of treatment (area under the curve [AUC] 0.68, 95% confidence
interval [CI] 0.59–0.78), while only the ACCP score showed a modest predictive value
after the initial three months (AUC 0.61, 95%CI 0.51–0.72). These two scores had also
the highest sensitivity and the highest negative predictive value. None of the scores
predicted MB better than chance. Currently available bleeding risk scores had only
a modest predictive value for patients with VTE. Future studies should aim at the
creation of a new prediction rule, in order to better define the risk of bleeding
of VTE patients.
Keywords
Bleeding risk scores - long-term follow-up - venous thromboembolism - vitamin K antagonist