Patients aged 65 years or older were at an increased risk for major bleeding (MB) and clinically relevant nonmajor bleeding (CRNB) with anticoagulation with vitamin K antagonists for the treatment of venous thromboembolism (VTE), according to the results of a prospective study published in Blood Advances.

Although older patients are known to have an increased risk for bleeding compared with younger patients with anticoagulation, the clinical impact of this bleeding among older patients is not well understood.

This multicenter cohort study prospectively evaluated data of 981 patients aged 65 and older with acute VTE from the Swiss Venous Thromboembolism Cohort Study 65+ conducted between 2009 and 2013. The endpoints were MB or CRNMB events up to 36 months.

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MB for this study was defined as bleeding that was fatal, at a critical site, lead to a decrease in hemoglobin by 20 g/L or more, or required a transfusion of 2 or more whole blood or red cells. CRNMB included events that were not MB, but required consultation or evaluation by a physician or the emergency department.

The median age of the cohort was 75 and 53% of patients were male. The VTE event was unprovoked among 61% of patients, provoked among 22%, and related to active cancer in 64%. Anticoagulation was achieved by vitamin K antagonists among 88% of patients and the median duration of anticoagulation was 9 months.

Given that this study was conducted prior to the introduction and adoption of direct oral anticoagulants (DOACs) as the standard of care, the authors acknowledged that these findings may not be extrapolated to older patients treated with DOACs rather than vitamin K antagonists.

The rate of MB was 8.5 per 100 patient-years. There were a total of 100 MB events, with 15% intracranial and 6% fatal. The most common sites of MB were gastrointestinal, followed by intramuscular, intracranial, and cutaneous/subcutaneous. Hospitalization was required among 79% of patients with MB, surgical intervention among 18%, and permanent discontinuation among 15%.

CRNMB occurred at a rate of 13.4 per 100 patient-years. There were a total of 125 CRNMB events, with 15% of patients requiring hospitalization. The most common sites were cutaneous/subcutaneous, followed by urogenital, gastrointestinal, and epistaxis.

The risk of bleeding was highest during the initial period of anticoagulation and decreased over time, with 47% of MB events and 34% of CRNMB events occurring during the first 3 months of anticoagulation.

The risk of MB was significantly higher for active cancer (subhazard ratio [SHR], 1.81; 95% CI, 1.12-2.93; P =.016) and low levels of physical activity (SHR, 1.88; 95% CI, 1.19-2.98; P =.007). There was an increased risk for CRNMB among patients at a high risk for falls (SHR, 2.04; 95% CI, 1.39-3.00; P <.001).

There was no association for MB or CRNMB for factors such cardiac disease, diabetes mellitus, history of MB, recent surgery, anemia, or thrombocytopenia.

The authors concluded that “Older patients’ anticoagulation for VTE had a high incidence of MB and CRNMB, and these bleeding episodes caused a great burden of disease.” They recommended that clinicians “carefully weigh the risks/benefits of extended anticoagulation in the older population with VTE.”


Ferrazzini E, Méan M, Stalder O, et al. Incidence and clinical impact of bleeding events in older patients with acute venous thromboembolism. Blood Adv. 2023;7:205-213. doi: 10.1182/bloodadvances.2022007263