Clinically relevant non-major bleeding with oral anticoagulants: non-major may not be trivial.

The clinical benefit of anticoagulant treatment for various indications is offset by the risk of bleeding. The impact of bleeding related to vitamin K antagonist (VKA) use, in terms of patients’ discomfort or temporary disability and in terms of both medical and socio-economic resources is not negligible1–4. However, the majority of studies have focused on major bleeding, used obsolete definitions of bleeding and have not distinguished between clinically relevant non-major bleeding (CRNMB) and minor events2,3. The International Society on Thrombosis and Haemostasis provided a standard definition of CRNMB in 2015 as those events that are not major but require any kind of medical intervention5. Over the last decade, many randomised phase III studies on direct oral anticoagulants (DOAC) have reported incidences of CRNMB in patients treated for atrial fibrillation or venous thromboembolism6–14. The rates of CRNMB in these studies have varied between 4 and 12%15–17. In the observational studies, the rates of major bleeding were about 5% and those of CRNMB varied between 10 and 20%18–20. Overall, compared with major bleeds, CRNMB tend to occur more frequently and are associated with a lower mortality6–14,19. However, the burden of care arising from CRNMB, for both the patient and the health system, is difficult to estimate in clinical practice. We carried out a prospective, observational, multicentre, cohort study to assess the clinical characteristics, management and outcomes of CRNMB occurring in patients while on oral anticoagulants.