Vitamin K Antagonist Versus Direct Oral Anticoagulant Treatments in Hemophilia

Hemophilia is a rare X-linked bleeding disorder responsible for deficiency of coagulation factor VIII (FVIII) or IX (FIX). The main clinical manifestation is increased bleeding throughout the life which is directly correlated to the severity of the hemophilia, either mild (FVIII/FIX: 6-40), moderate (FVIII/FIX: 1-5%), or severe (FVIII/FIX\<1%). Thanks to new therapies and long-term specialized follow-up by hemophilia treatment centers (HTCs), the life expectancy of patients with hemophilia (PWH) has improved considerably, even reaching that of the general population (1). Healthcare professionals are so more confronted to PWH with age-related pathologies, in particular cardiovascular pathologies such as atrial fibrillation, acute coronary syndromes or thromboembolic events (arterial or venous). It is now recommended in PWH that an anticoagulant treatment (AC) be prescribed as in the general population (2,3,4). The recently published COCHE study demonstrated a significantly increased risk of bleeding in PWH receiving antithrombotic treatment. This bleeding risk depended significantly on the type of antithrombotic treatment, which was higher for anticoagulant vs antiplatelet drugs, on basal levels of FVIII or FIX, and on the HAS-BLED score (5). Nowadays in the general population, among anticoagulant drugs, direct oral anticoagulants (DOACs) are preferred to vitamin K antagonist (KVA), thanks to their reduced risk of bleeding particularly intracerebral bleeding and better anticoagulant stability over time (6). However, we do not yet know precisely whether DOACs could occupy the same place in the PWH population because of the lack of evidence-based data due to the very small number of these patients, although some authors already recommend them over KVA. The KADOAH study was therefore set up to try to provide initial elements for future recommendations. Its main objective was to compare the level of bleeding risk of PWH treated with VKA vs DOACs.