Recurrences and bleeding during extended treatment of patients with venous thromboembolism: results of the international, prospective, observational WHITE study

BACKGROUND: Little data are available on real-life long-term treatments after a venous thromboembolism (VTE), and on recurrent VTE or bleeds events during treatments. METHODS: We investigated the complications occurring during follow-up (FU) in VTE patients who had received the treatment decisions given by the clinical centers, active in 7 countries (China, Czechia, Poland, Portugal, Russia, Slovakia, Tunisia), which participated in the international, prospective, observational WHITE study. RESULTS: FU information was collected in 1004 patients, recruited by 62 clinical centers (17 centers did not participate in FU collection). Extended treatments were proposed to 811 patients: direct oral anticoagulants (DOACs) (475), sulodexide (202), antiplatelet agents (73), vitamin K antagonists (VKAs) (45), low molecular weight heparin (LMWH) (16). All specific treatments were stopped in the remaining 193 patients. Patients who during FU used treatments different than those prescribed by the local investigators (263) or for other causes (26) were excluded from analysis. 50 primary events occurred throughout 1044 years FU in 715 patients, 4.8 incidence (×100 patient-years) [3.8 for recurrences, and 0.96 for bleeding (major or clinically relevant)]. Primary event incidence differed according to treatments (LMWH=33.3, antiplatelets =7.6, VKAs = 6.1, DOACs = 4.7, sulodexide = 4.2, all treatment stopped = 2.5), and differed across the involved countries. CONCLUSIONS: DOACs were the most used drugs for extended treatments. Overall, the rate of primary events during FU was low. The investigators identified patients at low risk of recurrence and high bleeding risk. Sulodexide use for secondary prevention deserves further studies.