An international survey of clinicians regarding their management of venous thromboembolism following the initial 3–6 months of anticoagulation

After an initial treatment period for venous thromboembolism (VTE), indefinite anticoagulation may be considered, depending upon individual risks. The aim of the study was to determine if there is consensus amongst clinicians that manage VTE regarding which patients require 3–6 months versus indefinite anticoagulation. The importance of VTE site and severity in decision making was also evaluated. An international survey of clinicians involved in VTE management was undertaken. Respondents were asked about long-term treatment of six patients that had completed 3–6 months initial anticoagulation. These included four cases of VTE not associated with a major reversible risk factor and two control cases; one unprovoked VTE and one VTE associated with a major reversible risk factor. For consensus, there was a pre-defined equivalence boundary whereby at least 70% of clinicians had to decide either to stop or consider indefinite anticoagulation for each case. 351 responses were collected. In the control cases, there was a ≥ 95% consensus on long-term management (stop versus indefinite anticoagulation). In three of the four test cases, there was no consensus about duration of anticoagulation. In case 3, 78% (99% confidence interval 73–84%) would stop anticoagulation after 3–6 months. When analysed by grade or specialty of doctor, a lack of consensus remained. Opinion on whether site or severity of VTE influenced decision making was variable. For patients with unprovoked VTE or VTE associated with a major transient risk factor there is treatment consensus. For the remainder, there is a lack consensus regarding the need for indefinite anticoagulation.