Validating telephone numbers
Participants were then followed for one year for recurrent VTE and major bleeding.
All patients provided written informed consent before participation.
Objective To prospectively validate the HERDOO2 rule (Hyperpigmentation, Edema, or Redness in either leg; D-dimer level ≥250 μg/L; Obesity with body mass index ≥30; or Older age, ≥65 years), which states that women with none or one of the criteria can safely discontinue anticoagulants after short term treatment. Setting 44 secondary or tertiary care centres in seven countries.
Participants Of 3155 consecutive eligible participants with a first unprovoked venous thromboembolism (VTE, proximal leg deep vein thrombosis or pulmonary embolism) who completed 5-12 months of short term anticoagulant treatment, 370 declined to participate, leaving 2785 enrolled participants. Interventions Women with none or one of the HERDOO2 criteria were classified as at low risk of recurrent VTE and discontinued anticoagulants (intervention arm), whereas anticoagulant management for high risk women (≥2 HERDOO2 criteria) and men was left to the discretion of the clinicians and patients (observation arm).
In the primary analysis, 17 low risk women who discontinued anticoagulants developed recurrent VTE during 564 patient years of follow-up (3.0% per patient year, 95% confidence interval 1.8% to 4.8%).
In 323 high risk women and men who discontinued anticoagulants, 25 had VTE during 309 patient years of follow-up (8.1%, 5.2% to 11.9%), whereas in 1802 high risk women and men who continued anticoagulants 28 had recurrent VTE during 1758 patient years of follow-up (1.6%, 1.1% to 2.3%).
Results Of 1213 women, 631 (51.3%) were classified as low risk and 591 discontinued oral anticoagulant treatment.Hence, the clinical question of who should continue taking anticoagulants indefinitely and who can safely discontinue them after short term treatment for unprovoked VTE remains a high research priority.910 To answer this important question, the long term risks and burdens of recurrent VTE must be balanced against the long term risks and burdens of oral anticoagulant treatment, especially major bleeding.The International Society on Thrombosis and Haemostasis suggests that it is safe to discontinue anticoagulants if the risk of recurrent VTE is less than 5% at one year after discontinuing treatment.12 To date, no clinical decision rules 131415 designed to achieve these standards have been prospectively validated.Patients were excluded if they were unable or unwilling to provide informed consent; were aged less than 18 years; had already discontinued oral anticoagulant treatment; required ongoing anticoagulation (eg, mechanical heart valves, atrial fibrillation, inferior vena cava filter, or had known high risk thrombophilia before enrolment.High risk thrombophilia included deficiency of protein S, protein C, or antithrombin, persistently positive antiphospholipid antibodies, or two or more known other thrombophilic defects (eg, homozygous for factor V Leiden mutation or prothrombin gene mutation, or compound heterozygous for factor V Leiden and prothrombin gene mutation)); were geographically inaccessible for follow-up; had planned to use exogenous oestrogen (patch, ring, oral contraceptive, or hormone replacement therapy) if anticoagulant treatment was discontinued; or had pregnancy associated index VTE (antepartum or postpartum (within 12 weeks of delivery)).