regular expression for validating email address - Validating date c
Women who met two or more criteria and all men were classified as high risk.
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)).
Some patient subgroups with major provoking factors (eg, post-surgical VTE) have a low risk of recurrent VTE (1% at one year)1 and anticoagulants can be safely discontinued after short term treatment.2 However, more than 50% of patients with VTE do not have a major provoking factor.3 In these patients with unprovoked VTE, the risk of recurrent VTE is substantially higher; up to 10% in the first year after stopping short term treatment, 5% in the subsequent year,4 and 30% at eight years.5 Recurrent VTE is fatal in 3.6% of cases.6Oral anticoagulant treatment is effective at reducing the risk of recurrent VTE during treatment; oral anticoagulant treatment reduces the risk of recurrent VTE by 80-90%.7 Longer term oral anticoagulant treatment likely only delays recurrent VTE compared with short term treatment.8910 The highest bleeding risks are observed during initial oral treatment.
Patients who do not bleed during this time, termed “anticoagulant experienced” patients, are at lower risk of major bleeding with ongoing treatment (1.3% per year).7 Major bleeding is fatal in 11.3% of affected patients.6Guidelines recommend long term anticoagulant treatment in patients with unprovoked VTE with non-high bleeding risks, but this is based on weak evidence (grade 2B)11 owing to closely balanced competing risks and burdens of recurrent VTE and major bleeding.
Participants were then followed for one year for recurrent VTE and major bleeding.