Duration of anticoagulation following venous thromboembolism: a meta-analysis

ContextPatients with venous thromboembolism (VTE) are susceptible to recurrent events, but whether prolonging anticoagulation is warranted in patients with VTE remains controversial.ObjectiveTo review the available evidence and quantify the risks and benefits of extending the duration of anticoagulation in patients with VTE.Data SourcesPubMed, EMBase Pharmacology, the Cochrane database, clinical trial Web sites, and a hand search of reference lists.Study SelectionIncluded studies were randomized controlled trials with results published from 1969 through 2004 and evaluating the duration of anticoagulation in patients with VTE that measured recurrent VTE. Excluded studies were those enrolling only pure populations of high-risk patients. Two independent reviewers assessed each article for inclusion and exclusion criteria, with adjudication by a third reviewer in cases of disagreement. Fifteen of 67 studies were included in the analysis.Data ExtractionTwo independent reviewers performed data extraction using a standardized form, with adjudication by the remainder of the investigators in cases of disagreement. Data regarding recurrent VTE, major bleeding, person-time at risk, and study quality were extracted.Data SynthesisIf patients in the long-term therapy group remained receiving anticoagulation, the risk of recurrent VTE with long- vs short-term therapy was reduced (weighted incidence rate, 0.020 vs 0.126 events/person-year; rate difference, −0.106 [95% confidence interval {CI}, −0.145 to −0.067]; P