Question: Can a D-dimer level assess the risk of recurrent venous thromboembolism (VTE) after a course of anticoagulation therapy has been completed?
Background: The duration of anticoagulation therapy for first unprovoked VTE is uncertain. Identifying risk of recurrent VTE will help clinicians make decisions on optimal duration of anticoagulation.
Study design: Systematic review and meta-analysis.
Setting: Patients who have completed therapy for an episode of VTE without known risks.
Synopsis: Seven high-quality studies totaling 1,888 patients with first unprovoked VTE were analyzed. All patients received standardized therapy for at least three months with warfarin (Coumadin). A D-dimer had been checked in all patients between three and six weeks after stopping anticoagulation. The annual rate of VTE recurrence among patients with a positive D-dimer result was 8.9% (confidence interval (CI), 5.8% to 11.9%) compared with 3.5% (CI, 2.7 to 4.3%) for those with a negative result.
False-positive or false-negative D-dimer results could have occurred due to the heterogeneity in duration of anticoagulation and timing of D-dimer testing among the various studies. Since none of the studies were blinded to a history of VTE, there is potential for outcome ascertainment bias due to studying a sample deemed susceptible to disease recurrence.
Bottom line: D-dimer testing holds promise in identifying risk of VTE recurrence and could aid therapeutic decision-making regarding duration of anticoagulation.
Citation: Ann Intern Med. 2008;149:481-490
–Reviewed for the eWire by Rebecca Allyn, MD, Smitha Chadaga, MD, Mary Dedecker, MD, Vignesh Narayanan, MD, Eugene S. Chu, MD, Division of Hospital Medicine, Denver Health and Hospital Authority