Elevated d-dimer levels predict recurrence in patients with idiopathic venous thromboembolism: a meta-analysis

Background: The evidence on the optimal duration of treatment in patients with an idiopathic venous thromboembolic event (VTE) is inconclusive. d-dimer testing to predict recurrent VTE has been evaluated in several studies. Objectives: We performed a meta-analysis of studies of patients with idiopathic VTE treated with oral anticoagulation therapy (OAT) to assess the prognostic value of elevated d-dimer levels 1 month after discontinuation of OAT for VTE recurrence. Patients/Methods: The MEDLINE, EMBASE and Cochrane databases were searched to identify relevant studies. Studies were eligible for inclusion if they included patients with idiopathic VTE and in addition reported results for this group separately, had measured d-dimer approximately 1 month after discontinuation of OAT and had reported on recurrence of VTE. A random-effects model was used to pool study results. Results: Data from four studies (1539 patients) were included in the current analysis. All studies reported on the number of recurrent events in the normal and elevated d-dimer groups. Overall, 125 of 751 patients (16.6%) with elevated d-dimer levels experienced recurrent VTE during the period of follow-up compared with 57 of 788 patients (7.2%) with normal d-dimer levels. Elevated d-dimer levels were significantly associated with recurrent VTE (odds ratio , 2.36; 95% CI, 1.65 to 3.36). Conclusions: Elevated d-dimer levels measured 1 month after discontinuation of OAT identify patients with idiopathic VTE at higher risk of recurrence.