The long-term recurrence risk of patients with unprovoked venous thromboembolism: an observational cohort study

SummaryBackground The long-term recurrence risk (ltRR) of venous thromboembolism (VTE) is uncertain. Objective to assess the ltRR of patients with first unprovoked VTE. Patients/Methods Patients were classified into 3 categories; distal deep-vein thrombosis (DVT), proximal DVT, or pulmonary embolism (PE), i.e. PE associated with DVT or isolated PE. Patients with major thrombophilia or antithrombotic therapy were excluded. End point was recurrent symptomatic VTE. Results 839 patients were followed for a median of 7.7 years. VTE recurred in 263 patients (31%). After10 and 20 years, the cumulative ltRR was 32% (95% confidence interval [CI] 29 to 36) and 44% (95% CI 38 to 49) with 3.9 (95% CI 3.3 to 4.6) and 3.3 (95% CI 2.7 to 4.0) events per 100 patient-years, respectively. The adjusted hazard ratio was 2.1 (95% CI 1.4 to 3.2) and 2.1 (95% CI 1.4 to 3.2) for patients with proximal DVT or PE compared to patients with distal DVT and was 2.1 (95% CI 1.6 to 2.9) for men compared to women. At ten years, 4.7 (95% CI 3.8 to 5.8) events per 100 patient-years occurred in men with proximal DVT or PE, 2.4 (95% CI 1.2 to 4.4) in men with distal DVT, 1.9 (95% CI 1.2 to 2.8) in women with proximal DVT or PE and 0.9 (95% CI 0.2 to 1.9) in women with distal DVT. Conclusion The ltRR of patients with first unprovoked VTE is high and dependent upon sex and VTE site. This article is protected by copyright. All rights reserved.