Superficial venous thrombosis and venous thromboembolism: a large, prospective epidemiologic study.

Background: Superficial venous thrombosis (SVT) is perceived to have a benign prognosis.

Objective: To assess the prevalence of venous thromboembolism in patients with SVT and to determine the 3-month incidence of thromboembolic complications.

Design: National cross-sectional and prospective epidemiologic cohort study.