Recurrent venous thromboembolism in a Spanish population: Incidence, risk factors, and management in a hospital setting

The major concern in the management of venous thromboembolism is the propag ation of thrombus and rethrombosis. The incidence of recurrences and the du ration of oral anticoagulant therapy in these patients are still controvers ial. The aim of this study was to determine the incidence, timing, and outc ome of further thrombotic events after an initial episode of venous thrombo embolism ina hospital setting. In addition, we evaluated potential risk fac tors for all these outcomes, This was designed as a retrospective analysis of all patients admitted to our Center with an episode of deep vein thrombo sis and/or pulmonary embolism between 1986 and 1996. The patients included in the study had to be treated with unfractionated heparin or low molecular weight heparin, followed by at least 3 months of oral anticoagulants, Natu ral and acquired hemostasis inhibitors were assayed in patients aged less t han 50 years. A total of 290 patients with a first episode of venous thromb oembolism were included in the study. A total of 33 patients (11.9%, 95% co nfidence interval, 7.4-14.6) had recurrent episodes. The cumulative inciden ce of recurrent venous thromboembolism after 2, 5, and 10 years was 7.68, 1 0, and 12.4%, respectively. The incidence of rethrombosis was significantly higher in patients with idiopathic venous thromboembolism than in patients with secondary thrombosis, Abnormalities of hemostasis were found in 54.5% (95% confidence interval, 37.6-71.4) of the patients with recurrences and under the age of 50 years. Three of seven patients who stopped anticoagulan t therapy after the second episode presented a third thrombotic event, In o ur study population, those patients with idiopathic venous thromboembolism seem to have an increased risk of recurrence. The second thrombotic episode occurs more frequently during the following 2 years after cessation of ant icoagulation therapy. Our findings strongly support the use of long-term an ticoagulant therapy in patients with recurrent venous thromboembolism. (C) 1999 Elsevier Science Ltd. All rights reserved.