Background: Epidemiologic studies on deep-vein thrombosis (DVT) have been mainly confined to the inpatient population. The aim of this study was to investigate the association between DVT and acquired risk factors in a large cohort of outpatients with clinically suspected DVT.
Methods: Consecutive outpatients with clinically suspected DVT were enrolled in the study. Before objective testing, all patients were interviewed by a trained physician for the presence of risk factors for DVT development. Subsequently, the presence or absence of DVT was assessed with venography.
Results: Approximately 50% of cases of DVT were considered to be secondary to a major risk factor (immobilization, trauma, and/or recent surgery). Among additional risk factors, only increased age (over 60 years), male gender, malignant neoplasm, heart failure, systemic lupus erythematosus, and arteriopathy were independently associated with the risk of acute DVT.
Conclusion: Major risk factors for venous thromboembolism are a common cause of DVT among symptomatic outpatients; therefore, the usefulness of extending DVT prophylaxis in the outpatient setting should be tested. The role of additional risk factors in the development of DVT needs to be established by properly designed studies.