Background: Venous thromboembolism (VTE) manifesting as deep vein thrombosis (DVT) and pulmonary embolism (PE) remains a common vascular disease with high mortality and morbidity. Our aim was to study the clinical spectrum of VTE, assess its incidence in the general population, and evaluate potential risk factors.
Methods: Prospective cohort study with nested case-control analysis using the General Practice Research Database (1994-2000). Venous thromboembolism was newly diagnosed in 6550 patients. Cases were compared with a random sample of 10,000 controls and frequency-matched by age, sex, and year.
Results: The incidence rate of VTE was 74.5 per 100,000 person-years. Overweight, varicose veins, inflammatory bowel disease, cancer, and oral corticosteroid use were associated with a greater risk of VTE. Ischemic heart disease, heart failure, and cerebrovascular diseases were associated with an increased risk of PE but not with DVT. Venous thromboembolism was strongly associated with fractures (odds ratio [OR], 21.3; 95% confidence interval [CI], 15.7-28.9) and surgery (OR, 25.0; 95% CI, 14.4-43.5). In women, the risk of VTE was 1.9 (95% CI, 1.5-2.3) among those receiving opposed hormone therapy (in which the woman takes estrogen throughout the month and progesterone for 10-14 days later in the month) and 1.9 (95% CI, 1.4-2.5) among those taking oral contraceptives. Cancer and cerebrovascular diseases presented a greater relative risk of fatal PE compared with nonfatal PE.
Conclusions: Overweight, varicose veins, cancer, inflammatory bowel disease, fractures, surgery, and use of oral corticosteroids, oral contraceptives, and opposed hormone therapy were independent risk factors for both DVT and PE. The magnitude of the association with some risk factors varied between DVT and PE, as well as between fatal and nonfatal PE.