Clinical features of venous insufficiency and the risk of venous thrombosis in older people.

Venous thrombosis is common in older age, with an incidence of 0·5-1% per year in those aged >70 years. Stasis of blood flow is an important contributor to the development of thrombosis and may be due to venous insufficiency in the legs. The risk of thrombosis associated with clinical features of venous insufficiency, i.e., varicose veins, leg ulcers and leg oedema, obtained with a standardized interview was assessed in the Age and Thrombosis Acquired and Genetic risk factors in the Elderly (AT-AGE) study. The AT-AGE study is a case-control study in individuals aged 70 years and older (401 cases with a first-time venous thrombosis and 431 control subjects). We calculated odds ratios (ORs) and corresponding 95% confidence intervals (CI) adjusted for age, sex and study centre. Varicose veins and leg ulcer were associated with a 1·6-fold (95% CI 1·2-2·3) and 3·3-fold increased risk of thrombosis (95% CI 1·6-6·7), respectively, while the risk was increased 3·0-fold (95% CI 2·1-4·5) in the presence of leg oedema. The risk of thrombosis was highest when all three risk factors occurred simultaneously (OR: 10·5; 95% CI 1·3-86·1). In conclusion, clinical features of venous insufficiency, i.e., varicose veins, leg ulcers and leg oedema, are risk factors for venous thrombosis in older people.