Incidence and risk factors for bilateral deep venous thrombosis of the lower limbs.

The incidence of bilateral deep venous thrombosis in patients with single limb or bilateral symptoms was determined using duplex scan examination. In a prospective study, 157 inpatients with clinical suspicion of deep venous thrombosis underwent duplex scan evaluation of the lower extremities. Demographic characteristics, physical examination data, and risk factor information were collected. In all, 57 (36.3%) patients evaluated presented echographic evidence of acute deep venous thrombosis. Forty-six individuals presented unilateral thrombosis, and 11 patients presented bilateral disease (19.3% of all thrombosis, 7.0% of all patients). Sensitivity and specificity of clinical examination in identifying bilateral thrombosis was 27.2% and 93.3%, respectively. For the risk factors evaluated, active human immunodeficiency virus disease and iliofemoral thrombosis presented an increased risk for bilateral thrombosis (P = .045 and P = .049, respectively). The high incidence of bilateral deep venous thrombosis justifies bilateral duplex scan examination. Active human immunodeficiency virus disease and proximal thrombosis were risk factors for bilateral disease.