High Plasma Homocysteine: A Risk Factor for Arterial and Venous Thrombosis in Patients with Normal Coagulation Profiles

A high plasma homocysteine concentration is associated with premature vascular disease and thrombosis. The association between high homocysteine concentrations and thrombosis in patients with a normal coagulation profile is unknown. Sixty adults (37 men and 23 women, mean age 46 years) with documented thrombosis were compared with age-and sex-matched controls. Those with risk factors for thrombosis or abnormal coagulation profiles were excluded. Homocysteine concentrations were higher in cases than controls (21.8 ± 13.8 vs 11.0 ± 4.7 μmol/L, p < 0.001). A cut point for defining high homocysteine concentrations was determined at 13 μmol/L and conferred an increased odds ratio for thrombosis overall (7.8, 95% CI 3.0-20.2, p < 0.001) as well as in men (8.9, 95% CI 3.0-26.1; p < 0.001) and women (37.8, 95% CI 6.5-213.9; p < 0.01). A high plasma homocysteine is a risk factor for thrombosis in patients with a normal coagulation profile. This common abnormality should be sought in patients with otherwise unexplained thrombotic episodes.