Homocysteine levels in polycythaemia vera and essential thrombocythaemia

Patients with polycythaemia vera (PV) or essential thrombocythaemia (ET) ha ve an increased risk of arterial and Venous thromboembolic complications. S ince hyperhomocysteinaemia (HHC) is a risk factor for vascular disease, we investigated the frequency of HHC in these disorders and analysed a possibl e association of elevated plasma homocysteine levels with vascular complica tions, In the cohort of 134 patients from Vienna (69 female, 65 male, media n age 65.5 years, range 21-91 years) with PV (n = 74) or ET (n = 60), plasm a homocysteine levels were significantly higher compared to 134 healthy con trols. Median homocysteine lever was 12.3 mu mol/l (range 3.5-48.4 mu mol/l ) in patients with PV or ET and 8.9 mu mol/l (range 4.8-30.5 mu mol/l) in n ormal controls (P < 00001). In addition to the 134 patients from Vienna, 48 patients (28 female, 20 male; median age 66.5 years, range 24-82) from Vic enza with PV (n = 25) or ET (n = 23) were included to evaluate the impact o f HHC on the risk of thrombosis, Of 59 patients with HHC (44 from Vienna an d 15 from Vicenza) 18 (31%) had a history of arterial and 10 (17%) of venou s thrombosis. Of 123 patients with normal homocysteine levels, 30 (24%) had arterial and 16 (13%) had venous thromboses. The difference between the tw o groups was statistically not significant. Even though mild to moderate HH C occurred in a larger number of patients with PV or ET and thrombosis, it can presently not be regarded as an additional risk factor for thrombosis.