The predictive value of vascular risk factors and gender for the development of thrombotic complications in essential thrombocythemia.

The impact of the cardiovascular risk factors smoking, hypertension, hypercholesterolemia, and diabetes mellitus on the risk of thrombotic complications was evaluated retrospectively in 132 patients with essential thrombocythemia (ET). The median age at diagnosis was 51 years, and the median follow-up time was 65 months. Sixty-three out of 132 patients (48%) had one or more vascular risk factors, whereas 69 patients (52%) had no risk factors. Thirty-two patients were smokers, 27 had hypertension, 21 hypercholesterolemia, and four diabetes mellitus. During the follow-up, 53 patients (40%) had 98 arterial thrombotic events, half of which were disturbances of cerebral circulation. Fifteen patients (11%) experienced 27 venous thrombotic events. The presence of one or more vascular risk factors increased the risk of arterial thrombotic complications. Of the patients, 52% with one or more vascular risk factors and 29% of those without any risk factors had arterial thrombosis (P = 0.01). In multivariate analysis the only independent risk factor was smoking (P = 0.01). Male gender increased the risk of arterial thrombosis significantly. Thirty-six out of 62 men (58%) but only 17 out of 70 women (24%) had an arterial complication (P < 0.001). Smoking had a strong predictive value for the development of arterial complications in women but not in men. Among women 9/15 (60%) of the smokers and 12/82 (15%) of the non-smokers experienced arterial thrombosis (P = 0.002), whereas among men no difference between smokers and non-smokers could be found. According to the present findings, the male gender should be regarded as a risk factor when deciding about the indication for treatment. Smoking should be discouraged especially among women with ET.