Leukocyte Count of Prognostic Value in Platelet Disorder
Leukocytes, but not platelets, predict vascular events in essential thrombocythemia
MONDAY, May 5 (HealthDay News) -- Among patients with essential thrombocythemia, an elevated leukocyte count at the time of diagnosis is associated with an increased risk of thrombotic events, suggesting that leukocyte count could be used for risk stratification, according to an article released online April 28 in advance of publication in the June issue of the Journal of Clinical Oncology.
Alessandra Carobbio, of Ospedali Riuniti in Bergamo, Italy, and colleagues followed 657 patients with essential thrombocythemia for a median of 4.5 years in order to investigate whether baseline leukocytosis predicted thrombotic events such as ischemic stroke, transient ischemic attack, myocardial infarction, peripheral arterial thrombosis and venous thromboembolism.
Statistical analysis confirmed that age and prior thrombotic events were independent risk factors for thrombosis. In addition, the risk of thrombosis rose with increasing levels of leukocytosis, the researchers report. In contrast, platelet number and JAK2 allele burden did not impact thrombotic risk. In low-risk patients, baseline leukocytosis conferred a risk similar to that of patients designated as high-risk by conventional methods. The researchers propose that a cutoff leukocyte value of 9.4 x 10⁹/L be used for risk-stratification.
This study "provides further evidence to strengthen the concept of leukocytosis as a risk factor for thrombosis, and suggests that leukocyte counts may be of prognostic value mostly in low-risk patients with essential thrombocythemia," the authors conclude.