title: Leukocytosis as a major thrombotic risk factor in patients with polycythemia vera.
abstract: In polycythemia vera, vascular risk assessment is based on age and thrombotic history, while the role of other potential predictors of this risk is still uncertain. Thus, we exploited the large database collected by the observational study of the European Collaboration on Low-Dose Aspirin in Polycythemia Vera (ECLAP) to investigate the association of hematologic variables and cardiovascular risk factors with the thrombotic risk. Among 1638 polycythemic patients followed for 2.7 +/- 1.3 years, there were 205 thromboses. Subjects with hypertension had a mild nonsignificant increase in the risk of arterial thrombosis, while this risk was significantly increased by smoking (hazard ratio [HR], 1.90; 95% confidence interval [CI], 1.15-3.14; P = .012). The time-dependent analysis adjusted for potential confounders showed that patients with a white blood cell count above 15 x 10(9)/L, compared with those with a white blood cell count below 10 x 10(9)/L, had a significant increase in the risk of thrombosis (HR, 1.71; 95% CI, 1.10-2.65; P = .017), mainly deriving from an increased risk of myocardial infarction (HR, 2.84; 95% CI, 1.25-6.46; P = .013). Thus, leukocyte count may help in defining the vascular risk of polycythemic subjects.
authors.affiliation: Catholic University School of Medicine, Institute of Internal Medicine and Geriatrics, Haemostasis Research Center, Rome, Italy. rlandolfi@rm.unicatt.it
authors.forename: Raffaele
authors.initials: R
authors.lastname: Landolfi
authors.forename: Leonardo
authors.initials: L
authors.lastname: Di Gennaro
authors.forename: Tiziano
authors.initials: T
authors.lastname: Barbui
authors.forename: Valerio
authors.initials: V
authors.lastname: De Stefano
authors.forename: Guido
authors.initials: G
authors.lastname: Finazzi
authors.forename: Rosamaria
authors.initials: R
authors.lastname: Marfisi
authors.forename: Gianni
authors.initials: G
authors.lastname: Tognoni
authors.forename: Roberto
authors.initials: R
authors.lastname: Marchioli
mesh_terms: D000368:Aged; D001241:Aspirin / Q000627:therapeutic use; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007958:Leukocyte Count; D007964:Leukocytosis / Q000150:complications* / Q000453:epidemiology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011087:Polycythemia Vera / Q000150:complications* / Q000188:drug therapy / Q000453:epidemiology / Q000473:pathology*; D012307:Risk Factors; D013927:Thrombosis / Q000453:epidemiology / Q000209:etiology* / Q000473:pathology*
chemical_list: D001241:Aspirin