Patients with idopathic erythrocytosis have lower risk of bleedings compared to polycythemia vera

Background: Idiopathic Erythrocytosis (IE) is an absolute erythrocytosis, characterized by persistently raised hemoglobin (Hb) and hematocrit (Ht) without an identified cause and few is known regarding its clinical characteristics. The diagnosis is based on the exclusion of primary or secondary erythrocytosis. Within absolute erythrocytosis, Polycythemia Vera (PV), A primary neoplastic disease characterized by the presence of JAK2 mutations, has known to have an increased risk of thrombotic and hemorrhagic complications. We report the hemorrhagic risk of patients with IE compared to patients with PV. Methods: We report 145 patients with IE studied between 1980 and 2015 in two centres of Venetian region Italy. As controls we used 145 patients with PV, diagnosed in the same period and matched for Ht values. All patients were treated with phlebotomies, to maintain Ht below 45% and received low dose aspirin according to best clinical practice. results Results are summarized in table n. 1. IE shows A significantly better Hemorrhagic Free survival compared to PV (p=0.002). The hemorrhagic incidence rate was 0.57% pts/year in IE and 2.01% pats/year in PV (IRR=0.28). Multivariable analysis, including age, sex, platelet count at diagnosis and low-dose aspirin therapy, confirms the significant lower risk of bleedings in IE compared to PV (HR 0.27, 95% CI 0.091-0.792; p=0.017) Conclusions: IE is A poorer studied disease while PV is well-studied. PV has A bleeding incidence rate estimated of 2.9% pats/year, confirmed in the present cohort, which do not increase significantly during aspirin treatment as demonstrated in the ECLAP study. The incidence rate of hemorrhages in IE resulted about 4 times lower than in PV. Interestingly, the low-dose aspirin administration did not increase the occurrence of bleeding in both IE and PV patients. The present data suggest that prophylaxis with aspirin should be considered in IE, in the absence of contraindications.