Clinical Characteristics And Risk Factors For Thrombosis In Patients With BCR/ABL Negative Myeloproliferative

Objective:To analyze the clinical characteristics and the risk factors of thrombosis in patients with BCR/ABL negative myeloproliferative neoplasms and provide evidence for looking for measures to reduce complications.Methods:A retrospective study was performed among 178 patients with BCR/ABL negative myeloproliferative neoplasms from March 2005 to February 2015 to collect clinical data and laboratory examination results.We compare clinical characteristics and laboratory examination results in JAK2 V617 F mutated group with those in wild-type JAK2 V617 F group.The risk factors were analyzed using multivariate logistic regression analysis.We searched for leukocytes cut off with the best sensitivity and specificity by a receiver operating characteristic curve.Results:(1) In patients with polythemia vera,the percentage of males(P=0.002),the incidence of splenomegaly(P=0.020)and thromboembolism rate(P=0.028),the level of white blood cell counts(0.008) and platelet counts(0.003) in JAK2 V617 F mutated group were significantly higher than those in wild-type JAK2 V617 F group.In patients with essential thrombocythemia,the age(P=0.003),the incidence of splenomegaly(P <0.001),thromboembolism rate(P=0.037) and the level of platelet counts(0.009) in JAK2 V617F mutated group were significantly higher than those in wild-type JAK2 V617 F group.While in patients with primary myelofibrosis,these characteristics above were no statistically significant difference(P>0.05).(2)There were 63 thromosis events occurred in 178 patients with MPN,showing an incidence of 35.4%(63/178).A total of 37 patients with PV(50%) suffered from thrombus. The incidence of arterial thrombosis was 35.1%(26/74). The incidence of vein thrombosis was 4.9%(11/74).A total of 25 patients with ET(33.3%) suffered from thrombus. The incidence of arterial thrombosis was 26.7%(20/75). The incidence of vein thrombosis was 6.6%(5/75).There was only one person suffered from splenic embolism in patients with PMF.(3)Thromboembolic risk factor analysis:In patients with polythemia vera,the percentage of age≥60 years(P=0.02),.prior thrombosis rate(P=0.018), cardiovascular risk factors rate(P=0.038) and white blood cell counts(P=0.015) were all higher in patients of thrombus than those in patients without thrombosis.In patients with essential thrombocythemia,the percentage of age≥60 years(P=0.02),prior thrombosis rate(P=0.018), the incidence of splenomegaly(P=0.003) and white blood cell counts(P=0.002) were all higher in patients of thrombus than those in patients without thrombosis.Logistic regression analysis showed that prior thrombosis(odds ratio(OR)=5.208,P=0.041),age ≥60 years(OR=3.953,P=0.025)and high white blood cell counts(OR=1.229,P=0.004)were independent risk factors of thrombotic complication in patients with PV.The value of leukocytes in patients with polythemia vera exhibiting the highest sensitivity(67.6%)and specificity(64.9%) by ROC analysis was 12.5×109/L.The splenomegaly(OR=5.208,P=0.041)and high white blood cell counts(OR=1.229,P=0.004)were independent risk factors of thrombotic complication in patients with ET. The value of leukocytes exhibiting the highest sensitivity(67.6%)and specificity(64.9%) was 9.55×109/L.Conclusion:(1)The JAK2V617 F mutation makes different effect on the patients with BCR/ABL negative myeloproliferative neoplasms.In patients with polythemia vera,the level of white blood cell counts and platelet counts,the percentage of males and the incidence of splenomegaly in JAK2V617 F mutated group are significantly higher than those in wild-type JAK2V617 F group.In patients with essential thrombocythemia,the level of platelet counts,the percentage of males and the incidence of splenomegaly in JAK2V617 F mutated group are significantly higher than those in wild-type JAK2V617 F group.While in patients with primary myelofibrosis,these characteristics above are no statistically significant difference.(2)Thromboembolism rate in patients with BCR/ABL negative myeloproliferative neoplasms is high, we should attache great importance to it.(3)The high white blood cell counts,prior thrombosis,and age≥60 years are the independent risk factors of thrombotic events of PV. The value of leukocytes exhibiting the highest sensitivity and specificity is 12.5×109/L.The splenomegaly and high white blood cell counts are independent risk factors of thrombotic complication in patients with ET.The value of leukocytes exhibiting the highest sensitivity and specificity is9.55×109/L.