Incidence and risk factors for myelofibrotic transformation among 272 Chinese patients with JAK2-mutated polycythemia vera.

Post-polycythemia vera myelofibrosis (post-PV MF) is a critical hematologic evolution of polycythemia vera (PV). The main purpose of the present study was to identify the possible risk factors for the occurrence and prognosis of post-PV MF in Chinese patients with PV. A cohort of 272 Chinese PV patients with JAK2(V617F) or exon12 mutation was retrospectively analyzed. Of the 272 patients with PV, 63 developed post-PV MF. Platelet count >550 × 10(9) /L and splenomegaly were identified as independent risk factors for post-PV MF. The median duration of survival for post-PV MF patients was 8 years. Anemia and age >65 years at diagnosis of post-PV MF were identified as significant predictors for the poor prognosis of post-PV MF. In conclusion, platelet counts and splenomegaly were significant predictors for the transformation to post-PV MF, while anemia (hemoglobin levels <100 g/L) and age>65 years were significant predictors for poor prognosis of post-PV MF in Chinese PV patients with JAK2(V617F) or exon12 mutation.