Blood 2008 Apr 10;111(7):3383-7. Epub 2008 Jan 10.
Department of Hematology, Fondazione Istituto di ricovero e cura a carattere scientifico Policlinico San Matteo, University of Pavia, Italy.
Post-polycythemia vera myelofibrosis (post-PV MF) is a late evolution of PV. In 647 patients with PV, we found that leukocytosis leukocyte count>(15x10(9)/L) at diagnosis is a risk factor for the evolution of post-PV MF. In a series of 68 patients who developed post-PV MF, median survival was 5.7 years. Hemoglobin level less than 100 g/L (10 g/dL) at diagnosis of post-PV MF was an independent risk factor for survival. The course of post-PV MF, however, is a dynamic process that implies a progressive worsening of clinical parameters. Using a multivariate Cox proportional hazard regression with time-dependent covariates, we found that a dynamic score based on hemoglobin level less than 100 g/L (10 g/dL), platelet count less than 100x10(9)/L, and leukocyte count more than 30x10(9)/L is useful to predict survival at any time from diagnosis of post-PV MF. The resulting hazard ratio of the score was 4.2 (95% CI: 2.4-7.7; P<.001), meaning a 4.2-fold worsening of survival for each risk factor acquired during follow up. In conclusion, leukocytosis at diagnosis of PV is a risk factor for evolution in post-PV MF. A dynamic score based on hemoglobin level, and platelet and leukocyte count predicts survival at any time from diagnosis of post-PV MF.