Red blood cell transfusion-dependency implies a poor survival in primary myelofibrosis irrespective of IPSS and DIPSS.

Risk stratification in primary myelofibrosis is currently based on two international prognostic scoring systems, neither of which takes into consideration red blood cell transfusion-dependency. In 288 consecutive patients with primary myelofibrosis, red blood cell transfusion-dependency at diagnosis affects survival independently of the International Prognostic Scoring System (P < 0.001). To evaluate the dynamic impact on survival of red blood cell transfusion-dependency, we performed a Cox's regression analysis with transfusion status as time-dependent covariate in 220 regularly followed patients with primary myelofibrosis. Patients who begin red blood cell transfusions anytime (n = 80, 36%) have a significantly worse survival compared to those who continue follow up without transfusions (HR: 7.8, 95%CI: 5.1-11.9; P < 0.001). Adjusting for Dynamic International Prognostic Scoring System in a multivariate analysis, red blood cell transfusion-dependency retained an independent prognostic impact on survival. This study suggests that red blood cell transfusion-dependency should be considered to improve risk stratification of primary myelofibrosis during follow up.