Cardiovascular Events and Intensity of Treatment in Polycythemia Vera

SUMMARY: The significance of maintaining a hematocrit less than 45% to prevent cardiovascular events, was evaluated in this randomized clinical study. Patients with JAK2-positive polycythemia vera (n=365) treated with phlebotomy, hydroxyurea, or both were randomized to receive either a more intensive treatment to maintain a target hematocrit of less than 45% (low-hematocrit group, n=182) or less intensive treatment to a target hematocrit of 45 to 50% (high-hematocrit group, n= 183). The primary end point was the time until death from cardiovascular events or major thrombotic episodes. The secondary end points included cardiovascular events, cardiovascular hospitalizations, incidence of cancer, progression to myelofibrosis, myelodysplasia or leukemia and hemorrhage. At a median follow-up of 31 months, the primary end point was recorded in 5 of 182 patients (2.7%) in the low-hematocrit group and 18 of 183 patients (9.8%) in the high-hematocrit group ( P=0.007). There were no significant differences in the secondary end points. The authors concluded that maintaining a lower hematocrit can lower the risk of cardiovascular death and major thrombosis. Marchioli R, Finazzi G, Specchia G, et al. N Engl J Med 2013; 368:22-33