Cumulative incidence of acquisition of risk factors during follow-up, estimated with death as a competing risk in patients with primary myelofibrosis. The cumulative incidence of each risk factor has been calculated considering only patients who did not have the risk factor at diagnosis. (A) Time to anemia (hemoglobin < 100 g/L [10 g/dL]). (B) Time to leukocytosis (WBC count > 25 × 10⁹/L). (C) Time to blastosis (peripheral blood blasts ≥ 1%). (D) Time to constitutional symptoms.