Prognostic features of paroxysmal nocturnal hemoglobinuria in Japan

A survey on the survival of a total of 160 patients with paroxysmal nocturnal hemoglobinuria (PNH) was conducted by questionnaires to hematologists at the 86 major hospitals in Japan. Ten, 20 and 30 year-survival rates from the day of diagnosis was 71%, 57.5% and 57.5%, respectively. The survival curves by sex showed no statistical difference between males and females. The cause of death in 56 patients with PNH was investigated. Twenty cases, representing 38.5% of 52 patients excluding 4 cases of unknown cause, died of hemorrhage. Death from thrombosis occurred only in 3 cases. The incidence of hemorrhage and thrombosis as a cause of death in Japanese patients was clearly different from that in the United States and England. Various causes other than hemorrhage and thrombosis were disclosed. Patients died 4.5 years (median) from diagnosis and at a mean age of 50.4 years. Hypoplastic bone marrow was found histologically in 40.4% of 52 patients by biopsy. The findings of peripheral blood and aspirated bone marrow were nearly consistent with those of hypoplasia. A higher incidence of hemorrhagic death in Japanese patients might be related to thrombocytopenia by hypoplastic bone marrow. On initial diagnosis, 41.2% had aplastic anemia-PNH syndrome. Prevention against complications in PNH with special reference to blood transfusions are discussed.