| Research Abstract |
A computer database of refractory anemia patients was created. This included 90 variables of 499 patients. Product limit estimates of median survival from presentation were, 1,305 days in refractory anemia(RA), 497 days in RA with excess of blasts(RAEB), and 1,791 days in RA with ring sideroblasts(RARS), respectively. Leukemic transformation occured within 3,000 days from presentation. Leukemia-free rates after 3,000 days were, 80% in RA, 32% in RAEB, and 9i% in RARS, respectively. Multivariate Cox's proportional hazards model analysis revealed that 6 variables, i.e., RAEB, abnormal granules in granulocyte series, male, mononuclear large megakaryocytes, age older than 50 years, and promyelocytes in peripheral blood<1%, were risk factors for leukemic transformation. For nonleukemic death, risk factors were, metamyelocytes in peripheral blood>=1%, age older than 50 years, lower hemoglobin level, platelet count<100,000/micro liter, mononuclear large megakaryocytes, and abnormal nucleus in granulocyte series. Parametric exponential mixture model revealed that several proportion of patients have negligible risk to be leukemia, and the probability to be leukemia could be estimated by several variables at presentation.
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