SURVIVAL IN MEDICALLY TREATED PATIENTS WITH HOMOZYGOUS BETA-THALASSEMIA

Background. The prognosis of patients with homozygous beta-thalassemia (thalassemia major) has been improved by transfusion and iron-chelati on therapy. We analyzed outcome and prognostic factors among patients receiving transfusions and chelation therapy who had reached the age a t which iron-induced cardiac disease, the most common cause of death, usually occurs. Methods. Using the duration of life without the need f or either inotropic or antiarrhythmic drugs as a measure of survival w ithout cardiac disease, we studied 97 patients born before 1976 who we re treated with regular transfusions and chelation therapy. We used Co x proportional-hazards analysis to assess the effect of prognostic fac tors and life-table analysis to estimate freedom from cardiac disease over time. Results. Of the 97 patients, 59 (61 percent) had no cardiac disease; 36 (37 percent) had cardiac disease, and 18 of them had died . Univariate analysis demonstrated that factors affecting cardiac dise ase-free survival were age at the start of chelation therapy (P<0.001) , the natural log of the serum ferritin concentration before chelation therapy began (P=0.01), the mean ferritin concentration (P<0.001), an d the proportion of ferritin measurements exceeding 2500 ng per millil iter (P<0.001). With stepwise Cox modeling, only the proportion of fer ritin measurements exceeding 2500 ng per milliliter affected cardiac d isease-free survival (P<0.001). Patients in whom less than 33 percent of the serum ferritin values exceeded 2500 ng per milliliter had estim ated rates of survival without cardiac disease of 100 percent after 10 years of chelation therapy and 91 percent after 15 years. Conclusions . The prognosis for survival without cardiac disease is excellent for patients with thalassemia major who receive regular transfusions and w hose serum ferritin concentrations remain below 2500 ng per milliliter with chelation therapy.