Serum Ferritin Elevation and Use of Iron Chelation In Chronically Versus Sporadically Transfused Sickle Cell Patients

Red cell transfusions play an integral role in the treatment and prevention of serious complications related to sickle cell disease. It has been shown that in other hemoglobinopathies, such as β-Thalassemia, patients (pts) suffer from iron overload which can result in end organ damage. There is concern that heavily transfused sickle cell pts may also develop iron overload with consequent morbidity and mortality. While pediatric pts routinely receive blood transfusions and iron chelation therapy, adult pts often discontinue chronic transfusion programs and are transfused sporadically. These pts may not receive routine iron chelation therapy.

A retrospective review of our sickle cell database from 1988–2010 which also included those pts who were not routinely followed at the comprehensive sickle cell clinic. Adult pts (>18 yrs of age) with serum ferritin (SF) levels >1000 ng/ml (criteria for iron overload in our institution) were identified and use of iron chelation was reviewed in this population. Clinical characteristics evaluated were age, type of sickle cell disease, frequency of transfusions (chronic vs. sporadic), total units transfused, use and type of chelation, as well as reasons for non-use of chelation therapy.

65/170(38%) pts were identified with SF >1000. The mean age is 33 years (range 19–70). 38/65 (59%) have the SS phenotype, 25/65 (38%) have the Sβ phenotype and 2/65 (3%) have the SC phenotype. The mean SF is 3697 ng/ml (range 1012–14312). Of those pts considered to have iron overload, 28/65 (43%) were treated with iron chelation: 27/65 (42%) received deferasirox and 1/65 (2%) received deferoxamine. Of the untreated pts, 24/37 (65%) had no identifiable reason for lack of chelation therapy, 10/37 (27%) had renal dysfunction, 1/37(3%) had hepatic impairment. 16/65 (25%) were transfused chronically, while 49/65 (75 %) were transfused sporadically. Chronically transfused pts received a mean of 81 units throughout their lifetime, while sporadically transfused pts received 30 units (p=0.01). The mean SF for chronically transfused pts was 5891, while the mean SF for pts transfused sporadically was 2981 (p=0.01). Of pts transfused chronically, 11/16 (69%) were on chelation therapy. Of the pts receiving sporadic transfusions, only 16/49 (33%) were on iron chelation (p= 0.01). In all pts chronically transfused, the reason for non-use of chelation therapy was renal dysfunction. In sporadically transfused pts, 33/49 (51%) had no identifiable reason for lack of chelation therapy.

SF levels are significantly lower in pts who are sporadically transfused, though levels are high. Adult pts receiving sporadic transfusions are not routinely receiving iron chelation therapy despite elevated SF. The need for chelation therapy in both sporadically and chronically transfused pts remains to be determined.

No relevant conflicts of interest to declare.