Severity of iron overload in patients with sickle cell disease receiving chronic red blood cell transfusion therapy

Abstract

Chronic transfusion therapy is being used more frequently to prevent and treat the complications of sickle cell disease. Previous studies have shown that the iron overload that results from such therapy in other patient populations is associated with significant morbidity and mortality. In this study we examined the extent of iron overload as well as the presence of liver injury and the predictive value of ferritin in estimating iron overload in children with sickle cell disease who receive chronic red blood cell transfusions. A poor correlation was observed between serum ferritin and the quantitative iron on liver biopsy (mean 13.68 +/- 6.64 mg/g dry weight; R = 0.350, P =.142). Quantitative iron was highly correlated with the months of transfusion (R = 0.795, P <.001), but serum ferritin at biopsy did not correlate with months of transfusion (R = 0.308, P =.200). Sixteen patients had abnormal biopsies showing mild to moderate changes on evaluation of inflammation or fibrosis. Liver iron was correlated with fibrosis score (R = 0.50, P =.042). No complications were associated with the liver biopsy. Our data suggest that, in patients with sickle cell disease, ferritin is a poor marker for accurately assessing iron overload and should not be used to direct long-term chelation therapy. Despite high levels of liver iron, the associated liver injury was not severe.