Frequency, pattern, and associations of renal iron accumulation in sickle/β-thalassemia patients

Abstract

We evaluated frequency, pattern, and associations of renal iron accumulation in sickle/β-thalassemia. Thirty-three sickle/β-thalassemia patients (36.5 ± 14.7 years; 13 females), 14 homozygous sickle cell disease (SCD) patients, and 71 thalassemia major (TM) patients, enrolled in the E-MIOT Network, underwent magnetic resonance imaging. Iron overload (IO) was quantified by the T2* technique. Sickle/β-thalassemia patients had a significantly lower frequency of renal IO (T2* < 31 ms) than homozygous SCD patients (9.1% vs. 57.1%; P = 0.001), besides having similar hepatic, cardiac and pancreatic IO. Kidney T2* values were comparable between regularly transfused sickle/β-thalassemia and TM patients but were significantly lower in regularly transfused homozygous SCD patients than in the other two groups. In sickle/β-thalassemia patients, global renal T2* values were not associated with age, gender, splenectomy, and presence of regular transfusions or chelation. No correlation was detected between renal T2* values and serum ferritin levels or iron load in the other organs. Global renal T2* values were not associated with serum creatinine levels but showed a significant inverse correlation with serum lactate dehydrogenase (R = - 0.709; P < 0.0001) and indirect bilirubin (R = - 0.462; P = 0.012). Renal IO is not common in sickle/β-thalassemia patients, with a prevalence significantly lower compared to that of homozygous SCD patients, but with a similar underlying mechanism due to the chronic hemolysis.

Keywords: Iron overload; Kidneys; Magnetic resonance imaging; Sickle/β-thalassemia.