Renal Function and the Oxidative Status Among Children with Thalassemia Major and Healthy Controls: A Cross-sectional Study

Background: Renal dysfunction is an underestimated complication of thalassemia major.

Objectives: The aim of this study is to compare the glomerular and tubular functions in children with β- Thalassemia major (β- TM) with healthy controls and assess the oxidative stress caused by high ferritin levels.

Design And Setting: This prospective cross-sectional study was conducted in tertiary care hospital.

Methods: Complete blood count (CBC), calcium (Ca), urea, creatinine (Cr), serum cystatin C before transfusion and urinary calcium (uCa), creatinine (uCr), protein (UPr) levels were analyzed in fresh samples. Beta-2-microglobulin (uβ2-MG), N- acetylglucosaminidase (uNAG), retinol binding protein (uRBP), malonedialdehyde (uMDA) secretion and creatinine levels were analyzed. Serum total antioxidant capacity (sTAC) and total oxidant capacity (sTOC) were measured with colorimetric micro-ELISA method. Last four serum ferritin values were recorded and the mean value was used for statistical analyzes.

Results: Data from 47 patients and 32 controls were analyzed. The urinary RBP/Cr, Ca/Cr and Protein/Cr, were significantly higher in β-TM group. A statistically insignificant increase in urinary β2MG/Cr, uNAG/Cr, MDA/Cr was also found in the TM group. Proteinuria was present in 46 % (n: 22) and hypercalciuria in 34 % (n: 16) of the patients with β- TM. Serum total antioxidant capacity and total oxidant status (TOS) levels were significantly elevated in the patient group. Serum ferritin was significantly correlated with proteinuria, cystatin C levels, urinary Protein/Cr and uRBP/Cr.

Conclusion: Asymptomatic renal dysfunction is prevalent in β- TM patients that necessitate regular screening. Urinary RBP may be useful for early diagnosis.