Glomerular and tubular functions in children with different forms of beta thalassemia.

BACKGROUND: Although there are many available data about renal involvement in patients with beta thalassemia major (TM), the changes in renal functions of other types, such as thalassemia intermedia (TI) and thalassemia minor (TMin), were reported less. Therefore, we aimed to evaluate renal tubular and glomerular functions in patients with three types of beta thalassemia.

METHODS: This prospective case-control study was conducted on 118 beta-thalassemia patients (49 in TM, 18 in TI and 51 TMin) and 51 healthy controls. Glomerular functions [estimated glomerular filtration rate (GFR), serum cystatin C and urinary protein creatinine ratio] and tubular functions [fractioned sodium excretion (FENa), tubular reabsorption of phosphorus, urinary excretion of uric acid, levels of retinol-binding protein, alpha-1 macroglobulin (alpha-1M), and beta-2 microglobulin, calcium creatinine ratio] were assessed in all patients and controls.

RESULTS: The mean ages of the groups and controls at presentation were similar. Although GFR was similar in all patients and control groups, serum levels of cystatin C in patients with TM and TI were significantly higher compared to TMin and controls. Alpha-1M, FENa, urinary excretion of uric acid, and urine protein/creatinine ratio in TM and TI groups were significantly higher than the others. Mean cystatin C level was also higher in patients with TMin compared the controls. However, there were no significant differences according to all tubular and other glomerular functions between TMin and control groups.

CONCLUSIONS: Although all types of beta thalassemia patients should be closely monitored to prevent further decrease in renal functions, the patients with TI should be considered to have a higher risk of glomerular and tubular deterioration as well as TM.