Subclinical renal abnormalities in young thalassemia major and intermedia patients and its relation to chelation therapy

BackgroundLimited data are available about renal involvement in thalassemia patients. Renal dysfunction in these patients seems to be multifactorial attributed mainly to long standing anemia, chronic hypoxia, iron overload and toxicity of iron chelators.ObjectiveTo assess the frequency of subclinical glomerular and tubular dysfunctions in children and adolescents with β-thalassemia major and intermedia, and to correlate these findings with the degree of iron overload and type of chelation therapy.MethodsThe study included 40 thalassemia major and 20 thalassemia intermedia pediatric patients recruited from the Pediatric hematology clinic, Ain Shams University. Serum sodium, potassium, phosphorous and creatinine, and urinary sodium, potassium, phosphorous, protein/creatinine ratio and urinary β2 microglobulin were measured. Fractional excretion of sodium and potassium was calculated.ResultsThe mean level of serum creatinine in all patients was within the normal range and comparable in both TM and TI groups (0.17 ± 0.06 and 0.18 ± 0.07 mg/dl, respectively, P > 0.05). The mean eGFR was higher than normal range in both TM and TI groups (552.65 ± 231.73 and 472.15 ± 272.99 ml/min, respectively). Mean level of urinary β2 microglobulin was within the normal range (0.13 ± 0.05 and 0.10 ± 0.03 μg/ml) in TM and TI patients, however, it was significantly higher in TM patients (P = 0.009). Urinary β2 microglobulin was positively correlated to both transfusion index and serum ferritin level (P < 0.05). Tubular reabsorption of phosphorus (TRP) was significantly higher among TM patients (P = 0.037). The mean height and height percentile were lower in the poorly chelated group (serum ferritin ⩾2500 ng/ml) than the well chelated group. In addition, the mean serum sodium and urinary protein/creatinine ratio were significantly higher in the poorly chelated group (P < 0.05).ConclusionSubclinical renal affection can start earlier in TM patients compared to TI. Poor chelation is associated with early signs of renal affection. Periodic renal assessment of those patients is mandatory as they may be affected by hidden renal dysfunction.