Early Predictors of Renal Dysfunction in Egyptian Patients with β-Thalassemia Major and Intermedia

BACKGROUND: Better survival of thalassemia patients allowed previously unrecognized renal complications to emerge. OBJECTIVES: Assess prevalence and early predictors of renal dysfunction in young β-thalassemia major (β-TM) and intermedia (β-TI) patients. SUBJECTS: 66 β-TM (group I), 26 β-TI (group II) Egyptian patients and 40 healthy controls. METHODS: Clinical assessment and laboratory data including kidney and liver function tests, such as serum ferritin, serum bicarbonate, plasma osmolality and urinary total proteins, microalbuminuria (MAU), N-acetyl-β-D-glucosaminidase (NAG), retinol binding protein (RBP), α-1 microglobulin, bicarbonate, osmolality, creatinine clearance (CrCl), % fractional excretion of bicarbonate (% FE-HCO3). RESULTS: The prevalent renal abnormality was proteinuria (71%), followed by increased urinary level of RBP (69.4%), NAG (58.1%), α-1 microglobulin (54.8%) and microalbuminuria (29%) and also decreased urinary osmolality (58.1%). CrCl was a better assessment of renal function and significantly lowered in thalassemia patients. Tubular dysfunctions were more significant in splenectomized β-TM patients who showed more elevation of NAG and α-1 microglobulin and lower urinary osmolality. NAG, RBP and α-1 microglobulin were negatively correlated with CrCl and positively correlated with serum ferritin and urinary total protein. Z-score analysis for identifying patients with renal dysfunction proved superiority of urine total protein and RBP. Comparative statistics of different frequencies revealed significant difference between the urinary total protein and both MAU and % FE-HCO3. CONCLUSION: Asymptomatic renal dysfunctions are prevalent in young β-TM and β-TI patients that necessitate regular screening. Urinary total protein and RBP may be cost-effective for early detection.