Impact of Splenectomy and Chelating Agents on Serum Cystatin C Levels in Egyptian Children With Beta-Thalassemia

The outlook for patients with thalassemia has improved in recent decades with the use of modern transfusion practice and iron chelation, but patients continue to be at high risk for iron overload and its toxicities. Cystatin C (CysC) has been suggested as a sensitive marker of glomerular filtration rate providing an early indication of renal impairment, possibly superior to serum creatinine. This study was conducted to observe changes in cystatin C serum concentration in β-thalassemia patients treated with chelating therapy and to determine whether splenectomy could change serum cystatin C concentration. This study recruited 40 pediatrics patients with transfusion-dependent β-thalassemia from Hematology Clinic of Pediatric Hospital, Faculty of Medicine, Cairo University. A control group of 31 ageand sex-matched Egyptian children was also included. Results: 72.5% of thalassemia patients had cystatin C values greater than the upper limit of normal (ULN, 0.99 mg/L) whereas 2.5% of the patients had increased serum creatinine (ULN, 1.4 mg/dL). Patients on subcutaneous infusion chelation were 10 (25%). They had significant higher serum levels of urea, creatinine, CysC and duration of chelation (P = .016, P = 0.007, P = 0.001, P = 0.000 respectively) than patients on oral chelation therapy. No significant difference was found between patient's subgroups of oral chelation therapy regarding disease onset, disease duration, blood transfusion rate, splenectomy duration, serum levels of urea, creatinine and CysC (P > 0.05) for all. Patients with splenectomy were 22 (55%), with significant higher serum levels of urea, creatinine, CysC and duration of chelation (P = 028, P = 0.003, P = 0.000, P = 0.001 respectively). In thalassemia patients, CysC showed significant positive correlation with serum levels of ALT, AST, urea, creatinine, ,systolic BP,BMI ,duration of chelation and age (r = 0. .380, P = 0.016; r = 0. .432, P = 0.005) , r = .746, P = .000 ;r = .696, P = .000 ; r =.530, P = .000; r = .356, P = .024 ; r = .515, P = .001 and r = .543, P = .000 respectively). Conclusion: These findings suggest that slight changes of cystatin C serum levels in β-thalassemia major patients during chelating therapy or after splenectomy may not reflect renal impairment and, therefore, measurements of this biomarker should be interpreted with caution.