Oral Iron in Children With Chronic Kidney Disease

Key inclusion criteria: * Age 1-21 years old (muscle strength will be assessed only in children \>3 year old) * Estimated glomerular filtration rate (GFR) \< 90 ml/min/1.73m2 by bedside Schwartz formula \[height (cm) \*0.413 / serum creatinine (mg/dL)\] * Hemoglobin (Hb) more or equal than 9.0 at the previous clinic visit * Hb less than 11.5 g/dL in children younger than 5 years Hb less than 12.0 g/dL in children 5-12 years Hb \<12.5 g/dL in children 12-15 yrs and females \>15 yrs. Hb \<13.5 g/dL in males \>15 years (all at the previous clinic visit) Children with transferrin saturation ≤ 20% AND serum ferritin ≤ 100 ng/mL will be randomized into one of the arms Key exclusion criteria: * Transferrin saturation \<5% * Serum ferritin \< 10 ng/mL * Iron therapy or erythrocyte stimulating agents (erythropoietin) therapy within 3 months prior to randomization * Blood transfusion within 4 months prior to enrollment * Children on hemodialysis * Rapidly deteriorating kidney function or expectation for transplantation or dialysis in less than 3 months * Pregnancy and breast-feeding