A 12-Week, Double-Blind, Placebo-Controlled Trial of Ferric Citrate for the Treatment of Iron Deficiency Anemia and Reduction of Serum Phosphate in Patients With CKD Stages 3-5

BACKGROUND: Iron deficiency anemia and serum phosphate levels > 4.0mg/dL are relatively common in chronic kidney disease stages 3 to 5 and are associated with higher risks of progressive loss of kidney function, cardiovascular events, and mortality. STUDY DESIGN: Double-blind, placebo-controlled, randomized trial. SETTING transferrin saturation TSAT≤ 30%, serum ferritin ≤ 300 ng/mL), and serum phosphate levels ≥ 4.0 to 6.0mg/dL. Use of intravenous iron or erythropoiesis-stimulating agents was prohibited. INTERVENTION: Randomization to treatment for 12 weeks with ferric citrate coordination complex (ferric citrate) or placebo. OUTCOMES between-group P<0.001 for each). Ferric citrate increased hemoglobin levels (from 10.5 ± 0.8 to 11.0 ± 1.0 g/dL; P<0.001 vs placebo), reduced urinary phosphate excretion 39% (P<0.001 vs placebo), and reduced serum intact FGF-23 levels from a median of 159 (IQR, 102-289) to 105 (IQR, 65-187) pg/mL (P=0.02 vs placebo). The incidence and severity of adverse effects were similar between treatment arms. LIMITATIONS: The study is limited by relatively small sample size and short duration and by having biochemical rather than clinical outcomes. CONCLUSIONS: Short-term use of ferric citrate repletes iron stores, increases hemoglobin levels, and reduces levels of serum phosphate, urinary phosphate excretion, and FGF-23 in patients with chronic kidney disease stages 3 to 5.