Intravenous Versus Oral Iron Supplementation for the Treatment of Anemia in CKD: Systematic Review and Meta-analysis

Background: Iron supplementation is essential for the treatment of patients with anemia of chronic kidney disease (CKD). It is not clear which is the best method of iron administration. Study Design: Systematic review and meta-analysis. A search was performed until January 2008 of MEDLINE, Cochrane Central Register of Controlled Trials, conference proceedings in nephrology, and reference lists of included trials. Setting & Population: Patients with CKD (stages III to V). We included dialysis patients and patients with CKD not on dialysis therapy (hereafter referred to as patients with CKD). Selection Criteria for Studies: We included all randomized controlled trials regardless of publication status or language. Intervention: Intravenous (IV) versus oral iron supplementation. Outcomes Measures: Primary outcomes assessed: absolute hemoglobin (Hb) level or change in Hb level from baseline. We also assessed all-cause mortality, erythropoiesis-stimulating agent requirement, adverse events, ferritin level, and need for renal replacement therapy in patients with CKD. Results: 13 trials were identified, 6 including patients with CKD and 7 including dialysis patients. Compared with oral iron, there was a significantly greater Hb level in dialysis patients treated with IV iron (weighted mean difference, 0.83 g/dL; 95% confidence interval, 0.09 to 1.57). Meta-regression showed a positive association between Hb level increase and IV iron dose administered and a negative association with baseline Hb level. For patients with CKD, there was a small but significant difference in Hb level favoring the IV iron group (weighted mean difference, 0. 31 g/dL; 95% confidence interval, 0.09 to 0. 53). Data for all-cause mortality were sparse, and there was no difference in adverse events between the IV- and oral-treated patients. Limitations: There was significant heterogeneity between trials. Follow-up was limited to 2 to 3 months. Conclusions: Our review shows that patients on hemodialysis therapy have better Hb level response when treated with IV iron. For patients with CKD, this effect is small.