Oral iron monotherapy has limited efficacy in the treatment of anemia in patients with nondialysis-dependent chronic kidney disease (ND-CKD), findings from a new study suggest.
Iain Macdougall, MD, of King’s College Hospital, Denmark Hill, London, and colleagues performed a post-hoc analysis of FIND-CKD, a 52-week, randomized, multicenter trial of iron therapy in 308 iron-deficient, anemic ND-CKD patients with a mean baseline hemoglobin (Hb) level of 10.4 g/dL. The analysis excluded patients with active infection, C-reactive protein levels above 20 mg/L, recent therapy with an erythropoiesis-stimulating agent (ESA), or oral iron intolerance. The patients received 200 mg elemental iron daily, with alternative treatment permitted only after 8 weeks. The investigators defined erythropoietic response as a 1 g/dL or greater increase in Hb from baseline, before initiation of alternative anemia therapy, such as ESA, transfusion, or intravenous iron.
Four weeks after starting oral iron therapy, just 21.6% patients had an erythropoietic response, according to published in Clinical Nephrology (2017;88:301-310). Of the nonresponders at week 4, 48.8% of patients showed a 1 g/dL increase in Hb at some point by week 52. At visits at weeks 8, 12, 24, and 52, 11.1%, 19.9%, 25.9%, and 28.7%, respectively, showed response. More than half of nonresponders at week 4 never had a response.
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“Oral iron supplementation is widely used in anemic ND-CKD patients with iron deficiency; however, results from this large, prospective study highlight the limited efficacy of this approach, with only 21.6% of patients having responded four weeks after continuous treatment with oral iron,” Dr Macdougall and his colleagues wrote.
The best time for nonresponders to switch from oral iron to alternative therapy is still unclear. By 52 weeks, 27.9% had received intravenous iron, transfusion, or an erythropoiesis-stimulating agent. “Earlier consideration of alternative therapy could improve anemia management in this population,” the authors noted.
Patients with worse anemia (lower baseline levels of Hb, ferritin, and transferrin saturation) were more likely to respond to oral iron therapy. Medications such as antacids, H2 blockers, proton pump inhibitors, phosphate binders, and tetracycline antibiotics are known to interfere with oral iron absorption. But medications and adherence were similar between early responders and nonresponders. The study lacked a placebo group, which precludes some other useful analyses.
Funding was provided by Vifor Pharma, makers of intravenous iron products.
Reference
Macdougall IC, Bock AH, Carrera F, et al. Erythropoietic response to oral iron in patients with nondialysis-dependent chronic kidney disease in the FIND-CKD trial. Clin Nephrol. 2017 Dec;88(12):301-310. doi: 10.5414/CN109198.
