Serum hepcidin-25 levels predict the progression of renal anemia in patients with non-dialysis chronic kidney disease.

Background: Hepcidin is associated with iron-restricted erythropoiesis. A previous cross-sectional study showed that serum hepcidin-25 levels are negatively associated with the hemoglobin concentration in non-dialysis chronic kidney disease (CKD) patients with sufficient iron stores. This longitudinal study aimed at ascertaining the association between hepcidin-25 levels and the progression of renal anemia.

Methods: We selected 335 non-dialysis CKD patients who showed hemoglobin concentrations >10 g/dL and who were not receiving erythropoiesis-stimulating agent (ESA) therapy, from among the subjects of our previous study, who had been recruited between February and June 2007 in a previous study. The primary outcome was the start of the ESA therapy or hemoglobin concentrations remaining below 10 g/dL for >3 months, by 31 December 2010. The patients were classified into high- and low-ferritin groups depending on their median ferritin levels. The Cox proportional hazard model with restricted cubic spline curve analysis was used to determine the association between hepcidin-25 levels and the outcome for each group.

Results: The hepcidin-25 level was a significant predictor both for the high-ferritin group (P = 0.04, linearity = 0.02) and for the low-ferritin group (P = 0.04, linearity P = 0.02). The spline curve for the high-ferritin group showed that higher hepcidin-25 levels had a high log-relative hazard.

Conclusions: Higher hepcidin-25 levels predict the progression of anemia in non-dialysis CKD patients with sufficient iron stores, indicating the involvement of hepcidin in the progression of anemia in non-dialysis CKD patients.