Serum hepcidin-25 levels and anemia in non-dialysis chronic kidney disease patients: a cross-sectional study.

BACKGROUND Hepcidin is a central regulator of iron homeostasis. Increased hepcidin concentrations could cause iron-restricted erythropoiesis in chronic kidney disease (CKD)-associated anemia. This cross-sectional observational study was conducted to evaluate the association between hepcidin and CKD-associated anemia in non-dialysis CKD patients. METHODS A total of 505 non-dialysis CKD patients not treated with parenteral iron were recruited, and serum hepcidin-25 levels were measured by liquid chromatography tandem mass spectrometry. Multiple linear regression analysis was used to examine the relationship between hepcidin and glomerular filtration rate (GFR) and the relationship between hemoglobin concentration and predictors including the hepcidin level. RESULTS The median hepcidin level among the 505 CKD patients was 15.4 ng/mL (interquartile range, 5.5-33.6 ng/mL). Although hepcidin level significantly increased according to the CKD stage, multivariate analysis did not reveal an association of GFR with the hepcidin level. Hepcidin level was a significant predictor of hemoglobin concentration after the adjustment for confounders, and a significant interaction between hepcidin and ferritin was found. After stratifying at the median ferritin level, 91 ng/mL, we found a negative association between hepcidin level and hemoglobin in the high-ferritin group. A trend toward a negative association between hepcidin level and mean corpuscular volume was observed in the high-ferritin group. CONCLUSIONS Serum hepcidin-25 levels were negatively associated with hemoglobin concentrations in non-dialysis CKD patients with sufficient iron stores. We found that ferritin modified the association between hepcidin level and hemoglobin concentration. In addition, our results confirmed that the serum hepcidin level is not associated with GFR.