Hepcidin and hemoglobin content parameters in the diagnosis of iron deficiency in rheumatoid arthritis patients with anemia

Objective To explore the utility of the novel iron indices hepcidin, reticulocyte hemoglobin content (Ret‐Hgb), and erythrocyte (red blood cell) hemoglobin content (RBC‐Hgb) for detection of iron deficiency in rheumatoid arthritis (RA) patients with anemia and active inflammation and to compare these indices with conventional parameters of iron deficiency. Methods Blood samples from 106 outpatients with RA were analyzed in a cross‐sectional exploratory study. Forty patients were classified as having either iron deficiency anemia (IDA), anemia of chronic disease (ACD), their combination (IDA/ACD), or “other anemia” based on biochemical parameters for inflammation and iron deficiency. The ability of serum and urine hepcidin, Ret‐Hgb, and RBC‐Hgb measurement to discriminate among these states was evaluated. Results Hepcidin content in serum from patients in the IDA group as well as that from patients in the combined IDA/ACD group differed significantly from that in serum from patients in the ACD group. This difference was also observed with hepcidin in urine, Ret‐Hgb, and RBC‐Hgb, although with less significance. The area under the receiver operating characteristic curve for serum hepcidin was 0.88 for the comparison of IDA/ACD patients with ACD patients and 0.92 for the comparison of the combined IDA group and IDA/ACD group to all other patients with anemia. Hepcidin at