Oral ferric citrate hydrate (FCH) is effective for iron deficiencies in hemodialysis patients; however, how iron balance in the body affects iron absorption in the intestinal tract remains unclear. This prospective observational study (Riona-Oral Iron Absorption Trial, R-OIAT, UMIN 000031406) was conducted at 42 hemodialysis centers in Japan, wherein 268 hemodialysis patients without inflammation were enrolled and treated with a fixed amount of FCH for 6 months. We assessed the predictive value of hepcidin-25 for iron absorption and iron shift between ferritin (FTN) and red blood cells (RBCs) following FCH therapy. Serum iron changes at 2 h (ΔFe2h) after FCH ingestion were evaluated as iron absorption. The primary outcome was the quantitative delineation of iron variables with respect to ΔFe2h, and the secondary outcome was the description of the predictors of the body’s iron balance. Generalized estimating equations (GEEs) were used to identify the determinants of iron absorption during each phase of FCH treatment. ΔFe2h increased when hepcidin-25 and TSAT decreased (−0.459, −0.643 to −0.276, p = 0.000; −0.648, −1.099 to −0.197, p = 0.005, respectively) in GEEs. FTN increased when RBCs decreased (−1.392, −1.749 to −1.035, p = 0.000) and hepcidin-25 increased (0.297, 0.239 to 0.355, p = 0.000). Limiting erythropoiesis to maintain hemoglobin levels induces RBC reduction in hemodialysis patients, resulting in increased hepcidin-25 and FTN levels. Hepcidin-25 production may prompt an iron shift from RBC iron to FTN iron, inhibiting iron absorption even with continued FCH intake.

Background: Although the angiotensin receptor-neprilysin inhibitor sacubitril-valsartan has demonstrated a valuable effect on cardiac function in patients with heart failure with a reduced ejection fraction, the effect of this agent in hemodialysis patients is not well known. Case presentation: Sacubitril-valsartan was administered to two anuric hemodialysis patients, an 81-year-old woman and a 79-year-old man, after aortic valve replacement for aortic stenosis. Following sacubitril-valsartan administration, the two patients’ N-terminal pro-brain natriuretic peptide levels decreased from 110,373 to 47,742 and 22,723 to 7692 pg/mL within one month, respectively, and were sustained within the lower levels thereafter. Although the patients’ left ventricular ejection fractions were 40.0% and 28.4%, respectively, these values did not change at seven and four months after sacubitril-valsartan administration (41.0% and 30.0%, respectively) but increased gradually to 56.6% and 54.9% at 11 and 13 months, respectively, and were sustained at the same levels thereafter. Conclusions: Long-term sacubitril-valsartan administration can improve cardiac function in hemodialysis patients with a reduced ejection fraction.