Low levels of serum ferritin lead to adequate hemoglobin levels and good survival in hemodialysis patients

Potential hazards of recent trends in liberal iron use for renal anemia

A randomized controlled trial,the Proactive IV Iron Therapy in Haemodialysis Patients (PIVOTAL), has recently shown that a high-dose (‘proactive’) intravenous iron regimen was superior to a low-dose (‘reactive’) regimen for hemodialysis patient outcomes and overall safety. However, even in the low-dose group, a substantial amount of iron was administered to maintain serum ferritin >200 ng/mL. This type of comparison may have strongly affected the safety results. Iron has two opposite effects on erythropoiesis: it activates erythroid differentiation directly by supplying iron but inhibits it indirectly by stimulating hepcidin and enhancing oxidative stress. Hepcidin plays an essential role not only in iron homeostasis and the anemia of chronic kidney disease, but also in its complications such as atherosclerosis and infection. Its main stimulation by iron—and to a lesser degree by inflammation—should urge clinicians to avoid prescribing excessive amounts of iron. Furthermore, as serum ferritin is closely correlated with serum hepcidin and iron storage, it would seem preferable to rely mainly on serum ferritin to adjust iron administration, defining an upper limit for risk reduction. Based on our estimations, the optimal range of serum ferritin is ∼50–150 ng/mL, which is precisely within the boundaries of iron management in Japan. Considering the contrasting ranges of target ferritin levels between end-stage renal disease patients in Japan and the rest of the world, the optimal range proposed by us will probably be considered as unacceptable by nephrologists abroad. Only well-balanced, randomized controlled trials with both erythropoiesis-stimulating agents and iron will allow us to settle this controversy.

Systemic inflammation modulates the ability of serum ferritin to predict all-cause and cardiovascular mortality in peritoneal dialysis patients

Background

This study aimed to ascertain whether the correlation of high serum ferritin with mortality is affected by systemic inflammation and to investigate the optimal serum ferritin level for predicting death when inflammation is considered in peritoneal dialysis (PD) patients.

Methods

We classified 221 patients into four groups according to serum ferritin concentration (100 μg/L) and high-sensitivity CRP (hs-CRP) level (3 mg/L), and followed them regularly from the date of catheterization to Dec 31, 2016, at Sun Yat-Sen Memorial Hospital, China. Clinical and biochemical data were collected at baseline, and clinical outcomes such as all-cause and cardiovascular mortality were assessed.

Results

During a median follow-up of 35 months (3 ~ 109 months), 50 (22.6%) deaths occurred. Cardiovascular disease (46.0%) was the most common cause of death, followed by infection (10.0%). The Kaplan–Meier survival analysis and log-rank test revealed significantly worse survival accumulation among PD patients with higher serum ferritin (≥100 μg/L) under elevated hsCRP levels (> 3 mg/L) (P = 0.022). A multivariate Cox regression analysis revealed that an increased serum ferritin level was independently associated with a higher risk of all-cause and cardiovascular mortality in PD patients (HR = 3.114, P = 0.021; and HR = 9.382, P = 0.032) with hsCRP above 3 mg/L after adjusting for relevant confounding factors.

Conclusion

Higher serum ferritin levels were associated with an increased risk of all-cause and cardiovascular mortality in patients undergoing PD only in the presence of elevated hsCRP levels. The correlation of serum ferritin with poor outcome should take into consideration systemic inflammation.

Serum Erythroferrone Levels Associate with Mortality and Cardiovascular Events in Hemodialysis and in CKD Patients: A Two Cohorts Study

Erythroferrone (ERFE) is a hepcidin inhibitor whose synthesis is stimulated by erythropoietin, which increases iron absorption and mobilization. We studied the association between serum ERFE and mortality and non-fatal cardiovascular (CV) events in a cohort of 1123 hemodialysis patients and in a cohort of 745 stage 1–5 chronic kidney disease (CKD) patients. Erythroferrone was measured by a validated enzyme-linked immunosorbent assay (ELISA). In the hemodialysis cohort, serum ERFE associated directly with erythropoiesis stimulating agents (ESA) dose (p < 0.001) and inversely with serum iron and ferritin (p < 0.001). Erythroferrone associated with the combined outcome in an analysis adjusting for traditional risk factors, factors peculiar to end-stage kidney disease, serum ferritin, inflammation, and nutritional status (HR, hazard ratio, (5 ng/mL increase: 1.04, 95% confidence interval, CI: 1.01–1.08, p = 0.005). Furthermore, treatment with ESA modified the relationship between ERFE and the combined end-point in adjusted analyses (p for the effect modification = 0.018). Similarly, in CKD patients there was a linear increase in the risk for the same outcome in adjusted analyses (HR (2 ng/mL increase): 1.04, 95% CI: 1.0–1.07, p = 0.015). Serum ERFE is associated with mortality and CV events in CKD and in HD patients, and treatment by ESA amplifies the risk for this combined end-point in HD patients.

High serum hepcidin is associated with the occurrence of anemia in anti-myeloperoxidase antibody-associated vasculitis with normal kidney function: a cross-sectional study

The etiology of anemia in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) has not been elucidated. In this cross-sectional study, we tried to investigate the relationship between serum hepcidin and anemia in myeloperoxidase (MPO)-ANCA-AAV. Data of 64 newly diagnosed AAV patients who did not have kidney dysfunction or hemorrhage were analyzed. Serum hepcidin was measured with enzyme linked immunosorbent assay. Twenty-three of 64 patients had anemia. Compared with patients without anemia, patients with anemia had higher Birmingham vasculitis activity score [10 (3, 23) vs. 5 (3, 17), p = 0.020], lower levels of serum iron (5.83 ± 1.63 vs. 9.76 ± 1.54, p < 0.001) and higher levels of ferrtin [358.00 (59.85, 1314.10) vs. 151.05 (43.00, 645.30), p = 0.006]. All 64 patients had increased levels of serum hepcidin compared with normal controls, while patients with anemia had higher serum hepcidin than patients without anemia (85.30 ± 16.92 ng/mL vs. 53.48 ± 13.32 ng/mL, p < 0.001). In the multivariable analysis, the level of hemoglobin correlated with the levels of serum iron (r = 0.344, p = 0.026) and hepcidin (r = - 0.353, p = 0.022). Low level of serum iron was related to high level of serum hepcidin (r = - 0.472, p = 0.001). Immunosuppressive treatment induced rapid decrease of hepcidin and increase of serum iron on the 1st month, while the recovery of hemoglobin was relatively slow. This study indicated that in MPO-AAV without kidney dysfunction or hemorrhage, the existence of anemia is associated with high level of hepcidin which induces low serum iron and the abnormality of iron utilization.

Impact of Inflammation on Ferritin, Hepcidin and the Management of Iron Deficiency Anemia in Chronic Kidney Disease

Iron deficiency anemia (IDA) is a major problem in chronic kidney disease (CKD), causing increased mortality. Ferritin stores iron, representing iron status. Hepcidin binds to ferroportin, thereby inhibiting iron absorption/efflux. Inflammation in CKD increases ferritin and hepcidin independent of iron status, which reduce iron availability. While intravenous iron therapy (IIT) is superior to oral iron therapy (OIT) in CKD patients with inflammation, OIT is as effective as IIT in those without. Inflammation reduces predictive values of ferritin and hepcidin for iron status and responsiveness to iron therapy. Upper limit of ferritin to predict iron overload is higher in CKD patients with inflammation than in those without. However, magnetic resonance imaging studies show lower cutoff levels of serum ferritin to predict iron overload in dialysis patients with apparent inflammation than upper limit of ferritin proposed by international guidelines. Compared to CKD patients with inflammation, optimal ferritin levels for IDA are lower in those without, requiring reduced iron dose and leading to decreased mortality. The management of IDA should differ between CKD patients with and without inflammation and include minimization of inflammation. Further studies are needed to determine the impact of inflammation on ferritin, hepcidin and therapeutic strategy for IDA in CKD.

Burden of Anemia in Chronic Kidney Disease Patients in Japan: A Literature Review

Anemia is a common complication for patients with chronic kidney disease (CKD) and is associated with cardiovascular comorbidities and reduced quality of life. The incidence of anemia increases as kidney function declines and affects approximately 32% of Japanese patients with stage 3-5 CKD. This review examined the current literature on anemia in CKD patients in Japan to provide an overview of the burden of anemia in CKD. Medline, Embase, and Igaku Chuo Zasshi databases were searched to identify relevant manuscripts and abstracts published from 2004 onward. The population included CKD patients with anemia, and the outcomes of interest were epidemiology, economic, humanistic, and treatment patterns. Observational studies, database analysis, and economic evaluation studies were included in the analysis. A total of 1151 references were identified, and 50 were eligible for final review. Economic burden was reported in most studies (n = 37) followed by treatment patterns (n = 26), and epidemiological (n = 25) and humanistic (n = 1) burdens. Prevalence of anemia varied largely (0-95%) based on the different definitions of anemia, and increased with CKD severity. Higher mortality was associated with erythropoiesis-stimulating agent (ESA) resistance and lower hemoglobin levels among patients treated with ESA. Drug dosage was the most reported economic burden (n = 33), followed by medical, and non-medical outcomes. Costs associated with anemia were considerable and depended on dialysis status and ESA treatment. Only one study reported data on quality of life, suggesting that further investigation on the humanistic burden of anemia in CKD is needed.

When should iron supplementation in dialysis patients be avoided, minimized or withdrawn?

Parenteral iron is used to restore the body's iron pool before and during erythropoiesis‐stimulating agent (ESA) therapy; together these agents form the backbone of anemia management in end‐stage renal disease (ESRD) patients undergoing hemodialysis. ESRD patients receiving chronic intravenous iron products, which exceed their blood loss are exposed to an increased risk of positive iron balance. Measurement of the liver iron concentration (LIC) reflects total body iron stores in patients with secondary hemosiderosis and genetic hemochromatosis. Recent studies of LIC in hemodialysis patients, measured by quantitative MRI and magnetic susceptometry, have demonstrated a high risk of iron overload in dialysis patients treated with IV iron products at doses advocated by current anemia management guidelines for dialysis patients. Liver iron overload causes increased production of hepcidin and elevated plasma levels, which can activate macrophages of atherosclerotic plaques. This mechanism may explain the results of 3 long‐term epidemiological studies which showed the association of excessive IV iron doses with increased risk of cardiovascular morbidity and mortality among hemodialysis patients. A more physiological approach of iron therapy in ESRD is needed. Peritoneal dialysis patients, hemodialysis patients infected with hepatitis C virus, and hemodialysis patients with ferritin above 1000 μg/L without a concomitant inflammatory state, all require specific and cautious iron management. Two recent studies have shown that most hemodialysis patients will benefit from lower maintenance IV iron dosages; their results are applicable to American hemodialysis patients. Novel pharmacometric and economic approaches to iron therapy and anemia management are emerging which are designed to lessen the potential side effects of excessive IV iron while maintaining hemoglobin stability without an increase in ESA dosing.

Optimal Serum Ferritin Levels for Iron Deficiency Anemia during Oral Iron Therapy (OIT) in Japanese Hemodialysis Patients with Minor Inflammation and Benefit of Intravenous Iron Therapy for OIT-Nonresponders

Background: We determined optimal serum ferritin for oral iron therapy (OIT) in hemodialysis (HD) patients with iron deficiency anemia (IDA)/minor inflammation, and benefit of intravenous iron therapy (IIT) for OIT-nonresponders. Methods: Inclusion criteria were IDA (Hb <120 g/L, serum ferritin <227.4 pmol/L). Exclusion criteria were inflammation (C-reactive protein (CRP) ≥ 5 mg/L), bleeding, or cancer. IIT was withheld >3 months before the study. ΔHb ≥ 20 g/L above baseline or maintaining target Hb (tHB; 120-130 g/L) was considered responsive. Fifty-one patients received OIT (ferrous fumarate, 50 mg/day) for 3 months; this continued in OIT-responders but was switched to IIT (saccharated ferric oxide, 40 mg/week) in OIT-nonresponders for 4 months. All received continuous erythropoietin receptor activator (CERA). Hb, ferritin, hepcidin-25, and CERA dose were measured. Results: Demographics before OIT were similar between OIT-responders and OIT-nonresponders except low Hb and high triglycerides in OIT-nonresponders. Thirty-nine were OIT-responders with reduced CERA dose. Hb rose with a peak at 5 months. Ferritin and hepcidin-25 continuously increased. Hb positively correlated with ferritin in OIT-responders (r = 0.913, p = 0.03) till 5 months after OIT. The correlation equation estimated optimal ferritin of 30-40 ng/mL using tHb (120-130 g/L). Seven OIT-nonresponders were IIT-responders. Conclusions: Optimal serum ferritin for OIT is 67.4-89.9 pmol/L in HD patients with IDA/minor inflammation. IIT may be a second line of treatment for OIT-nonreponders.

Iatrogenic iron overload and its potential consequences in patients on hemodialysis

Iron overload was considered rare in hemodialysis patients until recently, but its clinical frequency is now increasingly recognized. The liver is the main site of iron storage and the liver iron concentration (LIC) is closely correlated with total iron stores in patients with secondary hemosiderosis and genetic hemochromatosis. Magnetic resonance imaging (MRI) is now the gold standard method for estimating and monitoring LIC. Studies of LIC in hemodialysis patients by magnetic susceptometry thirteen years ago and recently by quantitative MRI have demonstrated a relation between the risk of iron overload and the use of intravenous (IV) iron products prescribed at doses determined by the iron biomarker cutoffs contained in current anemia management guidelines. These findings have challenged the validity of both iron biomarker cutoffs and current clinical guidelines, especially with respect to recommended IV iron doses. Moreover, three recent long-term observational studies suggested that excessive IV iron doses might be associated with an increased risk of cardiovascular events and death in hemodialysis patients. It has been hypothesized that iatrogenic iron overload in the era of erythropoiesis-stimulating agents might silently increase complications in dialysis patients without creating obvious, clinical signs and symptoms. High hepcidin-25 levels were recently linked to fatal and nonfatal cardiovascular events in dialysis patients. It has been postulated that the main pathophysiological pathway leading to these events might involve the pleiotropic master hormone hepcidin, which regulates iron metabolism, leading to activation of macrophages in atherosclerotic plaques and then to clinical cardiovascular events. Thus, the potential iron overload toxicity linked to chronic administration of IV iron therapy is now becoming one of the most controversial topics in the management of anemia in hemodialysis patients.

Impact of iatrogenic iron overload on the course of hepatitis C in the dialysis population: A plea for caution

About 2.5% of the world population, corresponding to about 177 million individuals, are infected by hepatitis C virus (HCV), a small, single-stranded RNA virus. The prevalence of HCV infection among dialysis patients in Japan, Europe, and North America during the 2012 to 2015 period was found to be 8.7% in the DOPPS study. Nosocomial HCV spread in hemodialysis facilities still occurs. Increased hepatic tissue iron has been shown to play a deleterious role in the course of hepatitis C, favor development of fibrosis and cirrhosis and possibly increase the risk of liver cancer in the general population. Regular loss of blood in the hemodialysis circuit, in routine blood sampling for laboratory tests (for uremia monitoring), and in gut due to uremic enteropathy, invariably results in iron deficiency for which patients are commonly treated with intravenous (IV) iron preparations. Data on the effects of IV iron in hemodialysis patients with hepatitis C are limited (2 studies) and strongly suggest that parenteral iron may contribute to hepatocellular injury. Iatrogenic iron overload is extremely prevalent among hemodialysis population worldwide. Iron overload and toxicity has emerged as one of the most controversial topic in the management of anemia in dialysis patients. Given the known impact of iron in promoting growth and virulence of HCV and the associated liver disease, it is necessary to use iron therapy cautiously and closely monitor plasma markers of iron metabolism and liver iron stores non-invasively by means of MRI to avoid iron overload in this vulnerable population.

Iatrogenic Iron Overload in Dialysis Patients at the Beginning of the 21st Century

Iron overload used to be considered rare in hemodialysis patients but its clinical frequency is now increasingly realized. The liver is the main site of iron storage and the liver iron concentration (LIC) is closely correlated with total iron stores in patients with secondary hemosideroses and genetic hemochromatosis. Magnetic resonance imaging is now the gold standard method for LIC estimation and monitoring in non-renal patients. Studies of LIC in hemodialysis patients by quantitative magnetic resonance imaging and magnetic susceptometry have demonstrated a strong relation between the risk of iron overload and the use of intravenous (IV) iron products prescribed at doses determined by the iron biomarker cutoffs contained in current anemia management guidelines. These findings have challenged the validity of both iron biomarker cutoffs and current clinical guidelines, especially with respect to recommended IV iron doses. Three long-term observational studies have recently suggested that excessive IV iron doses may be associated with an increased risk of cardiovascular events and death in hemodialysis patients. We postulate that iatrogenic iron overload in the era of erythropoiesis-stimulating agents may silently increase complications in dialysis patients without creating frank clinical signs and symptoms. High hepcidin-25 levels were recently linked to fatal and nonfatal cardiovascular events in dialysis patients. It is therefore tempting to postulate that the main pathophysiological pathway leading to these events may involve the pleiotropic master hormone hepcidin (synergized by fibroblast growth factor 23), which regulates iron metabolism. Oxidative stress as a result of IV iron infusions and iron overload, by releasing labile non-transferrin-bound iron, might represent a ‘second hit’ on the vascular bed. Finally, iron deposition in the myocardium of patients with severe iron overload might also play a role in the pathogenesis of sudden death in some patients.