Validation of serum ferritin values by magnetic susceptometry in predicting iron overload in dialysis patients

Anemia of Chronic Kidney Disease-A Narrative Review of Its Pathophysiology, Diagnosis, and Management

Anemia is one of the most common chronic kidney disease (CKD) complications. It negatively affects patients' quality of life and clinical outcomes. The pathophysiology of anemia in CKD involves the interplay of various factors such as erythropoietin (EPO) deficiency, iron dysregulation, chronic inflammation, bone marrow dysfunction, and nutritional deficiencies. Despite recent advances in understanding this condition, anemia still remains a serious clinical challenge in population of patients with CKD. Several guidelines have been published with the aim to systematize the diagnostic approach and treatment of anemia; however, due to emerging data, many recommendations vary between publications. Recent studies indicate a potential of novel biomarkers to evaluate anemia and related conditions such as iron deficiency, which is often present in CKD patients. Our article aims to summarize the pathophysiology of anemia in CKD, as well as the diagnosis and management of this condition, including novel therapeutic approaches such as hypoxia-inducible factor-prolyl hydroxylase inhibitors (HIF-PHI). Understanding these complex subjects is crucial for a targeted approach to diagnose and treat patients with anemia in CKD effectively.

Biochemical markers of iron status and iron accumulation in peritoneal dialysis patients treated with ferric citrate

BACKGROUND

Hyperphosphataemia is a common complication of kidney disease. Current dialysis techniques do not provide enough phosphorus clearance, hence the need to use phosphorus binders. Treatment options include calcium carbonate, calcium acetate, lanthanum carbonate, sevelamer hydrochloride and iron-based binders. Patients receiving peritoneal dialysis (PD) with sustained elevated ferritin levels exceeding 800 ng/mL are at a higher risk of death. We identify PD patients treated with iron-based binders and compare ferritin and risk of iron accumulation to patients treated with non-iron-based binders.

METHODS

All records of patients receiving PD at Emory dialysis centres until 30 October 2021 were reviewed for phosphorus binders. Basic demographics and laboratory data were time-referenced to the days on treatment with a particular binder. Patients were followed until discontinuation of the phosphorus binder, death, transplant, transfer to another dialysis provider or censoring at 36 months after medication was started.

RESULTS

Compared to calcium acetate and sevelamer, ferric citrate utilisation in PD patients resulted in a sustained increase in ferritin. The proportion of patients with a ferritin equal to or greater than 800 ng/dL and transferrin saturation greater than 40% increased over time in patients treated with ferric citrate and was higher during the second and third year of follow-up compared to baseline values and to patients treated with calcium acetate or sevelamer. Two patients (7%) treated with ferric citrate developed clinically significant haemosiderosis.

CONCLUSIONS

Use of ferric citrated in PD resulted in significant iron accumulation as judged by ferritin levels.

Iron overload in hemodialysis patients: Comparison of serum iron parameters with T2* MRI sequence

PURPOSE

To evaluate correlation between serum iron parameters and liver T2* value in hemodialysis patients with iron overload due to parenteral iron therapy.

MATERIALS AND METHODS

We evaluated 30 hemodialysis patients using a multiecho T2*-weighted MRI sequence. Age, sex, duration of dialysis, iron and erythropoietin doses taken in the past year, and serum iron parameters were recorded. Liver T2* values were averaged from three distinct liver regions. A T2* value of 33 ± 7 ms is considered normal. Declines below 24, 21, and 14 ms signify iron overload grades 1, 2, and 3, respectively.

RESULTS

There was no statistically significant difference comparing the measurements of 3 different ROIs (p > 0.05). A total of 23 patients (76.6%) had iron overload. Serum ferritin levels of patients with iron overload were significantly higher than those without iron overload (687.25 [186.5-1489] ng/mL vs. 371.25 [127.5-542.5] ng/mL, p = 0.008). No linear correlation was observed between age, dialysis duration, serum iron metrics, medication doses, and T2* values. Likewise, no significant differences were found among patients based on iron overload status or its grades concerning these parameters.

CONCLUSION

While standard serum markers might overlook iron overload, elevated ferritin levels are promising. MRI reliably detects iron overload in patients receiving parenteral iron.

Relationship between bone marrow iron load and liver iron concentration in dialysis-associated haemosiderosis

BACKGROUND

Iron overload due to the excessive use of parenteral iron in haemodialysis is now an increasingly recognised clinical issue. Before erythropoiesis-stimulating agents (ESA) were introduced, a specific feature of patients treated by dialysis and having iron overload was that iron levels in the bone marrow were paradoxically low in most of them, despite severe hepatosplenic siderosis. Whether or not this paradox persists in the actual ESA era was unknown until recently, when an autopsy study in 21 patients treated by haemodialysis revealed similarities between liver and bone marrow iron content. The aim of this study was to further explore these recent findings in a cohort of alive patients on dialysis and to analyse the determinants of iron bone marrow.

METHODS

Liver iron concentration (LIC) and vertebral T2∗ (a surrogate marker of bone marrow iron) were analysed retrospectively in 152 alive patients on dialysis (38.8% female) of whom 47.4% had iron overload by quantitative magnetic resonance imaging (MRI).

FINDINGS

Vertebral T2∗ differed significantly between patients classified according to liver iron content at MRI: those with mild or moderate and severe liver iron overload had increased vertebral iron content at R2∗ relaxometry MRI (mild: vertebral T2∗ = 9.9 ms (4-24.8); moderate and severe: vertebral T2∗ = 8.5 ms (4.9-22.8)) when compared to patients with normal LIC (vertebral T2∗ = 13.2 ms (6.6-30.5) (p < 0.0001 Kruskal-Wallis test)).

INTERPRETATION

The paradoxical discrepancy between bone marrow and liver iron-storage compartments observed in the pre-ESA era has disappeared today, as shown by a recent autopsy study and the present study in a cohort of alive patients treated by dialysis.

FUNDING

None.

Association of Estimated Total Body Iron with All-Cause Mortality in Japanese Hemodialysis Patients: The Miyazaki Dialysis Cohort Study

Iron deficiency/excess may be associated with worse prognosis in patients undergoing hemodialysis. This study ascertained the association of the estimated total body iron (TBI) with mortality in patients receiving hemodialysis. Multicenter clinical data collected in the Miyazaki Dialysis Cohort Study from 943 patients receiving hemodialysis were analyzed after stratification into tertile categories by baseline TBI-estimated as the heme iron plus iron storage from ferritin levels. The primary outcome was a 5-year all-cause mortality; hazard ratios of the TBI-all-cause mortality association were estimated using Cox models adjusted for potential confounders, including clinical characteristics, laboratory, and drug data, wherein patients with high TBI were the reference category. The receiver operating characteristic (ROC) curve analyses of TBI, serum ferritin levels, and transferrin saturation were performed to predict all-cause mortality; a total of 232 patients died during the follow-up. The low TBI group (<1.6 g) had significantly higher hazard ratios of mortality than the high TBI group (≥2.0 g). As ROC curve analyses showed, TBI predicted mortality more accurately than either levels of serum ferritin or transferrin saturation. Lower TBI increases the mortality risk of Japanese hemodialysis patients, and further studies should examine whether iron supplementation therapy that avoids low TBI improves prognosis.

Hepatic and cardiac iron overload quantified by magnetic resonance imaging in patients on hemodialysis: A systematic review and meta-analysis

INTRODUCTION

Few studies have reported hepatic and cardiac iron overload in patients with end-stage renal disease (ESRD), and the current evidence regarding the prevalence is still scarce.

AIM

This review aims to estimate the prevalence of hepatic and/or cardiac iron overload quantified by magnetic resonance imaging (MRI) in patients with ESRD who receive hemodialysis (HD), peritoneal dialysis (PD), or have undergone a kidney transplant.

METHODS

A systematic review with meta-analysis was conducted and reported in line with PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) guidelines. MEDLINE and Embase bibliographic databases were searched using a comprehensive list of controlled vocabulary and keywords to identify relevant studies. All studies reporting the prevalence of hepatic and/or cardiac iron overload quantified by MRI in ESRD patients were considered. The Newcastle-Ottawa scale was used to assess the methodological quality of included studies. To investigate the heterogeneity between studies, random-effect meta-analyses for proportions were used.

RESULTS

The review comprised seven studies that included 339 patients. Using meta-analysis, the pooled prevalence of severe and mild to moderate hepatic iron overload quantified by MRI was 0.23 [95% CI: 0.08-0.43] and 0.52 [95% CI: 0.47-0.57], respectively. Only three studies included cardiac iron quantification, and none reported iron overload.

CONCLUSIONS

This review has revealed a high prevalence of severe hepatic iron overload in patients with ESRD treated by HD. Further studies with a larger sample size are needed to determine the impact of iron overload on vital organs in patients with ESRD and guide future research in this understudied field. Proper use of iron chelation and continuous monitoring will help in the early detection of unsolicited complications; however, the low renal clearance of most iron chelators limits the options for treating iron excess in patients with ESRD.

Iron Overload in Chronic Kidney Disease: Less Ferritin, More T2*MRI

To date, there is no consensus on the most reliable marker of iron status in patients with chronic kidney disease (CKD). Serum ferritin is used routinely, although it may be a misleading marker for iron overload. The success of T2^* MRI in monitoring iron overload in patients with hemoglobinopathies can be beneficial to monitoring patients with CKD.

Post-mortem liver and bone marrow iron quantification in haemodialysis patients: A prospective cohort study

Background

Magnetic resonance liver scans indicate that iron overload is common in haemodialysis (HD) patients. However, histological evidence is scarce.

Methods

Liver biopsy and bone marrow aspirate were obtained in the first 24h post mortem from 21 adult HD patients. Biochemical liver iron content (LIC) was quantified by electrothermal atomization atomic absorption spectrophotometry. Tissue iron deposition was graded in the liver and bone marrow using Scheuer and Gale's criteria, respectively.

Findings

Median LIC was 42.5 (22.9-69.7) μmol/g and the majority (n=11; 57%) had mild to moderate liver iron overload (LIC >36 μmol/g). Scheuer grade was 2 (1-3) and 13 (62%) of liver biopsies had increased (> 1) iron deposition. In the bone marrow, median Gale's grade was 3 (3-4) and 9 (45%) patients had increased (>3) iron content.

Contrary to old autopsy studies, done in the pre-erythropoiesis-stimulating agents (ESAs) era, both liver and bone marrow were iron replete and showed a positive correlation (r=0.71, p<0.001).

Ferritin proved to have a good diagnostic accuracy for liver iron overload (0.87 95% CI 0.71-1.00) with an optimal cut-off value of 422 ng/ml. Haemoglobin was negatively associated with both LIC (r= -0.46, p=0.04) and iron content in the bone marrow (p=0.04). Patients with increased LIC had higher resistance to ESAs (p=0.02), yet no association with previous IV iron therapy.

Interpretation

In the majority of HD patients there was iron accumulation in both the liver and bone marrow that associated with anaemia severity and resistance to ESAs, suggesting a blocking mechanism of iron's utilization.

Funding

None.

The Superiority of T2*MRI Over Serum Ferritin in the Evaluation of Secondary Iron Overload in a Chronic Kidney Disease Patient: A Case Report

Secondary iron overload is increasingly encountered in chronic kidney disease (CKD) patients because of the frequent use of parenteral iron products, especially in hemodialysis patients. Serum ferritin has been commonly used to monitor iron overload in these patients; however, other conditions can be associated with the high serum ferritin, like infections and inflammatory conditions. Currently, T2*MRI of the heart and liver is the preferred investigation for evaluating liver iron concentration (LIC) and cardiac iron concentration, which reflect the state of iron overload. Few studies observe a positive correlation between serum iron and LIC in CKD patients and postulate that serum ferritin exceeding 290 mcg/L should indicate significant iron overload and necessitates further MRI evaluation. However, here, we present a patient with a history of ESRD for which she underwent renal transplantation twice referred to our clinic due to persistent elevation in serum ferritin level (>1000 mcg/L) for several years. T2*MRI of the heart and liver revealed the absence of iron overload. Our objective of this case is to demonstrate the accuracy of T2*MRI over serum ferritin in evaluating iron overload and questioning the positive correlation between serum ferritin and LIC in CKD patients.

Intravenous iron in heart failure and chronic kidney disease

Intravenous iron therapy is increasingly being used worldwide to treat anemia in chronic kidney disease and more recently iron deficiency in heart failure. Promising results were obtained in randomized clinical trials in the latter, showing symptomatic and functional capacity improvement with intravenous iron therapy. Meanwhile, confirmation of clinical benefit in hard-endpoints such as mortality and hospitalization is expected in large clinical trials that are already taking place. In chronic kidney disease, concern about iron overload is being substituted by claims of direct cardiovascular benefit of iron supplementation, as suggested by preliminary studies in heart failure. We discuss the pitfalls of present studies and gaps in knowledge, stressing the known differences between iron metabolism in heart and renal failure. Systemic and cellular iron handling and the role of hepcidin are reviewed, as well as the role of iron in atherosclerosis, especially in view of its relevance to patients undergoing dialysis. We summarize the evidence available concerning iron overload, availability and toxicity in CKD, that should be taken into account before embracing aggressive intravenous iron supplementation.

Roxadustat in treating anemia in dialysis patients (ROAD): protocol and rationale of a multicenter prospective observational cohort study

BACKGROUND

Roxadustat has been shown effective in treating patients with anemia due to chronic kidney disease. However, its long-term effect on clinical outcomes and socioeconomic burden and safety remains unclear.

METHODS/DESIGN

This is a multicenter, prospective, longitudinal observational cohort study assessing if Roxadustat improves prognosis in dialysis patients. Primary outcomes will be major adverse cardiovascular events (MACE), defined as composites of cardiovascular death, myocardial infarction, cerebral infarction, hospitalization because of heart failure; all-cause mortality, and annual economic costs in two years. The data will be collected via Research electronic data capture (REDCap) based database as well as software-based dialysis registry of Sichuan province. The primary outcomes for the ROAD study participants will be compared with those in the dialysis registry cohort. Data at baseline and study follow up will also be compared to assess the association between Roxadustat and long-term clinical outcomes.

DISCUSSION

The main objective of this study is to the assess long-term association of Roxadustat on MACE, all-cause mortality, socio-economic burden, safety in dialysis patients, which will provide guidance for designing further large randomized controlled trials to investigate this clinic question.

STUDY REGISTRATION

The study has been registered in Chinese Clinical Trials Registry (ROAD, ROxadustat in treating Anemia in Dialysis patients, registration number ChiCTR1900025765) and provincial observational cohort database (Renal disEAse observational CoHort database, REACH, ChiCTR1900024926), registered 07 September 2019, http://www.chictr.org.cn .

Intravenous iron in heart failure and chronic kidney disease

Intravenous iron therapy is increasingly being used worldwide to treat anemia in chronic kidney disease and more recently iron deficiency in heart failure. Promising results were obtained in randomized clinical trials in the latter, showing symptomatic and functional capacity improvement with intravenous iron therapy. Meanwhile, confirmation of clinical benefit in hard-endpoints such as mortality and hospitalization is expected in large clinical trials that are already taking place. In chronic kidney disease, concern about iron overload is being substituted by claims of direct cardiovascular benefit of iron supplementation, as suggested by preliminary studies in heart failure. We discuss the pitfalls of present studies and gaps in knowledge, stressing the known differences between iron metabolism in heart and renal failure. Systemic and cellular iron handling and the role of hepcidin are reviewed, as well as the role of iron in atherosclerosis, especially in view of its relevance to patients undergoing dialysis. We summarize the evidence available concerning iron overload, availability and toxicity in CKD, that should be taken into account before embracing aggressive intravenous iron supplementation.

Iatrogenic Iron Overload in a Patient With Chronic Kidney Disease: Is There a Correlation Between Serum Ferritin and Liver Iron Concentration Determined by MRI T2*?

Secondary iron overload in patients with chronic kidney disease (CKD) due to iatrogenic iron replacement is an emerging medical challenge. There are limited options to manage secondary iron overload in patients with CKD as most iron chelators are contraindicated due to low creatinine clearance. In addition to that, accuracy of serum ferritin in monitoring is questionable since it is affected by different variables including inflammation and liver disease. Moreover, correlation of serum ferritin with liver iron concentration (LIC) and heart iron concentration is not well studied in CKD patients. There is no established cut-off value in the current guidelines, and this warrants further investigation with more accurate methods.

There are few studies that evaluated the relationship between serum ferritin and LIC determined by different MRI protocols. Limited data in the literature concluded that a positive correlation exists between serum ferritin and LIC determined by MRI T2* and that serum ferritin more than 290 mcg/L is equivalent to severe iron overload on MRI T2*. However, we had a different observation of a patient with CKD on a prolonged course of iron replacement who was monitored with serum ferritin, and despite having a serum ferritin level of more than 1,000 mcg/L, LIC determined by MRI T2* was 5.3 mg/g of liver dry tissue, which is equivalent to mild iron overload. 

This observation opens the door for further studies to examine the correlation between serum ferritin and LIC determined by MRI and to establish a safe cut-off value of serum ferritin so that further investigation would be indicated in patients with CKD.

Particular aspects of gastroenterological disorders in chronic kidney disease and end-stage renal disease patients: a clinically focused review

Besides renal disease, gastrointestinal (GI) disorders are frequently reported in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD). Related gastrointestinal symptoms tend to increase as the renal disease progresses. Also, in patients with ESRD, the modality of dialysis is related to particular forms of GI disorders.The kidney can interact with the digestive organs through functional endogenous systems such as the 'kidney-colon axis' and the 'kidney-liver axis'. Digestive diseases are one of the visible manifestations of the disturbance between hemostatic, hemodynamic and immunological balance in such patients.No clear management guidelines currently exist for many of the gastrointestinal problems that accompany renal failure. This review aims to describe the particular aspects of GI diseases present in CKD/ESRD. We focus our discussion in the specificities of epidemiology, diagnosis, and prognosis of such disorders between the different segments of the digestive system.

Histological Scores Validate the Accuracy of Hepatic Iron Load Measured by Signal Intensity Ratio and R2* Relaxometry MRI in Dialysis Patients

Almost all haemodialysis patients are treated with parenteral iron to compensate for blood loss and to allow the full therapeutic effect of erythropoiesis-stimulating agents. Iron overload is an increasingly recognised clinical situation diagnosed by quantitative magnetic resonance imaging (MRI). MRI methods have not been fully validated in dialysis patients. We compared Deugnier’s and Turlin’s histological scoring of iron overload and Scheuer’s classification (with Perls’ stain) with three quantitative MRI methods for measuring liver iron concentration (LIC)—signal intensity ratio (SIR), R2* relaxometry, and R2* multi-peak spectral modelling (Iterative Decomposition of water and fat with Echo Asymmetry and Least-squares estimation (IDEAL-IQ^®)) relaxometry—in 16 haemodialysis patients in whom a liver biopsy was formally indicated for medical follow-up. LIC MRI with these three different methods was highly correlated with Deugnier’s and Turlin’s histological scoring (SIR: r = 0.8329, p = 0.0002; R2* relaxometry: r = −0.9099, p < 0.0001; R2* relaxometry (IDEAL-IQ^®): r = −0.872, p = 0.0018). Scheuer’s classification was also significantly correlated with these three MRI techniques. The positive likelihood ratio for the diagnosis of abnormal LIC by Deugnier’s histological scoring was > 62 for the three MRI methods. This study supports the accuracy of quantitative MRI methods for the non-invasive diagnosis and follow-up of iron overload in haemodialysis patients.

Labile plasma iron levels in chronic hemodialysis patients treated by intravenous iron supplementation

The increased usage of intravenous iron in hemodialysis patients during recent years has led to increasing concern over the potential development of iron overload. Current methods for detecting iron overload, transferrin saturation, and serum ferritin are neither sensitive nor specific. Labile plasma iron (LPI) represents a component of nontransferrin-bound iron and may be a more accurate indicator of impending iron overload. We studied whether LPI measured can serve as an early indicator of impending iron overload and mortality in hemodialysis patients. Chronic hemodialysis patients from two medical centers in Israel and Poland who received intravenous iron were included. Baseline clinical and laboratory parameters were recorded. LPI was measured before and 48 hours after a single IV administration. Correlation of positive LPI with laboratory parameters and 2-year mortality was evaluated. One hundred and one hemodialysis patients were included in the study. LPI became positive post-administration in 18 (17.8%) patients. Ferritin levels >526 ng/mL and monthly iron doses >250 mg were associated with positive LPI after intravenous iron. At a 2-year follow-up, higher mortality was observed in the positive LPI group (61.1% compared to 25.3%, P ≤ .05), although this effect was not statistically significant after multivariate adjustment. A substantial number of hemodialysis patients have positive LPI after intravenous iron administration. LPI positively correlates with laboratory parameters that are currently in routine clinical use for detecting iron overload and with higher intravenous iron dose. Further studies should be conducted to establish the clinical implications of LPI monitoring in hemodialysis patients.

On the characteristic and stability of iron diet supplements

The iron diet supplements: AproFER 1000 and AproTHEM were subjected to various chemical, microbial and magnetic analysis. The microbial analysis revealed no presence of pathogenic bacteria in the studied products. No significant changes in iron content or forms (bivalent/trivalent) were observed in EPR analysis of supplements stored at different conditions for a long period of time. The chemical and magnetic analysis showed that both AproFER 1000 and AproTHEM contain a high concentration of bivalent iron so they can be used as an iron diet supplements.

What do we learn about the “Anemia Module” of the French language Peritoneal Dialysis ? Interest and Results

Background: Anemia is commonly observed in patients with chronic kidney disease (CKD) as soon as the glomerular filtration rate falls below than 30 ml/min. CKD patients frequently have iron deficiency. The use of both erythropoiesis-stimulating agents (ESA) and iron therapy is the backbone of anemia management in CKD. For this reason, an adequate iron supply is mandatory to achieve the optimal therapeutic benefit of erythropoiesis stimulating agents (ESAs). Many groups agree that anemia in peritoneal dialysis (PD) patients is less severe than in hemodialysis (HD) patients and that there are important differences in treatment practices for anemia between PD and HD patients. Methods: Analysis of the Anemia module of the French Language Peritoneal Dialysis Registry (RDPLF) register from the database set up in 2005 with a study of the period 2010-2017. Results: Data from 568 patients who participated in the Anemia module were analysed during the 2010-2017 follow-up period. Their median age were 71 years, 42% were female, median dialysis vintage was 13 months, 40,5% of patients had diabetes mellitus, 74% of patients were treated with ESA, 23% were on oral iron and only 11% have received intravenous iron. In terms of biological assessment, the average hemoglobin level was close to 12 g/dl and median CRP was close to 5 mg/l. For the iron balance, ferritin reached an average level of 270 µg/l in 2013 and stabilized in 2017 at 200 µg/l. The transferrin saturation coefficient always fluctuated between 23 % and 25 % from year 2010 to year 2017. Conclusion: The results of the Anemia module of RDPLF register appear to be in line with the target values of the ERA-EDTA latest European guideline on anemia (ERBP 2013) and show the low use of intravenous iron in PD (usually as second line therapy).

Risk of iron overload with chronic indiscriminate use of intravenous iron products in ESRD and IBD populations

The routine use of recombinant erythropoiesis-stimulating agents (ESA) over the past three decades has enabled the partial correction of anaemia in most patients with end-stage renal disease (ESRD). Since ESA use frequently leads to iron deficiency, almost all ESA-treated haemodialysis patients worldwide receive intravenous iron (IV) to ensure sufficient available iron during ESA therapy. Patients with inflammatory bowel disease (IBD) are also often treated with IV iron preparations, as anaemia is common in IBD. Over the past few years, liver magnetic resonance imaging (MRI) has become the gold standard method for non-invasive diagnosis and follow-up of iron overload diseases. Studies using MRI to quantify liver iron concentration in ESRD have shown a link between high infused iron dose and risk of haemosiderosis in dialysis patients. In September 2017, the Pharmacovigilance Committee (PRAC) of the European Medicines Agency (EMA) considered convergent publications over the last few years on iatrogenic haemosiderosis in dialysis patients and requested that companies holding marketing authorization for iron products should investigate the risk of iron overload, particularly in patients with end-stage renal disease on dialysis and, by analogy, patients with IBD. We present a narrative review of data supporting the views and decision of the EMA, and then give our expert opinion on this controversial field of anaemia therapeutics.

Liver Iron Load Influences Hepatic Fat Fraction in End-Stage Renal Disease Patients on Dialysis: A Proof of Concept Study

Background

Nonalcoholic fatty liver disease (NAFLD) is a spectrum of diseases including steatosis, nonalcoholic steatohepatitis (NASH), cirrhosis, and end-stage liver failure. Hepatic iron accumulation has been linked to hepatic fibrosis severity in NASH and NAFLD. Iron overload induced by parenteral (IV) iron therapy is a potential clinical problem in dialysis patients. We analyzed the hypothetical triggering and aggravating role of iron on NAFLD in patients on dialysis.

Methods

Liver iron concentration (LIC) and hepatic proton density fat fraction (PDFF) were analyzed prospectively in 68 dialysis patients by magnetic resonance imaging (MRI). Follow up of LIC and PDFF was performed in 17 dialysis patients during iron therapy.

Findings

PDFF differed significantly among dialysis patients classified according to LIC: patients with moderate or severe iron overload had increased fat fraction (PDFF: 7.9% (0.5–14.8%)) when compared to those with normal LIC (PDFF: 5% (0.27–11%)) or mild iron overload (PDFF: 5% (0.30–11.6%); P = 0.0049). PDFF correlated with LIC, and ferritin and body mass index. In seven patients monitored during IV iron therapy, LIC and PDFF increased concomitantly (PDFF: initial 2.5%, final 8%, P = 0.0156; LIC: initial 20 μmol/g, final 160 μmol/g: P = 0.0156), whereas in ten patients with iron overload, PDFF decreased after IV iron withdrawal or major dose reduction (initial: 8%, final: 4%; P = 0.0098) in parallel with LIC (initial: 195 μmol/g, final: 45 μmol/g; P = 0.002).

Interpretation

Liver iron load influences hepatic fat fraction in dialysis patients. Iron overload induced by iron therapy may aggravate or trigger NAFLD in dialysis patients.

Trial registration number (ISRCTN)

80100088.

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.

Iron parameters in patients with end-stage renal disease receiving lanthanum carbonate or other non-iron-based phosphate binders: Results from a phase 3, randomized open-label study

OBJECTIVES

The recent availability of iron-based phosphate binders has raised some concerns about iron overload in patients with end-stage renal disease. This study evaluated iron parameters in patients with end-stage renal disease receiving lanthanum carbonate or other non-iron-based phosphate binders.

METHODS

This analysis used 2-year follow-up data from an open-label, multicentre, randomized, active-controlled, parallel-group, phase 3 trial of lanthanum carbonate (SPD405-307). After a washout period, if patients' serum phosphate levels exceeded 5.9 mg/dL, they were randomized 1:1 to receive lanthanum carbonate (375-3000 mg/day) or non-iron-based standard therapy during a 6-week dose titration period. Patients achieving control of serum phosphate levels (⩽5.9 mg/dL) received maintenance therapy with lanthanum carbonate or standard therapy for up to 24 months.

RESULTS

No clinically relevant changes in mean (standard deviation) iron parameters between the treatment groups (lanthanum carbonate, n = 682; standard therapy, n = 677) from baseline to month 24/final visit were observed: iron (µg/dL), -1.1 (41.8) versus 1.0 (38.7); ferritin (ng/mL), 208.4 (445.1) versus 262.4 (505.5); transferrin saturation (%), 2.8 (18.0) versus 2.8 (17.3); and haemoglobin (g/dL), 0.4 (1.9) versus 0.3 (1.7), respectively (all, p > 0.1). There were no clinically relevant changes in the percentage of patients receiving any anti-anaemic preparation in either treatment group (pre- vs post-randomization: lanthanum carbonate, 94.9% vs 97.8%; standard therapy, 95.1% vs 98.8%, respectively). This is in contrast to the study by Lewis and colleagues, which found significant increases in ferritin and transferrin saturation levels in patients receiving ferric citrate versus active control (calcium acetate and/or sevelamer carbonate) after 52 weeks of therapy. Although serum ferritin and transferrin saturation are the recommended iron indices by the Kidney Disease Outcome Quality Initiative, they are indirect indicators of iron status. Longer-term studies are required to understand fully the potential risks associated with iron overload.

CONCLUSION

No evidence of iron accumulation was found in patients with end-stage renal disease receiving lanthanum carbonate or other non-iron-based binders.

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.

Renal association clinical practice guideline on Anaemia of Chronic Kidney Disease

Anaemia is a commonly diagnosed complication among patients suffering with chronic kidney disease. If left untreated, it may affect patient quality of life. There are several causes for anaemia in this patient population. As the kidney function deteriorates, together with medications and dietary restrictions, patients may develop iron deficiency, resulting in reduction of iron supply to the bone marrow (which is the body organ responsible for the production of different blood elements). Chronic kidney disease patients may not be able to utilise their own body's iron stores effectively and hence, many patients, particularly those receiving haemodialysis, may require additional iron treatment, usually provided by infusion.With further weakening of kidney function, patients with chronic kidney disease may need additional treatment with a substance called erythropoietin which drives the bone marrow to produce its own blood. This substance, which is naturally produced by the kidneys, becomes relatively deficient in patients with chronic kidney disease. Any patients will eventually require treatment with erythropoietin or similar products that are given by injection.Over the last few years, several iron and erythropoietin products have been licensed for treating anaemia in chronic kidney disease patients. In addition, several publications discussed the benefits of each treatment and possible risks associated with long term treatment. The current guidelines provide advice to health care professionals on how to screen chronic kidney disease patients for anaemia, which patients to investigate for other causes of anaemia, when and how to treat patients with different medications, how to ensure safe prescribing of treatment and how to diagnose and manage complications associated with anaemia and the drugs used for its treatment.

Interpretation of the Kidney Disease: Improving Global Outcomes guidelines for iron therapy: commentary and emerging evidence

The ‘Kidney Disease: Improving Global Outcomes’ (KDIGO) Clinical Practice Guideline for Anaemia in Chronic Kidney Disease includes detailed recommendations for the use of iron therapy in a variety of clinical circumstances. However, the evidence base regarding the use of iron therapy in patients with chronic kidney disease was relatively incomplete at the time the guideline was developed. As a result, there has been significant debate as to the appropriate use of iron therapy in this population. In this article, the KDIGO guidelines are discussed in the context of recently published commentary pieces and additional research to provide a richer context in which to interpret and understand the guidelines.

Intravenous iron therapy in patients with chronic kidney disease: recent evidence and future directions

Current recommendations for the use of intravenous iron therapy in the management of anaemia in patients with chronic kidney disease (CKD) are based on limited clinical evidence. Since the publication of the Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline for Anaemia in Chronic Kidney Disease in 2012, a number of randomized clinical trials [notably, the Ferinject Assessment in Patients with Iron Deficiency Anaemia (FIND-CKD) and Randomized Trial to Evaluate IV and Oral Iron in Chronic Kidney Disease (REVOKE) trials] and observational studies have been completed, and a further large clinical trial—Proactive IV Iron Therapy in Dialysis Patients (PIVOTAL)—is currently underway. In this article, the implications of the findings from these recent studies are discussed and the critical evidence gaps that remain to be addressed are highlighted.

Practical considerations for iron therapy in the management of anaemia in patients with chronic kidney disease

Clinical practice guidelines provide both local and global recommendations for the use of iron therapy in the management of anaemia in patients with chronic kidney disease. However, physicians must interpret and adapt these guidelines to meet the specific needs of their individual patients. The recommendations must also be considered in the context of findings from more recently published clinical trials and observational studies.

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.

Diagnosing and preventing iron overload

Absolute or functional iron (Fe) deficiency is an important determinant of anemia in hemodialysis patients and parenteral Fe is routinely used to treat this condition in conjunction with erythropoiesis stimulating agents. While restoration of hemoglobin toward the target range is a good outcome of Fe replacement, it is well known that Fe overload and toxicity may be adverse consequences of this therapy. Dialysis clinical practice guidelines recommend tailoring Fe therapy based on transferrin saturation and serum ferritin levels. Unfortunately, serum Fe markers may not accurately reflect the amount of Fe in the body, because factors such as infections, inflammation, or malignancy can alter serum ferritin levels. Some recent trials in dialysis patients receiving high intravenous Fe doses have shown increased cardiovascular morbidity and mortality and studies using magnetic resonance imaging (MRI) in this population have shown excessive tissue liver iron content (LIC) suggesting Fe overload. While LIC measured by MRI correlates well with LIC quantitated by liver biopsy, it only represents a surrogate marker for total body Fe and its clinical relevance in dialysis patients in terms of mortality and morbidity remains to be demonstrated. Nevertheless, these recent findings challenge the use of current serum Fe markers recommended by clinical guidelines to guide safe Fe therapy in dialysis patients. While not yet established for the routine screening of dialysis patients for Fe overload, MRI should be considered in patients who have received a high cumulative dose of intravenous Fe, or have long cumulative dialysis vintage. Further studies are needed to assess how MRI will alter management.

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.

Signal-intensity-ratio MRI accurately estimates hepatic iron load in hemodialysis patients

Background

Iron overload, diagnosed by means of magnetic resonance imaging (MRI), is an increasingly recognized disorder in hemodialysis patients. Specific MRI protocols have been shown to provide a reliable estimation of tissue iron content in non-renal patient populations but have not been validated in dialysis patients. Such validation studies require liver biopsy for histological comparison, but this invasive and risky procedure raises ethical concerns, especially regarding frail patients with end-stage renal disease.

Materials and methods

We compared in a pilot study Scheuer’s histological classification and Deugnier and Turlin’s histological classification of iron overload (Perls staining) with signal-intensity-ratio MRI values obtained with the Rennes University algorithm in 11 hemodialysis patients in whom liver biopsy was formally indicated for their medical follow-up.

Results

For Scheuer’s histological classification, the Wilcoxon non-parametric matched-pairs test showed no significant difference in the ranking of iron overload by the two methods eg histology and MRI (sum of ranks = 1.5; p = 1). The MRI and Scheuer’s histological classifications were tightly correlated (rho = 0.866, p = 0.0035, Spearman’s coefficient), as were the absolute liver iron concentrations (LIC) at MRI (rho = 0.860, p = 0.0013, Spearman’s coefficient). The absolute liver iron concentrations at MRI were also highly correlated with Deugnier and Turlin’s histological scoring (rho = 0.841, p = 0.0033, Spearman’s coefficient).

Conclusions

This pilot study shows that liver iron determination based on signal-intensity-ratio MRI (Rennes University algorithm) very accurately identifies iron load in hemodialysis patients, by comparison with liver histology.

Shewanella algae Bacteremia in an End-stage Renal Disease Patient: A Case Report and Review of the Literature

A 71-year-old man was admitted because of nausea and abdominal pain. He was receiving an erythropoiesis-stimulating agent for anemia and dysregulated iron metabolism due to stage G5 chronic kidney disease. He had a history of raw fish intake and was diagnosed with infectious enterocolitis, which worsened and led to septic shock. Shewanella putrefaciens grew in the blood culture, but Shewanella algae was identified in a 16S rRNA gene sequence analysis. We herein report a case of S. algae bacteremia believed to have been transmitted orally. We also reviewed previous case reports on Shewanella infection in end-stage renal disease patients.

Plasma vitamin C levels in ESRD patients and occurrence of hypochromic erythrocytes

INTRODUCTION

The achievement of erythropoiesis in hemodialysis (HD) patients is typically managed with erythropoiesis-stimulating-agents (ESA's) and intravenous iron (IV-iron). Using this treatment strategy, HD patients frequently show an elevated fraction of red blood cells (RBC) with hemoglobin (Hb) content per cell that is below the normal range, called hypochromic RBC. The low Hb content per RBC is the result of the clinical challenge of providing sufficient iron content to the bone marrow during erythropoiesis. Vitamin C supplements have been used to increase Hb levels in HD patients with refractory anemia, which supports the hypothesis that vitamin C mobilizes iron needed for Hb synthesis.

METHODS

We conducted a cross-sectional survey in 149 prevalent HD patients of the percent hypochromic RBC, defined as RBC with Hb < 300 ng/uL of packed RBC, in relation to plasma vitamin C levels. We also measured high-sensitivity CRP, (hs-CRP), iron, and ferritin levels. and calculated ESA dose.

FINDINGS

High plasma levels of vitamin C were negatively associated with hypochromic RBC (P < 0.003), and high ESA doses were positively associated (P < 0.001). There was no significant association of hs-CRP with percent hypochromic RBC.

DISCUSSION

This finding supports the hypothesis that vitamin C mobilizes iron stores, improves iron delivery to the bone marrow, and increase the fraction of RBC with normal Hb content. Further research is warranted on development of protocols for safe and effective use of supplemental vitamin C for management of renal anemia.

Safety concerns about intravenous iron therapy in patients with chronic kidney disease

Anaemia in chronic kidney disease (CKD) is managed primarily with erythropoiesis-stimulating agents (ESAs) and iron therapy. Following concerns around ESA therapy, intravenous (IV) iron is being administered more and more worldwide. However, it is still unclear whether this approach is safe at very high doses or in the presence of very high ferritin levels. Some observational studies have shown a relationship between either high ferritin level or high iron dose and increased risk of death, cardiovascular events, hospitalization or infection. Others have not been able to confirm these findings. However, they suffer from indication biases. On the other hand, the majority of randomized clinical trials have only a very short follow-up (and thus drug exposure) and are inadequate to assess the mortality risk. None of them have tested the role of different iron doses on hard end points. With the lack of clear evidence coming from well-designed and large-scale studies, several data suggest that excessive iron therapy may be toxic in several aspects, ranging from iron overload to tissue damage from labile iron. A number of experimental and clinical data suggest that either excessive iron therapy or iron overload may be a possible culprit of atherogenesis. The process seems to be mediated by oxidative stress. Iron therapy should also be used cautiously in the presence of active infections, since iron is essential for bacterial growth. Recently, the European Medicines Agency officially raised concerns about rare hypersensitivity reactions following IV iron administration. The balance has been in favour of benefits. In several European countries, this has created a lot of confusion and somewhat slowed the run towards excessive use. Altogether, IV iron remains a mainstay of anaemia treatment in CKD patients. However, in our opinion, its excessive use should be avoided, especially in patients with high ferritin levels and when ESA agents are not contraindicated.

Diagnosis and Management of Iron Deficiency in CKD: A Summary of the NICE Guideline Recommendations and Their Rationale

The UK-based National Institute for Health and Care Excellence (NICE) has updated its guidance on iron deficiency and anemia management in chronic kidney disease. This report outlines the recommendations regarding iron deficiency and their rationale. Serum ferritin alone or transferrin saturation alone are no longer recommended as diagnostic tests to assess iron deficiency. Red blood cell markers (percentage hypochromic red blood cells, reticulocyte hemoglobin content, or reticulocyte hemoglobin equivalent) are better than ferritin level alone at predicting responsiveness to intravenous iron. When red blood cell markers are not available, a combination of transferrin saturation < 20% and ferritin level < 100ng/mL is an alternative. In comparisons of the cost-effectiveness of different iron status testing and treatment strategies, using percentage hypochromic red blood cells > 6% was the most cost-effective strategy for both hemodialysis and nonhemodialysis patients. A trial of oral iron replacement is recommended in people not receiving an erythropoiesis-stimulating agent (ESA) and not on hemodialysis therapy. For children receiving ESAs, but not treated by hemodialysis, oral iron should be considered. In adults and children receiving ESAs and/or on hemodialysis therapy, intravenous iron should be offered. When giving intravenous iron, high-dose low-frequency administration is recommended. For all children and for adults receiving in-center hemodialysis, low-dose high-frequency administration may be more appropriate.

New Options for Iron Supplementation in Maintenance Hemodialysis Patients

End-stage renal disease results in anemia caused by shortened erythrocyte survival, erythropoietin deficiency, hepcidin-mediated impairment of intestinal absorption and iron release, recurrent blood loss, and impaired responsiveness to erythropoiesis-stimulating agents (ESAs). Iron malabsorption renders oral iron products generally ineffective, and intravenous (IV) iron supplementation is required in most patients receiving maintenance hemodialysis (HD). IV iron is administered at doses far exceeding normal intestinal iron absorption. Moreover, by bypassing physiologic safeguards, indiscriminate use of IV iron overwhelms transferrin, imposing stress on the reticuloendothelial system that can have long-term adverse consequences. Unlike conventional oral iron preparations, ferric citrate has recently been shown to be effective in increasing serum ferritin, hemoglobin, and transferrin saturation values while significantly reducing IV iron and ESA requirements in patients treated with HD. Ferric pyrophosphate citrate is a novel iron salt delivered by dialysate; by directly reaching transferrin, its obviates the need for storing administered iron and increases transferrin saturation without increasing serum ferritin levels. Ferric pyrophosphate citrate trials have demonstrated effective iron delivery and stable hemoglobin levels with significant reductions in ESA and IV iron requirements. To date, the long-term safety of using these routes of iron administration in patients receiving HD has not been compared to IV iron and therefore awaits future investigations.

How the Target Hemoglobin of Renal Anemia Should Be

Renal anemia is caused by the deficiency of endogenous erythropoietin (Epo) due to renal dysfunction. We think that it is possible to slow the progression of chronic kidney disease (CKD) in case we initiate Epo early in pre-dialysis patients, especially in the non-diabetic population. Erythropoiesis stimulating agent (ESA) treatments targeting mild anemia (10-12 g/dl) can decrease the risk of occurrence of cardiovascular disease (CVD) in patients with hypertension, diabetes mellitus and congestive heart failure. As the large randomized controlled trials such as Cardiovascular Risk Reduction by Early Anemia Treatment with Epoetin Beta, Correction of Hemoglobin and Outcomes in Renal Insufficiency and Trial to Reduce Cardiovascular Events with Aranesp Thearpy in the Western countries suggested, we do not recommend high doses of ESA to achieve the target hemoglobin (Hb) level. The target Hb of >13 g/dl might lead to increase in the risk of CVD although maintaining a high Hb of >12 g/dl without ESA is not harmful for CKD patients. It is desirable to determine the target Hb in dialysis patients depending on their ages. Renal anemia should be monitored constantly to start ESA and iron replacement therapy at an appropriate time, while avoiding their excess in order to minimize the occurrence of CVD and other complications. Taken all the international guidelines and our clinical experiences together, we should consider administration of ESA when the Hb level becomes <11 g/dl in pre-dialysis patients and <10 g/dl in dialysis patients.

Iron therapy in chronic kidney disease: Recent changes, benefits and risks

Anemia is a common complication in patients with chronic kidney disease (CKD), mainly due to inadequate renal production of erythropoietin. In hemodialysis (HD) patients this condition may be aggravated by iron deficiency (absolute or functional). The correction of this anemia is usually achieved by treatment with erythropoiesis stimulating agents (ESAs) and iron (oral or intravenous). Studies questioning the safety of ESAs (especially at higher doses) changed the pattern of anemia treatment in CKD patients. According to the new guidelines, when transferrin saturation is lower than 30% and ferritin lower than 500 ng/mL, a trial with iron should be started, to avoid therapy with ESAs or at least to reduce the doses needed to treat the anemia. Recent reports showed increasing ferritin levels, towards values above 800 ng/mL, in CKD patients treated according to the guidelines. In this review we focus on the risks of the increased iron use to treat CKD anemia, namely, iron overload and toxicity, increased risk of infections, as well as mortality.

Reassessment of Iron Biomarkers for Prediction of Dialysis Iron Overload: An MRI Study

BACKGROUND AND OBJECTIVES

Iron overload among hemodialysis patients was previously considered rare but is now an increasingly recognized clinical situation. We analyzed correlations between iron biomarkers and the liver iron concentration (LIC) measured by magnetic resonance imaging (MRI), and examined their diagnostic accuracy for iron overload.

DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS

We performed a prospective cross-sectional study from 31 January 2005 to 31 August 2013 in the dialysis centre of a French community-based private hospital. A cohort of 212 hemodialysis patients free of overt inflammation or malnutrition, were treated for anemia with parenteral iron-sucrose and an erythropoesis-stimulating agent, in keeping with current clinical guidelines. Blinded measurements of hepatic iron stores were performed by T1 and T2* contrast MRI, and relationships were analysed using Spearman's coefficient, logistic regression and receiver-operator characteristic (ROC) curves.

RESULTS

Among the biological markers, only serum ferritin showed a strong correlation with LIC (rho= 0.52, 95% CI: 0.41-0.61, p< 0.0001, Spearman test). In logistic analysis, only serum ferritin correctly classified the overall cohort into patients with normal liver iron stores (LIC ≤ 50 μmol/g) and those with elevated liver iron stores (LIC > 50 μmol/g) (odds ratio 1.007; 95% CI: 1.004-1.010). Serum ferritin was the iron biomarker with the best discriminatory capacity in ROC curves analysis (area under the curve (AUC) = 0.767; 95% CI: 0.698-0.835). The optimal serum ferritin cutoffs were 160 μg/L for LIC > 50 μmol/g (mild iron overload) and 290 μg/L for LIC > 200 μmol/g (severe iron overload).

CONCLUSIONS

For clinical purposes, serum ferritin correctly reflects liver iron stores, as assessed by MRI, in hemodialysis patients without overt inflammation or malnutrition. These results strongly suggest that current ferritin target values should be lowered to avoid iron overload.

TRIAL REGISTRATION

ISRCTN Registry 80100088.