Iron management in chronic kidney disease: conclusions from a “Kidney Disease: Improving Global Outcomes” (KDIGO) Controversies Conference

Tissue Iron Distribution in Anemic Patients with End-Stage Kidney Disease: Results of a Pilot Study

Background/Objectives: Anemia is a frequent multifactorial co-morbidity in end-stage kidney disease (ESKD) associated with morbidity and poor QoL. Apart from insufficient erythropoietin formation, iron deficiency (ID) contributes to anemia development. Identifying patients in need of iron supplementation with current ID definitions is difficult since no good biomarker is available to detect actual iron needs. Therefore, new diagnostic tools to guide therapy are needed. Methods: We performed a prospective cohort study analyzing tissue iron content with MRI-based R2*-relaxometry in 20 anemic ESKD patients and linked it with iron biomarkers in comparison to 20 otherwise healthy individuals. Results: ESKD patients had significantly higher liver (90.1 s-1 vs. 36.1 s-1, p < 0.001) and spleen R2* values (119.8 s-1 vs. 19.3 s-1, p < 0.001) compared to otherwise healthy individuals, while their pancreas and heart R2* values did not significantly differ. Out of the 20 ESKD patients, 17 had elevated spleen and 12 had elevated liver R2* values. KDIGO guidelines (focusing on serum iron parameters) would recommend iron supplementation in seven patients with elevated spleen and four patients with elevated liver R2* values. Conclusions: These findings highlight that liver and especially spleen iron concentrations are significantly higher in ESKD patients compared to controls. Tissue iron overload diverged from classical iron parameters suggesting need of iron supplementation. Measurement of MRI-guided tissue iron distribution might help guide treatment of anemic ESKD patients.

The treatment effects and cardiovascular events of high-dose intravenous iron for hemodialysis patients with renal anemia: A systematic review and meta-analysis

BACKGROUND

Hemodialysis patients are common to have renal anemia in the nephrology practice. For the renal anemia, the high-dose iron from the intravenous route is an important treatment option. We can understand the treatment effects and cardiovascular events of high-dose intravenous iron reviewing the randomized clinical trials.

METHODS

We compared the high-dose and low-dose iron treatments to find if the high-dose intravenous iron can influence the hematological parameters more significantly than the low-dose iron. The cardiovascular events were also analyzed for the high-dose iron treatment. Six studies with a total of 2422 renal anemia patients under hemodialysis were enrolled. We focused the outcomes of hemoglobin, transferrin saturation percentage, ferritin, erythropoietin dose, and cardiovascular events.

RESULTS

The high-dose intravenous iron might be associated with a greater number of ferritin, transferrin saturation percentage, and hemoglobin. In addition, the erythropoietin dose was less needed to maintain the ideal hemoglobin range in the high-dose intravenous iron group.

CONCLUSIONS

In current meta-analysis, the high-dose intravenous iron might show the superior effects on the ferritin, transferrin saturation percentage, and hemoglobin levels and needed dose of erythropoietin when compared to low-dose iron treatment.

The efficacy and safety of molidustat for anemia in dialysis-dependent and non-dialysis-dependent chronic kidney disease patients: A systematic review and meta-analysis

Objective

Molidustat is a novel agent investigated for the treatment of anemia in both dialysisdependent (DD) and non-dialysis-dependent (NDD) patients. Its efficacy and safety are still unclear.

Methods

We searched five databases to identify randomized controlled trials comparing molidustat to erythropoiesis-stimulating agents (ESAs) or placebo in patients with anemia.

Results

Six studies containing 2025 eligible participants were identified. For NDD patients, the change in Hb levels from baseline (ΔHb) was significantly higher for molidustat than for placebo [mean difference (MD) = 1.47 (95 % CI: 1.18 to 1.75), P < 0.00001] and ΔHb was also significantly higher for molidustat than for ESAs [MD = 0.25 (95 % CI 0.09 to 0.40), P = 0.002]. For NDD patients, Δhepcidin was significantly lower for molidustat than for placebo [MD = -20.66 (95 % CI: -31.67 to -9.66), P = 0.0002] and Δhepcidin was also significantly lower for molidustat than for ESAs [MD = -24.51 (95 % CI: -29.12 to -19.90), P < 0.00001]. For NDD patients, Δiron was significantly lower for molidustat than for ESAs [MD = -11.85 (95 % CI: -15.52 to -8.18), P < 0.00001], and ΔTSAT was also significantly lower for molidustat than for ESAs [MD = -5.29 (95 % CI: -6.81 to -3.78), P < 0.00001]. For NDD patients, Δferritin was significantly lower for molidustat than for placebo [MD = -90.01 (95 % CI: -134.77 to -45.25), P < 0.00001]. However, for DD-CKD patients, molidustat showed an effect similar to that of ESAs on increasing the Hb level [MD = -0.18 (95 % CI: -0.47 to 0.11), P = 0.23], Δiron level [MD = 3.78 (95 % CI: -7.21 to 14.76), P = 0.5], Δferritin level [MD = 25.03 (95 % CI: -34.69 to 84.75), P = 0.41], and Δhepcidin level [MD = 1.20 (95 % CI: -4.36 to 6.76), P = 0.67]. For DD-CKD patients, compared with the placebo or ESA group, molidustat showed a significantly higher level on ΔTSAT[MD = 3.88 (95 % CI: 2.10 to 5.65), P < 0.0001] and a slightly increased level on ΔTIBC level [MD = 1.08 (95 % CI: -0.07 to 2.23), P = 0.07]. There was no significant difference in the incidence of severe adverse events (SAEs), death, and cardio-related adverse events between molidustat and the ESAs groups.

Conclusions

Moricizine can effectively improves Hb levels in NDD patients and corrects anemia in DD patients without increasing adverse event incidence.

Hypersensitive Reactions During Hemodialysis Treatment: What Do We Need to Know?

Kidney replacement therapies (KRTs) including hemodialysis (HD) are one of the treatment options for most of the patients with end-stage kidney disease. Although HD is vital for these patients, it is not hundred percent physiological, and various adverse events including hypersensitivity reactions may occur. Fortunately, these reactions are rare in total and less when compared to previous decades, but it is still very important for at least two reasons: First, the number of patients receiving kidney replacement treatment is increasing globally; and the cumulative number of these reactions may be substantial. Second, although most of these reactions are mild, some of them may be very severe and even lead to mortality. Thus, it is very important to have basic knowledge and skills to diagnose and treat these reactions. Hypersensitivity reactions can occur at any component of dialysis machinery (access, extracorporeal circuit, medications, etc.). The most important preventive measure is to avoid the allergen. However, even with very specific test, sometimes the allergen cannot be found. In mild conditions, HD can be contained with non-specific treatment (topical creams, antihistaminics, corticosteroids). In more severe conditions, treatment must be stopped immediately, blood should not be returned to patient, drugs must be stopped, and rules of general emergency treatment must be followed.

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.

Causal effects of human serum metabolites on occurrence and progress indicators of chronic kidney disease: a two-sample Mendelian randomization study

Background

Chronic kidney disease (CKD) is often accompanied by alterations in the metabolic profile of the body, yet the causative role of these metabolic changes in the onset of CKD remains a subject of ongoing debate. This study investigates the causative links between metabolites and CKD by leveraging the results of genomewide association study (GWAS) from 486 blood metabolites, employing bulk two-sample Mendelian randomization (MR) analyses. Building on the metabolites that exhibit a causal relationship with CKD, we delve deeper using enrichment analysis to identify the metabolic pathways that may contribute to the development and progression of CKD.

Methods

In conducting the Mendelian randomization analysis, we treated the GWAS data for 486 metabolic traits as exposure variables while using GWAS data for estimated glomerular filtration rate based on serum creatinine (eGFRcrea), microalbuminuria, and the urinary albumin-to-creatinine ratio (UACR) sourced from the CKDGen consortium as the outcome variables. Inverse-variance weighting (IVW) analysis was used to identify metabolites with a causal relationship to outcome. Using Bonferroni correction, metabolites with more robust causal relationships are screened. Additionally, the IVW-positive results were supplemented with the weighted median, MR-Egger, weighted mode, and simple mode. Furthermore, we performed sensitivity analyses using the Cochran Q test, MR-Egger intercept test, MR-PRESSO, and leave-one-out (LOO) test. Pathway enrichment analysis was conducted using two databases, KEGG and SMPDB, for eligible metabolites.

Results

During the batch Mendelian randomization (MR) analyses, upon completion of the inverse-variance weighted (IVW) approach, sensitivity analysis, and directional consistency checks, 78 metabolites were found to meet the criteria. The following four metabolites satisfy Bonferroni correction: mannose, N-acetylornithine, glycine, and bilirubin (Z, Z), and mannose is causally related to all outcomes of CKD. By pathway enrichment analysis, we identified eight metabolic pathways that contribute to CKD occurrence and progression.

Conclusion

Based on the present analysis, mannose met Bonferroni correction and had causal associations with CKD, eGFRcrea, microalbuminuria, and UACR. As a potential target for CKD diagnosis and treatment, mannose is believed to play an important role in the occurrence and development of CKD.

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.

Quantitative systems pharmacology model of erythropoiesis to simulate therapies targeting anemia due to chronic kidney disease

Anemia induced by chronic kidney disease (CKD) has multiple underlying mechanistic causes and generally worsens as CKD progresses. Erythropoietin (EPO) is a key endogenous protein which increases the number of erythrocyte progenitors that mature into red blood cells that carry hemoglobin (Hb). Recombinant human erythropoietin (rHuEPO) in its native and re-engineered forms is used as a therapeutic to alleviate CKD-induced anemia by stimulating erythropoiesis. However, due to safety risks associated with erythropoiesis-stimulating agents (ESAs), a new class of drugs, prolyl hydroxylase inhibitors (PHIs), has been developed. Instead of administering exogenous EPO, PHIs facilitate the accumulation of HIF-α, which results in the increased production of endogenous EPO. Clinical trials for ESAs and PHIs generally involve balancing decisions related to safety and efficacy by carefully evaluating the criteria for patient selection and adaptive trial design. To enable such decisions, we developed a quantitative systems pharmacology (QSP) model of erythropoiesis which captures key aspects of physiology and its disruption in CKD. Furthermore, CKD virtual populations of varying severities were developed, calibrated, and validated against public data. Such a model can be used to simulate alternative trial protocols while designing phase 3 clinical trials, as well as an asset for reverse translation in understanding emerging clinical data.

Infectious Risk and Variability of Hemoglobin Level in Patients Undergoing Hemodialysis

Introduction

In the management of anemia in chronic kidney disease, hemoglobin levels often fall below or exceed target ranges. Past retrospective cohort studies of patients undergoing hemodialysis with conventional erythropoiesis stimulating agents (ESAs) found that hemoglobin level fluctuations predicted mortality and cardiovascular adverse events; long-acting agents were thereafter widely available. An updated validation by a prospective cohort study was needed.

Methods

Using Cox regression models, we evaluated associations between hemoglobin variability and all-cause death, hospitalization, and cardiovascular, thrombotic, or infectious adverse event outcomes in 3063 hemodialysis patients' data from the Japanese Dialysis Outcomes and Practice Patterns Study (J-DOPPS) from 2012 to 2018.

Results

During a median follow-up time of 2.5 years, all-cause mortality was lowest in the first quartile and tended to be higher in groups with greater hemoglobin variability (hazard ratio [HR]: 95% confidence interval for the fourth quartile of an absolute value of hemoglobin variability: 1.44 [0.99-2.08], P for trend = 0.056). Infectious event incidence in these patients was also lower in the first quartile than for the other quartiles (P for trend < 0.01). The association was more pronounced in patients with lower serum ferritin levels or iron supplementation. Cardiovascular and thrombotic event incidence was not associated with hemoglobin variability.

Conclusions

Maintenance hemodialysis patients on ESA treatment with higher hemoglobin variability are at higher risk for all-cause mortality and particularly infectious events.

A Randomized Trial of Intravenous Iron Supplementation and Exercise on Exercise Capacity in Iron-Deficient Nonanemic Patients With CKD

Introduction

Patients with chronic kidney disease (CKD) are often iron deficient, even when not anemic. This trial evaluated whether iron supplementation enhances exercise capacity of nonanemic patients with CKD who have iron-deficiency.

Methods

Prospective, multicenter double-blind randomized controlled trial of nondialysis patients with CKD and iron-deficiency but without anemia (Hemoglobin [Hb] >110 g/l). Patients were assigned 1:1 to intravenous (IV) iron therapy, or placebo. An 8-week exercise program commenced at week 4. The primary outcome was the mean between-group difference in 6-minute walk test (6MWT) at 4 weeks. Secondary outcomes included 6MWT at 12 weeks, transferrin saturation (TSAT), serum ferritin (SF), Hb, renal function, muscle strength, functional capacity, quality of life, and adverse events at baseline, 4 weeks, and at 12 weeks. Mean between-group differences were analyzed using analysis of covariance models.

Results

Among 75 randomized patients, mean (SD) age for iron therapy (n = 37) versus placebo (n = 38) was 54 (16) versus 61 (12) years; estimated glomerular filtration rate (eGFR) (34 [12] vs. 35 [11] ml/min per 1.73 m2], TSAT (23 [12] vs. 21 [6])%; SF (57 [64] vs. 62 [33]) μg/l; Hb (122.4 [9.2] vs. 127 [13.2] g/l); 6MWT (384 [95] vs. 469 [142] meters) at baseline, respectively. No significant mean between-group difference was observed in 6MWT distance at 4 weeks. There were significant increases in SF and TSAT at 4 and 12 weeks (P < 0.02), and Hb at 12 weeks (P = 0.009). There were no between-group differences in other secondary outcomes and no adverse events attributable to iron therapy.

Conclusion

This trial did not demonstrate beneficial effects of IV iron therapy on exercise capacity at 4 weeks. A larger study is needed to confirm if IV iron is beneficial in nondialysis patients with CKD who are iron-deficient.

Sucrosomial® Iron: An Updated Review of Its Clinical Efficacy for the Treatment of Iron Deficiency

Iron deficiency (ID) and iron deficiency anemia (IDA) are highly prevalent worldwide. Oral iron salts, especially ferrous sulfate, are commonly used for the treatment of iron deficiency (ID). However, its use is associated with gastrointestinal side effects, thus compromising treatment compliance. Intravenous iron administration is a more costly and logistically complex alternative and is not risk-free, as infusion and hypersensitivity reactions may occur. Sucrosomial^® iron is an oral formulation consisting of ferric pyrophosphate conveyed by a phospholipid and sucrester matrix (sucrosome^®). Intestinal Sucrosomial^® iron absorption is mediated by enterocytes and M cells, through the paracellular and transcellular routes, and occurs mostly as intact particles. These pharmacokinetic properties of Sucrosomial^® iron result in higher iron intestinal absorption and excellent gastrointestinal tolerance compared to oral iron salts. The evidence derived from clinical studies supports the use of Sucrosomial^® iron as a valid first option for the treatment of ID and IDA, especially for subjects who are intolerant or refractory to conventional iron salts. Newer evidence also demonstrates the effectiveness of Sucrosomial^® iron, with a lower cost and fewer side effects, in certain conditions usually treated with IV iron in current clinical practice.

Associations of Iron Sucrose and Intradialytic Blood Pressure

RATIONALE & OBJECTIVE

Intradialytic hypotension and intradialytic hypertension are associated with morbidity and mortality in hemodialysis (HD). Many factors can contribute to intra-HD blood pressure (BP) changes, such as drugs with vasoactive properties that can destabilize an already tenuous BP. Intravenous iron sucrose is commonly administered to correct iron deficiency; however, its reported associations with altered hemodynamics have not been consistent.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

950 outpatients receiving maintenance HD.

EXPOSURE

Iron sucrose administered during HD.

OUTCOME

Intradialytic hypotension, intradialytic hypertension, systolic blood pressure parameters.

ANALYTICAL APPROACH

Unadjusted and adjusted Poisson and linear repeated measures regression models.

RESULTS

The mean age of patients included in the study was 53±22 years, 43% were female, and 38% were Black. Mean pre-HD SBP was 152±26 (SD) mm Hg. At baseline, the patients who received higher doses of iron sucrose tended to have diabetes, have longer HD sessions, and have a higher frequency of erythropoiesis-stimulating agent use, compared with those who did not receive iron sucrose. In adjusted models, higher doses of iron sucrose were associated with an 11% lower rate of intradialytic hypotension (incidence rate ratio [IRR] for iron sucrose≥100mg vs 0 mg, 0.89 [95% CI, 0.85-0.94]). In adjusted analyses, the administration of higher doses of iron sucrose during HD was associated with intradialytic hypertension (IRR for iron sucrose≥100mg vs 0 mg, 1.07 [95% CI, 1.04-1.10]).

LIMITATIONS

Nonavailability of the precise iron sucrose formulation (volume), laboratory data for each HD session, and outpatient medications. Objective measures of volume status, home medications, and symptom data were not recorded in this study.

CONCLUSIONS

We observed an independent association of intravenous iron sucrose administration during HD with a lower risk of intradialytic hypotension and higher risk of intradialytic hypertension. Future studies to better understand the mechanisms underlying these associations are warranted.

PLAIN-LANGUAGE SUMMARY

Intradialytic hypotension and intradialytic hypertension are common among patients on hemodialysis, and they are associated with morbidity and mortality. Although many factors may contribute to these risks, medications administered during hemodialysis play an important role. We studied the significance of the intravenous iron sucrose used to treat iron deficiency and the impact it may have on blood pressure during dialysis. In our study of 950 outpatient hemodialysis patients, we observed that administration of iron sucrose was associated with higher systolic blood pressure (during and after hemodialysis sessions) as well as a lower risk of intradialytic hypotension. We also observed that higher doses of iron sucrose are associated with the development of intradialytic hypertension.

Lysosomal nanotoxicity: Impact of nanomedicines on lysosomal function

Although several nanomedicines got clinical approval over the past two decades, the clinical translation rate is relatively small so far. There are many post-surveillance withdrawals of nanomedicines caused by various safety issues. For successful clinical advancement of nanotechnology, it is of unmet need to realize cellular and molecular foundation of nanotoxicity. Current data suggest that lysosomal dysfunction caused by nanoparticles is emerging as the most common intracellular trigger of nanotoxicity. This review analyzes prospect mechanisms of lysosomal dysfunction-mediated toxicity induced by nanoparticles. We summarized and critically assessed adverse drug reactions of current clinically approved nanomedicines. Importantly, we show that physicochemical properties have great impact on nanoparticles interaction with cells, excretion route and kinetics, and subsequently on toxicity. We analyzed literature on adverse reactions of current nanomedicines and hypothesized that adverse reactions might be linked with lysosomal dysfunction caused by nanomedicines. Finally, from our analysis it becomes clear that it is unjustifiable to generalize safety and toxicity of nanoparticles, since different particles possess distinct toxicological properties. We propose that the biological mechanism of the disease progression and treatment should be central in the optimization of nanoparticle design.

Effects of hypoxia-inducible factor prolyl hydroxylase inhibitors versus erythropoiesis-stimulating agents on iron metabolism and inflammation in patients undergoing dialysis: A systematic review and meta-analysis

Aims

This study aimed to evaluate the effects of hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) on iron metabolism and inflammation in dialysis-dependent chronic kidney disease (DD-CKD) patients.

Methods

PubMed, Embase, Web of Science, Cochrane Library, and ClinicalTrials.gov websites were searched for randomized controlled trials (RCTs) investigating HIF-PHIs versus ESAs for DD-CKD patients.

Key findings

Twenty studies with 14,737 participants were included in the meta-analysis, which demonstrated no significant difference in the effect of transferrin saturation and ferritin between HIF-PHIs and the ESAs group (MD, 0.65; 95%CI, -0.45 to 1.75; very low certainty; SMD, -0.03; 95% CI, -0.13 to 0.07; low certainty). However, HIF-PHIs significantly increased the iron (MD, 2.30; 95% CI, 1.40 to 3.20; low certainty), total iron-binding capacity (SMD, 0.82; 95% CI, 0.66 to 0.98; low certainty), and transferrin (SMD, 0.90; 95%CI, 0.74 to 1.05; moderate certainty) levels when compared with the ESAs group. In contrast, the hepcidin level and dosage of intravenous iron were significantly decreased in the HIF-PHIs group compared with the ESAs group (MD, -15.06, 95%CI, -21.96 to -8.16; low certainty; MD, -18.07; 95% CI, -30.05 to -6.09; low certainty). The maintenance dose requirements of roxadustat were independent of baseline CRP or hsCRP levels with respect to the effect on inflammation.

Significance

HIF-PHIs promote iron utilization and reduce the use of intravenous iron therapy. Furthermore, HIF-PHIs, such as roxadustat, maintain the erythropoietic response independent of the inflammatory state. Thus, HIF-PHIs may be an alternative treatment strategy for anemia in DD-CKD patients, where ESA is hyporesponsive due to iron deficiency and inflammation.

A Rationally Designed Complex Replenishes the Transferrin Iron Pool Directly and with High Specificity

Many forms of anemia are caused or complicated by pathologic restriction of iron (Fe). Chronic inflammation and certain genetic mutations decrease the activity of ferroportin, the only Fe-exporter protein, so that endogenously recycled or nutritionally absorbed Fe cannot be exported to the extracellular Fe carrier protein transferrin for delivery to the bone marrow. Diminished ferroportin activity renders anemia correction challenging as Fe administered intravenously or through nutritional supplementation is trafficked through the ferroportin-transferrin axis. Utilizing judicious application of coordination chemistry principles, we designed an Fe complex (Fe-BBG) with solution thermodynamics and Fe dissociation kinetics optimized to replenish the transferrin-Fe pool rapidly, directly, and with precision. Fe-BBG is unreactive under conditions designed to force redox cycling and production of reactive oxygen species. The BBG ligand has a low affinity for divalent metal ions and does not compete for binding of other endogenously present ions including Cu and Zn. Treatment with Fe-BBG confers anemia correction in a mouse model of iron-refractory iron-deficiency anemia. Repeated exposure to Fe-BBG did not cause adverse clinical chemistry changes or trigger the expression of genes related to oxidative stress or inflammation. Fe-BBG represents the first entry in a promising new class of transferrin-targeted Fe replacement drugs.

Maintenance intravenous iron in hemodialysis patients to minimize erythropoietin doses: a double-blinded, randomized controlled trial (the MAINTAIN IRON trial)

In patients on chronic hemodialysis, there is no standard protocol for maintenance iron supplementation. This study aimed to compare two fixed-dose intravenous (IV) iron protocols to reduce erythropoiesis-stimulating agents (ESA). We conducted a double-blinded, randomized controlled study on hemodialysis patients having ferritin levels between 200 and 700 ng/dl and transferrin saturation values between 20 and 40%. Patients were assigned to receive either 100 or 200 mg of IV iron each month. ESA was adjusted every month to keep Hb between 10 and 12 g/dl. ESA dose at 12 months was the primary outcome. The secondary outcomes were all-cause mortality, cardiovascular events, absolute iron deficiency anemia (IDA), blood transfusion, adverse events, and iron withholding rate. Of the 79 eligible patients, 40 received 100 mg of IV iron, while 39 received 200 mg. At month 12, the mean monthly ESA dose in the 100-mg IV iron group was 35,706 ± 21,637 IU, compared to 26,382 ± 14,983 IU in the 200-mg group (P = 0.03). IDA was found in twelve patients (30%) in the 100-mg group and four patients (10.5%) in the 200-mg group (P = 0.05). In each group, three patients died (P = 0.9). Hospitalization, venous access thrombosis, and infection rates were similar in both groups. The withholding rate of IV iron was higher in 200-mg group (25% vs. 64.1%), but the protocol compliance was found more in 100-mg group (50% vs. 28.2%) (P = 0.001). In conclusion, monthly 200-mg IV iron infusions significantly reduce ESA doses but have a higher withholding rate. (Funded by the Kidney Foundation of Thailand and the Research Group in Nephrology and Renal Replacement Therapy from the Faculty of Medicine, Thammasat University).Thai Clinical Trials Registry number, TCTR20190707001.

Osteocyte Egln1/Phd2 links oxygen sensing and biomineralization via FGF23

Osteocytes act within a hypoxic environment to control key steps in bone formation. FGF23, a critical phosphate-regulating hormone, is stimulated by low oxygen/iron in acute and chronic diseases, however the molecular mechanisms directing this process remain unclear. Our goal was to identify the osteocyte factors responsible for FGF23 production driven by changes in oxygen/iron utilization. Hypoxia-inducible factor-prolyl hydroxylase inhibitors (HIF-PHI) which stabilize HIF transcription factors, increased Fgf23 in normal mice, as well as in osteocyte-like cells; in mice with conditional osteocyte Fgf23 deletion, circulating iFGF23 was suppressed. An inducible MSC cell line ('MPC2') underwent FG-4592 treatment and ATACseq/RNAseq, and demonstrated that differentiated osteocytes significantly increased HIF genomic accessibility versus progenitor cells. Integrative genomics also revealed increased prolyl hydroxylase Egln1 (Phd2) chromatin accessibility and expression, which was positively associated with osteocyte differentiation. In mice with chronic kidney disease (CKD), Phd1-3 enzymes were suppressed, consistent with FGF23 upregulation in this model. Conditional loss of Phd2 from osteocytes in vivo resulted in upregulated Fgf23, in line with our findings that the MPC2 cell line lacking Phd2 (CRISPR Phd2-KO cells) constitutively activated Fgf23 that was abolished by HIF1α blockade. In vitro, Phd2-KO cells lost iron-mediated suppression of Fgf23 and this activity was not compensated for by Phd1 or -3. In sum, osteocytes become adapted to oxygen/iron sensing during differentiation and are directly sensitive to bioavailable iron. Further, Phd2 is a critical mediator of osteocyte FGF23 production, thus our collective studies may provide new therapeutic targets for skeletal diseases involving disturbed oxygen/iron sensing.

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.

[Evaluation of serum iron as a predictor of a hemoglobin response to injectable iron treatment in chronic hemodialysis patients]

BACKGROUND

The detection and correction of iron deficiency are essential for the treatment of anemia in chronic hemodialysis patients. The aim of our study was to assess the ability of serum iron to predict hemoglobin response to intravenous iron supplementation in hemodialysis patients.

METHODS

It is a retrospective study in 91 hemodialysis patients during 2016 at Clermont-Ferrand University Hospital for whom intravenous iron supplementation had been started. A responder patient was defined as an increase in hemoglobin greater than or equal to 1 g/dL/month and/or a decrease in the dose of erythropoiesis stimulating agent after two months of iron supplementation.

RESULTS

In responding patients, serum iron was significantly lower (6.7 ± 2.7 μmol/L) compared to non-responding patients (8.9±2.9 μmol/L; P<0.001). The positive response to iron supplementation was significantly associated with low serum iron (odds ratio = 0.58 [0.42-0.81]; P=0.002) in a logistic regression model taking into account ferritin, transferrin saturation coefficient, dose variation monthly iron and erythropoiesis stimulating agent and the duration of dialysis. The area under the receiver operating characteristic curve of serum iron, ferritin and transferrin saturation coefficient to predict the response to iron supplementation were 0.72, 0.51 and 0.64, respectively (serum iron versus ferritin [P=0.006] and serum iron versus transferrin saturation coefficient [P=0.04]). The sensitivity for serum iron below 7.5 μmol/L was better than that for ferritin below 86 ng/mL (P<0.001) and the specificity for serum iron below 7.5 μmol/L was better than that for TSC less than 19% (P=0.02).

CONCLUSION

Serum iron below 7.5 μmol/L can predict the success of the response to iron supplementation in chronic hemodialysis patients.

[Management of iron deficiency in chronic kidney disease: Review and proposed algorithm]

Iron deficiency is very common in chronic kidney disease, even before the dialysis stage. It is an independent factor of morbidity and mortality in patients with non-dialysis chronic kidney disease. During chronic kidney disease, iron deficiency is defined by a transferrin saturation <20% and/or a serum ferritin <100 μg/L. In France, about half of non-dialysis chronic kidney disease patients have absolute iron deficiency (transferrin saturation <20% and serum ferritin <100 μg/L) and/or functional iron deficiency (transferrin saturation <20% and serum ferritin >100 μg/L). Despite this, iron deficiency is usually not investigated. In fact, more than 60% of nephrologists do not assess iron status at least once a year. In addition, iron deficiency is rarely treated: only 12% of patients are prescribed oral or intravenous iron. Early detection and treatment are fundamental and should be systematic. In order to help improve the management of iron deficiency among non-dialysis chronic kidney disease patients, we propose an algorithm that takes into account current recommendations and the most recent data from the literature. Initial blood test requires the measurement of hemoglobin concentration, transferrin saturation and serum ferritin. A transferrin saturation <20% establishes the diagnosis of iron deficiency and the serum ferritin level points towards an absolute or functional deficiency. The combination of both values makes it possible to adapt the treatment, particularly in an inflammatory context where oral iron is not effective.

Role of Iron and Iron Overload in the Pathogenesis of Invasive Fungal Infections in Patients with Hematological Malignancies

Iron is an essential trace metal necessary for the reproduction and survival of fungal pathogens. The latter have developed various mechanisms to acquire iron from their mammalian hosts, with whom they participate in a continuous struggle for dominance over iron. Invasive fungal infections are an important problem in the treatment of patients with hematological malignancies, and they are associated with significant morbidity and mortality. The diagnosis of invasive clinical infections in these patients is complex, and the treatment, which must occur as early as possible, is difficult. There are several studies that have shown a possible link between iron overload and an increased susceptibility to infections. This link is also relevant for patients with hematological malignancies and for those treated with allogeneic hematopoietic stem cell transplantation. The role of iron and its metabolism in the virulence and pathogenesis of various invasive fungal infections is intriguing, and so far, there is some evidence linking invasive fungal infections to iron or iron overload. Clarifying the possible association of iron and iron overload with susceptibility to invasive fungal infections could be important for a better prevention and treatment of these infections in patients with hematological malignancies.

Randomized trial of sucrosomial iron supplementation in patients with chemotherapy-related anemia treated with ESA

BACKGROUND

Iron supplementation improves the erythropoiesis-stimulating agents' (ESAs) response in chemotherapy-related anemia. The primary aim of our study is to assess the efficacy of sucrosomial iron, a new oral iron formulation, in cancer patients with chemotherapy-induced anemia treated with ESAs. The secondary objectives included the efficacy into two subgroups of patients (iron replete and functional iron deficiency) between the two study arms, safety and the effect on transfusion need.

METHODS

In this randomized, multicentre, open-label, phase III clinical trial, 60 cancer patients were enrolled. Each patient was randomly assigned (1:1) to receive 12 weeks of oral sucrosomial iron at the dose of 30 mg daily in combination with ESAs or no supplementation to ESA treatment. The endpoint considered for efficacy was the proportion of patients achieving complete hematological response at 12 weeks (increase in Hb > 2 g/dL from baseline, without RBC transfusions in the previous 28 days or achieving Hb ≥ 12 g/dL).

RESULTS

There was a statistically significant association between oral sucrosomial iron supplementation in combination with ESAs and the achievement of a complete hematological response. This response was achieved within 12 weeks by 31% of patients in the control group and by 52% of patients supplemented with oral sucrosomial iron. A trend of greater response in sucrosomial iron arm was found in both subgroups. No difference was observed about safety and transfusion need.

CONCLUSIONS

Sucrosomial iron is well tolerated and its combination with ESAs improves the hematological response in cancer patients with chemotherapy-related anemia.

TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION

This study has been reviewed by the Institutional Ethics Committee of the IRCCS Policlinico San Matteo Foundation, Pavia, Italy (28/04/2015; prot. N. 20,150,002,059), and by the Institutional Ethics Committee of the other Italian oncological centers involved in this study.

[Prevalence of iron deficiency in patients with non-dialysis chronic kidney disease: The CARENFER national, multicentre, observational study]

INTRODUCTION

Iron deficiency is common and associated with worse outcomes in patients with non-dialysis chronic kidney disease. We performed a national, multicentre, observational and transversal study to assess the prevalence of iron deficiency as well as current iron deficiency screening practices in this population.

PATIENTS AND METHODS

A total of 25 nephrology centres in France participated in the study. All adult non-dialysis chronic kidney disease patients who met the inclusion (GFR>15mL/min/1.73m²) and exclusion criteria and provided consent were systematically recruited over a 4-week inclusion period. Investigators were asked to perform a blood test (hemoglobin concentration, serum iron, serum ferritin and transferrin saturation) and to complete a questionnaire about their iron status monitoring practices. The primary objective was to assess the prevalence of iron deficiency (serum ferritin<100μg/L and/or transferrin saturation<20%). Secondary objectives were to evaluate the prevalence of absolute iron deficiency (serum ferritin<100μg/L and transferrin saturation<20%) and functional iron deficiency (serum ferritin≥100μg/L and transferrin saturation<20%), the prevalence of iron deficiency according to haemoglobin concentration and chronic kidney disease stage, the proportion of centres that perform routine evaluation of iron status and the number of patients receiving iron supplementation.

RESULTS

A total of 1211 patients with non-dialysis chronic kidney disease were included in the analysis. The overall prevalence of iron deficiency was 47.1%. The rates of absolute iron deficiency and functional iron deficiency and anaemia were 13.4% and 17.1%, respectively. Among the 25 participating centres, 12 reported routine assessment of iron status in non-dialysis chronic kidney disease patients.

CONCLUSION

In this observational study, a high prevalence of iron deficiency was observed among non-dialysis chronic kidney disease patients. Less than half of participating centres reported routine assessment of iron status.

Clinical parameters among patients in Japan with anemia and non-dialysis-dependent chronic kidney disease with and without diabetes mellitus who received roxadustat

Background

Roxadustat is an oral hypoxia-inducible factor prolyl hydroxylase inhibitor for treating anemia of chronic kidney disease (CKD). This post hoc analysis of a Japanese, open-label, partially randomized, phase 3 study in patients with non-dialysis-dependent (NDD) CKD evaluated disease state–related parameters among patients with and without diabetes mellitus who received roxadustat. In the 1517-CL-0310 study (NCT02988973), roxadustat was noninferior to darbepoetin alfa for change in average hemoglobin levels at Weeks 18–24 from baseline who received roxadustat.

Methods

Patients enrolled in the 1517-CL-0310 study who received roxadustat were included in this post hoc analysis. Hematologic (hemoglobin, reticulocyte/erythrocyte ratio, mean corpuscular volume [MCV], and mean corpuscular hemoglobin [MCH]), iron-related (ferritin, total iron-binding capacity, transferrin, ceruloplasmin, and hepcidin), metabolic (HbA1c, glycated albumin, total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol), and renal (eGFR) parameters were summarized descriptively by visit through Week 52.

Results

Among 201 included patients, 105 (52.2%) and 96 (47.8%) were in the Diabetes and No Diabetes subgroups, respectively. There were no clinically meaningful differences through Week 52 for most hematologic, iron-related, metabolic, or renal parameters between patients in the Diabetes and No Diabetes subgroups. MCV and MCH remained lower and HbA1c and glycated albumin remained higher in patients in the Diabetes subgroup through Week 52. Both subgroups experienced a similar benefit from roxadustat in maintaining hemoglobin levels in the target range of 10–12 g/dL.

Conclusion

Roxadustat maintained hemoglobin levels in the target range with similar clinical parameters irrespective of diabetes mellitus presence at baseline.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10157-022-02225-w.

Analysis of Adverse Events and Intravenous Iron Infusion Formulations in Adults With and Without Prior Infusion Reactions

IMPORTANCE

Although iron deficiency is common, it remains unclear which iron repletion strategy is associated with the lowest rate of infusion-related adverse events, and how patients with history of infusion reaction should be managed.

OBJECTIVE

To evaluate rates of infusion reactions among 4 commonly used intravenous iron repletion strategies and determine how readministration was managed in patients with history of reaction.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included all patients receiving intravenous iron infusion from January 1, 2015, to September 7, 2021, at 6 centers in Portland, Oregon. Participants included a total of 12 237 patients with iron deficiency, not restricted by etiology. Statistical analysis was performed from September to October 2021.

EXPOSURES

Type of intravenous iron formulation and concurrent administration of diphenhydramine, epinephrine, famotidine, and/or hydrocortisone, used as surrogate maker of infusion reaction.

MAIN OUTCOMES AND MEASURES

Incidence of adverse events, including severe events requiring epinephrine, stratified by type of iron formulation, and in patients who received premedication or with history of infusion-related reaction receiving subsequent doses.

RESULTS

Among 35 737 unique iron infusions (12 237 patients [9480 (77.5%) women; 717 (5.9%) Black; 10 250 (83.7%) White; mean (SD) age of 51 (20) years]), comprising 22 309 iron sucrose doses, 9067 iron dextran total doses (1771 preceded by test dose, 56 test doses alone), 3147 ferumoxytol doses, and 1214 ferric carboxymaltose doses, incidence of adverse events was 3.9% (n = 1389; 95% CI, 3.7%-4.1%). Rate of infusion events differed among iron formulations: 4.3% (n = 970; 95% CI, 4.1%-4.6%) iron sucrose, 3.8% (n = 345, 95% CI: 3.4%-4.2%) iron dextran (test and full doses or test dose alone), 1.8% (n = 57; 95% CI, 1.4%-2.3%) ferumoxytol, and 1.4% (n = 17, 95% CI, 0.8%-2.3%) ferric carboxymaltose (P < .001). Severe adverse events were exceedingly rare with only 2 documented epinephrine administrations, both associated with iron dextran. Incidence of adverse events among those who received premedication was 23-fold higher compared with those who did not (38.6% vs 1.7%, χ21 = 7324.8; P < .001). Among 873 patients with history of infusion reaction who underwent readministration, the majority received the same formulation, which was associated with significantly higher reaction rate particularly if premedication was administered (68% [95% CI, 64%-72%] vs 32% [95% CI, 26%-41%], respectively), compared with those who received an alternate formulation (21% [95% CI, 11%-35%] vs 5% [95% CI, 2%-12%], respectively) (P < .001).

CONCLUSIONS AND RELEVANCE

These data, and the preponderance of published evidence, suggest that intravenous iron is generally well tolerated with exceedingly low risk of severe reaction, use of premedication and test doses are unnecessary, and that optimal prevention and management of infusion-related reactions warrant further study.

Efficacy and safety of intravenous iron with different frequencies for renal anaemia: A systematic review and meta-analysis

WHAT IS KNOWN AND OBJECTIVE

To evaluate the efficacy and safety of intravenous iron supplementation in patients with renal anaemia.

METHODS

We searched the PubMed, Embase, Cochrane Library, and Web of Science from their inception until 17 September 2021, for randomized controlled trials (RCTs) to evaluate the efficacy and safety of intravenous iron at different frequencies. The observed efficacy indicators included transfer saturation (TSAT), serum ferritin (SF) and haemoglobin (HGB). Outcomes of interest included allergies, infections, all-cause mortality and cardiovascular events.

RESULTS AND DISCUSSION

Of the 751 eligible studies, 7 RCTs met the inclusion criteria. The RCTs showed that there were no significant differences between the low-frequency high-dose group (1-2 doses, >200 mg/dose) and the high-frequency low-dose group (4-5 doses, ≤200 mg/dose) in the increase in TSAT (WMD = 1.90; 95% CI = -2.04 to 5.84; I²  = 0%), SF (WMD = 15.70; 95% CI = -32.20 to 70.61; I²  = 0%) and HGB (WMD = -0.00; 95% CI = -0.43 to 0.42; I²  = 0%). There was also no significant difference in the occurrence of outcome events, including allergies (RR = 1.84; 95% CI = 0.95 to 3.57; I²  = 45%), infections (RR = 0.61; 95% CI = 0.20-1.86; I²  = 0%), cardiovascular events (RR = 0.88; 95% CI = 0.67-1.15; I²  = 48%) and all-cause mortality (RR = 0.74; 95% CI = 0.40-1.35; I²  = 0%).

WHAT IS NEW AND CONCLUSION

Frequencies of intravenous iron supplementation with similar doses share similar safety and efficacy in patients with renal anaemia. However, a single dose or two doses of intravenous iron are more cost-effective and patient friendly. These findings may provide evidence for the clinical application of intravenous iron supplementation for patients with renal anaemia.

Long-Term Intravenous Iron Therapy and Morbidity in Hemodialysis Patients

Objective: The aim of this study was to describe long-term intravenous iron therapy-associated morbidity in hemodialysis patients from a single Hemodialysis Center. Material and methods: We conducted an observational retrospective cohort study from 01 January to 31 December 2015. Two hundred and twenty prevalent patients on maintenance hemodialysis therapy for at least 12 months (mean age 53±13 years, 56% males, median hemodialysis vintage 5 (1-26) years) were included. Diabetic nephropathy as primary kidney disease, pregnancy and incomplete data records regarding study aims were exclusion criteria. We compared the frequency, duration and causes of hospitalizations in iron sucrose-treated versus gender and age-matched iron non-treated patients. Differences between groups were assessed using Chi-square and Kruskal-Wallis H tests. A p value μ0.05 was considered statistically significant. Results: From the entire cohort, 68% were iron-treated. One in five patients were treated with higher doses (400 mg monthly), and lower doses were used (100-200 mg monthly) in 80% of patients. There were no differences regarding the rates of admission between the two groups (56/100 patient-years in the iron sucrose-treated vs. 50/100 patient-years in the iron-untreated group, p=0.1). Still, the hospitalization rate significantly increased with the administered iron dose (0.4 vs. 0.7 vs. 0.8/100 patient-years for 100 mg vs. 200 mg vs. 400 mg monthly, respectively, p=0.006). Hospitalization rates due to infectious and cardiovascular diseases were similar for both groups (12/100 patient-years vs. 5.7/100 patient-years, p=0.3 and 11.3/100 patient-years vs. 4.3/100 patient-years, p=0.2, respectively). Conclusion: Higher doses of intravenous iron sucrose appear to be associated with an elevated risk of hospitalization. Nonetheless, long-term intravenous iron therapy seems to have a limited influence in terms of specific cause of morbidity in non-diabetic hemodialysis patients.

Proteinuric chronic kidney disease is associated with altered red blood cell lifespan, deformability and metabolism

Anemia is a common complication of chronic kidney disease, affecting the quality of life of patients. Among various factors, such as iron and erythropoietin deficiency, reduced red blood cell (RBC) lifespan has been implicated in the pathogenesis of anemia. However, mechanistic data on in vivo RBC dysfunction in kidney disease are lacking. Herein, we describe the development of chronic kidney disease-associated anemia in mice with proteinuric kidney disease resulting from either administration of doxorubicin or an inducible podocin deficiency. In both experimental models, anemia manifested at day 10 and progressed at day 30 despite increased circulating erythropoietin levels and erythropoiesis in the bone marrow and spleen. Circulating RBCs in both mouse models displayed altered morphology and diminished osmotic-sensitive deformability together with increased phosphatidylserine externalization on the outer plasma membrane, a hallmark of RBC death. Fluorescence-labelling of RBCs at day 20 of mice with doxorubicin-induced kidney disease revealed premature clearance from the circulation. Metabolomic analyses of RBCs from both mouse models demonstrated temporal changes in redox recycling pathways and Lands' cycle, a membrane lipid remodeling process. Anemic patients with proteinuric kidney disease had an increased proportion of circulating phosphatidylserine-positive RBCs. Thus, our observations suggest that reduced RBC lifespan, mediated by altered RBC metabolism, reduced RBC deformability, and enhanced cell death contribute to the development of anemia in proteinuric kidney disease.

Serum Biomarkers of Iron Stores Are Associated with Increased Risk of All-Cause Mortality and Cardiovascular Events in Nondialysis CKD Patients, with or without Anemia

BACKGROUND

Approximately 30%-45% of patients with nondialysis CKD have iron deficiency. Iron therapy in CKD has focused primarily on supporting erythropoiesis. In patients with or without anemia, there has not been a comprehensive approach to estimating the association between serum biomarkers of iron stores, and mortality and cardiovascular event risks.

METHODS

The study included 5145 patients from Brazil, France, the United States, and Germany enrolled in the Chronic Kidney Disease Outcomes and Practice Patterns Study, with first available transferrin saturation (TSAT) and ferritin levels as exposure variables. We used Cox models to estimate hazard ratios (HRs) for all-cause mortality and major adverse cardiovascular events (MACE), with progressive adjustment for potentially confounding variables. We also used linear spline models to further evaluate functional forms of the exposure-outcome associations.

RESULTS

Compared with patients with a TSAT of 26%-35%, those with a TSAT ≤15% had the highest adjusted risks for all-cause mortality and MACE. Spline analysis found the lowest risk at TSAT 40% for all-cause mortality and MACE. Risk of all-cause mortality, but not MACE, was also elevated at TSAT ≥46%. Effect estimates were similar after adjustment for hemoglobin. For ferritin, no directional associations were apparent, except for elevated all-cause mortality at ferritin ≥300 ng/ml.

CONCLUSIONS

Iron deficiency, as captured by TSAT, is associated with higher risk of all-cause mortality and MACE in patients with nondialysis CKD, with or without anemia. Interventional studies evaluating the effect on clinical outcomes of iron supplementation and therapies for alternative targets are needed to better inform strategies for administering exogenous iron.

Safe and Effective Treatment for Anemic Patients With Chronic Kidney Disease: An Updated Systematic Review and Meta-Analysis on Roxadustat

Background: Roxadustat is a new oral drug for anemia in chronic kidney disease (CKD). This study aimed to synthesize the evidence from randomized controlled trial (RCT)-based studies that estimated the efficacy and safety of roxadustat in anemia patients with non-dialysis-dependent (NDD) and dialysis-dependent (DD) CKD.

Methods: We searched the PubMed, Web of Science, and Cochrane Central Register of Controlled Trials (CENTRAL) databases for related published studies. Moreover, we manually searched relevant pharmaceutical company websites and two international clinical trial registers to search for published and unpublished RCTs comparing roxadustat with erythropoietin-stimulating agents (ESAs) or placebo.

Results: Fifteen RCTs (seven for DD-CKD patients, eight for NDD-CKD patients) were included in the meta-analysis, with 10,189 patients, 4,810 DD-CKD patients, and 5,379 NDD-CKD patients enrolled. Compared with ESAs (epoetin alfa or darbepoetin alfa) and placebo, roxadustat raised the hemoglobin level [weighted mean difference (WMD): 0.82 g/dL; 95% confidence interval (CI): 0.43–1.21], transferrin level (WMD: 0.5 g/L; 95% CI: 0.34–0.65), and TIBC level (WMD: 41.79 μg/dL; 95% CI: 38.67–44.92) and lowered the hepcidin level (WMD: −37.38 ng/ml; 95% CI: −46.63– −28.12) in both the DD-CKD and NDD-CKD patients with renal anemia. Roxadustat improved hemoglobin response and lowered the ferritin and TAST levels in the NDD-CKD patients but not in the DD-CKD patients. Furthermore, there was no difference between the treatment-emergent adverse events (TEAEs) of roxadustat and that of ESAs or placebo. But the incidence of serious TEAEs in the roxadustat group was significantly higher with NDD-CKD patients (OR: 1.15; 95% CI: 1.02–1.29).

Conclusion: This study confirmed that roxadustat therapy could alleviate the anemia of DD-CKD and NDD-CKD patients by raising the hemoglobin level and regulating iron metabolism, but increased serious incidences of treatment-emergent adverse events (TEAEs) in NDD-CKD patients.

Roxadustat treatment for anemia in peritoneal dialysis patients: A randomized controlled trial

BACKGROUND/PURPOSE

Roxadustat, a first-in-class hypoxia-inducible factor prolyl hydroxylase inhibitor, promotes erythropoiesis and regulates iron metabolism. This study investigated the efficacy and safety of roxadustat in Chinese patients with anemia on peritoneal dialysis (PD).

METHODS

One hundred and twenty-nine patients were randomized and treated with roxadustat (n = 86) or erythropoiesis-stimulating agents (ESAs) (n = 43) for 24 weeks. The primary end points were the mean hemoglobin (Hb) level at week 24, the change in average Hb levels from baseline to week 24, and the cumulative response rate throughout the treatment period. The secondary end points included changes in hepcidin and iron indices and serum lipid levels. Subgroup analysis examined the effect of inflammatory status on the efficacy of Hb. Safety was assessed as the occurrence of emergent adverse events after treatment.

RESULTS

The mean average Hb levels at week 24 and average change in Hb levels from baseline to week 24 were 11.5 g/dL and 2.5 g/dL in the roxadustat group and 11.2 g/dL and 2.2 g/dL in the ESAs group, respectively. The cumulative response rate was 96% in the roxadustat group and 92% in the ESAs group at week 24. Roxadustat decreased hepcidin levels and increased total iron-binding capacity. The decreases in total cholesterol and low-density lipoprotein cholesterol were greater with roxadustat than with ESAs. Roxadustat-induced Hb increases were independent of baseline C-reactive protein levels. Common adverse events included hyperkalemia, hypertension, and insomnia.

CONCLUSION

Roxadustat effectively corrected and maintained target Hb levels in Chinese PD patients. This trial was registered in the Chinese Clinical Trial Register (ChiCTR2000035054).

Role of Iron in the Molecular Pathogenesis of Diseases and Therapeutic Opportunities

Iron is an essential mineral that serves as a prosthetic group for a variety of proteins involved in vital cellular processes. The iron economy within humans is highly conserved in that there is no proper iron excretion pathway. Therefore, iron homeostasis is highly evolved to coordinate iron acquisition, storage, transport, and recycling efficiently. A disturbance in this state can result in excess iron burden in which an ensuing iron-mediated generation of reactive oxygen species imparts widespread oxidative damage to proteins, lipids, and DNA. On the contrary, problems in iron deficiency either due to genetic or nutritional causes can lead to a number of iron deficiency disorders. Iron chelation strategies have been in the works since the early 1900s, and they still remain the most viable therapeutic approach to mitigate the toxic side effects of excess iron. Intense investigations on improving the efficacy of chelation strategies while being well tolerated and accepted by patients have been a particular focus for many researchers over the past 30 years. Moreover, recent advances in our understanding on the role of iron in the pathogenesis of different diseases (both in iron overload and iron deficiency conditions) motivate the need to develop new therapeutics. We summarized recent investigations into the role of iron in health and disease conditions, iron chelation, and iron delivery strategies. Information regarding small molecule as well as macromolecular approaches and how they are employed within different disease pathogenesis such as primary and secondary iron overload diseases, cancer, diabetes, neurodegenerative diseases, infections, and in iron deficiency is provided.

Controversies in optimal anemia management: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Conference

In chronic kidney disease, anemia and disordered iron homeostasis are prevalent and associated with significant adverse consequences. In 2012, Kidney Disease: Improving Global Outcomes (KDIGO) issued an anemia guideline for managing the diagnosis, evaluation, and treatment of anemia in chronic kidney disease. Since then, new data have accrued from basic research, epidemiological studies, and randomized trials that warrant a re-examination of previous recommendations. Therefore, in 2019, KDIGO decided to convene 2 Controversies Conferences to review the latest evidence, explore new and ongoing controversies, assess change implications for the current KDIGO anemia guideline, and propose a research agenda. The first conference, described here, focused mainly on iron-related issues, including the contribution of disordered iron homeostasis to the anemia of chronic kidney disease, diagnostic challenges, available and emerging iron therapies, treatment targets, and patient outcomes. The second conference will discuss issues more specifically related to erythropoiesis-stimulating agents, including epoetins, and hypoxia-inducible factor-prolyl hydroxylase inhibitors. Here we provide a concise overview of the consensus points and controversies resulting from the first conference and prioritize key questions that need to be answered by future research.

Iron Sucrose: A Double-Edged Sword in High Phosphate Media-Induced Vascular Calcification

The high incidence of vascular calcification (VC) in patients with chronic kidney disease (CKD) has become an important clinical subject. Hyperphosphatemia is a primary cause of CKD-related VC. Intravenous iron sucrose (IS) is commonly used to treat anemia in CKD patients, and is effective and well tolerated worldwide. However, the interaction between iron and VC remains controversial, and the underlying mechanisms are yet to be clarified. In the present study, ex vivo normal rat aortic rings were cultured with various concentrations of phosphate and IS, and the levels of calcium and iron depositions, oxidative injury, as well as phenotypic marker genes were detected. To the best of our knowledge, the present study is the first to report that IS is a double-edged sword in high phosphate media-induced VC which not only alleviates VC in a dose-dependent manner but also leads to iron overload in vasculature when in high concentration. IS is a promising agent for VC prevention in patients with hyperphosphatemia and iron deficiency. Meanwhile, the appropriate blood concentration of IS in patients with hyperphosphatemia needs to be explored clinically.

Physiological and pathophysiological mechanisms of hepcidin regulation: clinical implications for iron disorders

The discovery of hepcidin has provided a solid foundation for understanding the mechanisms of systemic iron homeostasis and the aetiologies of iron disorders. Hepcidin assures the balance of circulating and stored iron levels for multiple physiological processes including oxygen transport and erythropoiesis, while limiting the toxicity of excess iron. The liver is the major site where regulatory signals from iron, erythropoietic drive and inflammation are integrated to control hepcidin production. Pathologically, hepcidin dysregulation by genetic inactivation, ineffective erythropoiesis, or inflammation leads to diseases of iron deficiency or overload such as iron-refractory iron-deficiency anaemia, anaemia of inflammation, iron-loading anaemias and hereditary haemochromatosis. In the present review, we discuss recent insights into the molecular mechanisms governing hepcidin regulation, how these pathways are disrupted in iron disorders, and how this knowledge is being used to develop novel diagnostic and therapeutic strategies.

Newer formulations of intravenous iron: a review of their chemistry and key safety aspects - hypersensitivity, hypophosphatemia, and cardiovascular safety

Introduction: The newest intravenous (IV) iron products show an improved safety profile over predecessors, allowing for the rapid administration of relatively high doses. Ferric derisomaltose (FDI; also known as iron isomaltoside), ferric carboxymaltose (FCM), and ferumoxytol (FER), are successful treatments for iron deficiency (Europe; FDI and FCM) and iron deficiency anemia (US; FDI, FCM, and FER).Areas covered: This review focusses on the chemistry and structure of FDI, FCM, and FER, and on three key aspects of IV iron safety: (1) hypersensitivity; (2) hypophosphatemia and sequelae; (3) cardiovascular safety.Expert opinion: Although the safety of modern IV iron has improved, immediate infusion reactions and the development of hypophosphatemia must be appreciated and recognized by those who prescribe and administer IV iron. Immediate infusion reactions can occur with any IV iron and are usually mild; severe reactions - particularly anaphylaxis - are extremely rare. The recognition and appropriate management of infusion reactions is an important consideration to the successful administration of IV iron. Severe, persistent, hypophosphatemia is a specific side effect of FCM. No cardiovascular safety signal has been identified for IV iron. Ongoing trials in heart failure will provide additional long-term efficacy and safety data.

Mitochondrial Reactive Oxygen Species and Their Contribution in Chronic Kidney Disease Progression Through Oxidative Stress

Mitochondria are known to generate approximately 90% of cellular reactive oxygen species (ROS). The imbalance between mitochondrial reactive oxygen species (mtROS) production and removal due to overproduction of ROS and/or decreased antioxidants defense activity results in oxidative stress (OS), which leads to oxidative damage that affects several cellular components such as lipids, DNA, and proteins. Since the kidney is a highly energetic organ, it is more vulnerable to damage caused by OS and thus its contribution to the development and progression of chronic kidney disease (CKD). This article aims to review the contribution of mtROS and OS to CKD progression and kidney function deterioration.

In-depth review: is hepcidin a marker for the heart and the kidney?

Iron is an essential trace element involved in oxidation-reduction reactions, oxygen transport and storage, and energy metabolism. Iron in excess can be toxic for cells, since iron produces reactive oxygen species and is important for survival of pathogenic microbes. There is a fine-tuning in the regulation of serum iron levels, determined by intestinal absorption, macrophage iron recycling, and mobilization of hepatocyte stores versus iron utilization, primarily by erythroid cells in the bone marrow. Hepcidin is the major regulatory hormone of systemic iron homeostasis and is upregulated during inflammation. Hepcidin metabolism is altered in chronic kidney disease. Ferroportin is an iron export protein and mediates iron release into the circulation from duodenal enterocytes, splenic reticuloendothelial macrophages, and hepatocytes. Systemic iron homeostasis is controlled by the hepcidin-ferroportin axis at the sites of iron entry into the circulation. Hepcidin binds to ferroportin, induces its internalization and intracellular degradation, and thus inhibits iron absorption from enterocytes, and iron release from macrophages and hepatocytes. Recent data suggest that hepcidin, by slowing or preventing the mobilization of iron from macrophages, may promote atherosclerosis and may be associated with increased cardiovascular disease risk. This article reviews the current data regarding the molecular and cellular pathways of systemic and autocrine hepcidin production and seeks the answer to the question whether changes in hepcidin translate into clinical outcomes of all-cause and cardiovascular mortality, and cardiovascular and renal end-points.

Low serum iron is associated with anemia in CKD stage 1-4 patients with normal transferrin saturations

Low transferrin saturation (TSAT), calculated by serum iron divided by total iron-binding capacity (TIBC), indicates iron deficiency. Because malnutrition and inflammation are associated with low TIBC in chronic kidney disease (CKD), TSAT might not reflect iron status or risk for anemia. We examined whether low serum iron was a risk factor for anemia in CKD patients with normal TSAT. Thus we compare the risk for anemia in 2500 CKD stage 1–4 patients divided by TSAT (cutoff: 20%) and serum iron (cutoff: 70 μg/dL in men, 60 μg/dL in women). Our results confirmed low TIBC (< 200 μg/dL) was associated with hypoalbuminemia and high C-reactive protein. In fully-adjusted logistic regression, both “normal TSAT low iron” and “low TSAT low iron” groups were associated with baseline anemia (hemoglobin < 11 g/dL) (odds ratios (OR) 1.56; 95% confidence interval (CI) 1.13–2.16 and OR 2.36; 95% CI 1.76–3.18, respectively) compared with the reference group (normal TSAT normal iron). Sensitivity tests with different cutoffs for TSAT and iron also showed similar results. In patients without anemia, both groups were associated with anemia after 1 year (OR 1.69; 95% CI 1.00–2.83 and OR 1.94; 95% CI 1.11–3.40, respectively). In conclusion, CKD stage 1–4 patients with normal TSAT but low serum iron are still at risk for anemia.

Assessment of positive iron balance in end-stage renal disease: Could hepcidin-25 be useful?

INTRODUCTION

The aim of our study was to examine the relationship of hepcidin-25 with red blood cell and reticulocyte indices and to evaluate the diagnostic properties of hepcidin-25 in the assessment of positive iron balance in end-stage renal disease (ESRD) patients.

METHODS

Eighty anemic ESRD patients (hemoglobin < 110 g/L) were classified as having iron deficiency (ID, N = 20), iron sufficiency (IS, N = 29), and positive iron balance (PB, N = 31) using the conventional biomarkers for iron status evaluation. Hepcidin-25 was determined by a chemiluminescent direct ELISA.

RESULTS

Hepcidin-25 was significantly negatively correlated with the proportion of hypochromic erythrocytes (%HYPO) (P = .034) and immature reticulocyte fraction (P = .010) in ID and with the absolute reticulocyte concentration in ID (P = .048) and PB (P = .040). In multivariate models, hepcidin-25 was independently negatively associated with the mean reticulocyte hemoglobin content (CHr; β = -0.493, P = .004) and red blood cell size factor (RSf) (β = -0.334, P = .036) only in the PB group. The best hepcidin-25 value to exclude PB was 66.13 µg/L, showing a sensitivity of 61.3%, a specificity of 75.5%, and an AUC of 0.808.

CONCLUSION

Our results suggest that hepcidin-25 levels are independently negatively associated with the iron demand for the most recent erythropoiesis only in PB. Hepcidin-25 performed acceptable in discriminating anemic ESRD patients with positive iron balance and may prove to be a useful additional tool in the evaluation of iron status.

Iron metabolism and management: focus on chronic kidney disease

Anemia is common in patients with chronic kidney disease (CKD) and results from the dysregulation of iron metabolism and erythropoiesis. Hepcidin is a key regulator of iron availability and leads to iron sequestration during the state of iron repletion. Decreases in the level of hepcidin in the presence of hypoxia and/or iron limitation allow for greater iron availability for erythropoiesis. However, kidney excretion of hepcidin decreases as the severity of CKD increases, whereas production of hepcidin is increased under inflammatory conditions often present in patients with CKD, both of which contribute to anemia. Assessment of iron status is, therefore, essential in the treatment of anemia. However, current laboratory tests for the determination of the adequate supply of iron have many limitations, including diurnal variation in the levels of biomarkers, lack of standardized reference methods across laboratories, and confounding by the presence of inflammation. In addition, the current treatment paradigm for anemia of CKD can further disrupt iron homeostasis; for example, treatment with erythropoiesis-stimulating agents in the absence of supplemental iron can induce functional iron deficiency. Moreover, supplemental iron can further increase levels of hepcidin. Several novel therapies, including hypoxia-inducible factor prolyl hydroxylase inhibitors and hepcidin inhibitors/antagonists, have shown promise in attenuating the levels and/or activity of hepcidin in anemia of CKD, thus ensuring the availability of iron for erythropoiesis.

A multicentre prospective double blinded randomised controlled trial of intravenous iron (ferric Derisomaltose (FDI)) in Iron deficient but not anaemic patients with chronic kidney disease on functional status

BACKGROUND

Iron deficiency (ID) is common in patients with chronic kidney disease (CKD). Intravenous (IV) iron in heart failure leads to improvement in exercise capacity and improvement in quality-of-life measurements; however, data in patients with CKD are lacking.

METHODS

The Iron and the Heart Study was a prospective double blinded randomised study in non-anaemic CKD stages 3b-5 patients with ID which investigated whether 1000 mg of IV iron (ferric derisomaltose (FDI)) could improve exercise capacity in comparison to placebo measured at 1 and 3 months post infusion. Secondary objectives included effects on haematinic profiles and haemoglobin, safety analysis and quality of life questionnaires (QoL).

RESULTS

We randomly assigned 54 patients mean (SD) age for FDI (n = 26) 61.6 (10.1) years vs placebo (n = 28; 57.8 (12.9) years) and mean eGFR (33.2 (9.3) vs. 29.1 (9.6) ml/min/1.73m2) at baseline, respectively. Adjusting for baseline measurements, six-minute walk test (6MWT) showed no statistically significant difference between arms at 1 month (p = 0.736), or 3 months (p = 0.741). There were non-significant increases in 6MWT from baseline to 1 and 3 months in the FDI arm. Haemoglobin (Hb) at 1 and 3 months remained stable. There were statistically significant increases in ferritin (SF) and transferrin saturation (TSAT) at 1 and 3 months (p < 0.001). There was a modest numerical improvement in QoL parameters. There were no adverse events attributable to IV iron.

CONCLUSION

This study demonstrated a short-term beneficial effect of FDI on exercise capacity, but it was not significant despite improvements in parameters of iron status, maintenance of Hb concentration, and numerical increases in functional capacity and quality of life scores. A larger study will be required to confirm if intravenous iron is beneficial in iron deficient non-anaemic non-dialysis CKD patients without heart failure to improve the 6MWT.

TRIAL REGISTRATION

European Clinical Trials Database (EudraCT) No: 2014-004133-16 REC no: 14/YH/1209 Date First Registered: 2015-02-17 and date of end of trail 2015-05-23 Sponsor ref R1766 and Protocol No: IHI 141.

A fully human anti-BMP6 antibody reduces the need for erythropoietin in rodent models of the anemia of chronic disease

Recombinant erythropoietin (EPO) and iron substitution are a standard of care for treatment of anemias associated with chronic inflammation, including anemia of chronic kidney disease. A black box warning for EPO therapy and concerns about negative side effects related to high-dose iron supplementation as well as the significant proportion of patients becoming EPO resistant over time explains the medical need to define novel strategies to ameliorate anemia of chronic disease (ACD). As hepcidin is central to the iron-restrictive phenotype in ACD, therapeutic approaches targeting hepcidin were recently developed. We herein report the therapeutic effects of a fully human anti-BMP6 antibody (KY1070) either as monotherapy or in combination with Darbepoetin alfa on iron metabolism and anemia resolution in 2 different, well-established, and clinically relevant rodent models of ACD. In addition to counteracting hepcidin-driven iron limitation for erythropoiesis, we found that the combination of KY1070 and recombinant human EPO improved the erythroid response compared with either monotherapy in a qualitative and quantitative manner. Consequently, the combination of KY1070 and Darbepoetin alfa resulted in an EPO-sparing effect. Moreover, we found that suppression of hepcidin via KY1070 modulates ferroportin expression on erythroid precursor cells, thereby lowering potentially toxic-free intracellular iron levels and by accelerating erythroid output as reflected by increased maturation of erythrocyte progenitors. In summary, we conclude that treatment of ACD, as a highly complex disease, becomes more effective by a multifactorial therapeutic approach upon mobilization of endogenous iron deposits and stimulation of erythropoiesis.

Iron replacement therapy in the management of anaemia in non-dialysis Chronic kidney disease patients: Perspective of the Spanish Nephrology Society Anaemia Group

This work presents an update on the management of iron deficiency in patients with chronic kidney disease (CKD), either with or without anaemia. A review is made of the recommendations of the guidelines for the treatment of iron deficiency in CKD. It also presents new studies on iron deficiency in patients with CKD, as well as new findings about iron therapy and its impact on clinical outcomes. Anaemia is a common complication of CRF, and is associated with a decrease in the quality of life of the patients, as well as an increase in morbidity and mortality. Iron deficiency (absolute or functional) is common in non-dialysis chronic kidney disease patients, and may cause anaemia or a low response to erythropoiesis-stimulating agents. For this reason, the clinical guidelines for the treatment of the anaemia in Nephrology indicate the correction of the deficiency in the presence of anaemia. Iron replacement therapy is indicated in patients with CKD and anaemia (Hb < 12 g/dl) in accordance with the guidelines. There is no unanimity in the indication of iron replacement therapy in patients with Hb > 12 g/dl, regardless of whether they have an absolute or functional iron deficiency. Intravenous iron replacement therapy is safe, more efficient and rapid than oral therapy for achieving an increase haemoglobin lels and reducing the dose of erythropoiesis-stimulating agents. For the administration of intravenous iron in non-dialysis chronic renal failure patients a strategy of high doses and low frequency would be preferred on being more convenient for the patient, preserves better the venous capital, and is safe and cost-effective. Iron plays an essential role in energy metabolism and other body functions beyond the synthesis of haemoglobin, for which the iron deficiency, even in the absence of anaemia, could have harmful effects in patients with CKD. The correction of the iron deficiency, in the absence of anaemia is associated with functional improvement in patients with heart failure, and in muscle function or fatigue in patients without CKD. Despite the evidence of benefits in the correction of iron deficiency in patients with CKD, more studies are required to evaluate the impact of the correction of the iron deficiency in the absence of anaemia on morbidity and mortality, quality of life and physical capacity, as well as the long-term effect of oral and intravenous iron replacement therapy in this population.

Hypophosphataemia, fibroblast growth factor 23 and third-generation intravenous iron compounds: a narrative review

Third-generation intravenous (i.v.) iron preparations are safe and efficacious and are increasingly used in the treatment of iron-deficiency anaemia. Hypophosphataemia is emerging as an established side-effect following the administration of certain compounds. Symptoms of hypophosphataemia can be masked by their similarity to those of iron-deficiency anaemia and both acute and chronic hypophosphataemia can be detrimental. Hypophosphataemia appears to be linked to imbalances in the metabolism of the phosphatonin fibroblast growth factor 23. In this narrative review, we discuss the possible pathophysiology behind this phenomenon, the studies comparing third-generation i.v. iron compounds, and the potential implications of the changes in fibroblast growth factor 23 and hypophosphataemia. We also present an algorithm of how to approach such patients requiring i.v. iron in anticipation of hypophosphataemia and how the impact related to it can be minimized.

Narrative Review of Hyperferritinemia, Iron Deficiency, and the Challenges of Managing Anemia in Aboriginal and Torres Strait Islander Australians With CKD

Aboriginal and Torres Strait Islander Australians (Indigenous Australians) suffer some of the highest rates of chronic kidney disease (CKD) in the world. Among Indigenous Australians in remote areas of the Northern Territory, prevalence rates for renal replacement therapy (RRT) are up to 30 times higher than national prevalence. Anemia among patients with CKD is a common complication. Iron deficiency is one of the major causes. Iron deficiency is also one of the key causes of poor response to the mainstay of anemia therapy with erythropoiesis-stimulating agents (ESAs). Therefore, the effective management of anemia in people with CKD is largely dependent on effective identification and correction of iron deficiency. The current identification of iron deficiency in routine clinical practice is dependent on 2 surrogate markers of iron status: serum ferritin concentration and transferrin saturation (TSAT). However, questions exist regarding the use of serum ferritin concentration in people with CKD because it is an acute-phase reactant that can be raised in the context of acute and chronic inflammation. Serum ferritin concentration among Indigenous Australians receiving RRT is often markedly elevated and falls outside reference ranges within most national and international guidelines for iron therapy for people with CKD. This review explores published data on the challenges of managing anemia in Indigenous people with CKD and the need for future research on the efficacy and safety of treatment of anemia of CKD in patients with high ferritin and evidence iron deficiency.

Factors associated with hepcidin-25 levels in maintenance hemodialysis patients

This study aimed to investigate the factors that are independently associated with hepcidin-25 and its relationship with doses of erythropoiesis-stimulating agents (ESAs) and intravenous iron in stable maintenance hemodialysis patients (smHD) stratified by ESAs administration. In 103 adult smHD (ESAs therapy (N = 64) and ESAs-free (N = 39)), median values of biologically active hepcidin-25 (chemiluminescent direct ELISA assay) and ferritin levels were significantly higher whereas red blood cell count, hemoglobin, and hematocrit values were lower in ESAs therapy compared to ESAs-free group (P < .001, for all). Our results suggest that ESAs-independent smHD exhibit supposedly normal hepcidin-25 levels and preserved iron homeostasis, with a lower degree of anemia. The results of our multivariable model indicate that hepcidin-25 levels are independently and positively associated with iron stores and inflammation, and inversely with active erythropoiesis, regardless of ESAs administration. Maintenance ESAs and the intravenous iron dose were not related to hepcidin-25 levels.

Burden of Anemia in Chronic Kidney Disease: Beyond Erythropoietin

Anemia is a frequent comorbidity of chronic kidney disease (CKD) and is associated with a considerable burden because of decreased patient health-related quality of life and increased healthcare resource utilization. Based on observational data, anemia is associated with an increased risk of CKD progression, cardiovascular events, and all-cause mortality. The current standard of care includes oral or intravenous iron supplementation, erythropoiesis-stimulating agents, and red blood cell transfusion. However, each of these therapies has its own set of population-specific patient concerns, including increased risk of cardiovascular disease, thrombosis, and mortality. Patients receiving dialysis or those who have concurrent diabetes or high blood pressure may be at greater risk of developing these complications. In particular, treatment with high doses of erythropoiesis-stimulating agents has been associated with increased rates of hospitalization, cardiovascular events, and mortality. Resistance to erythropoiesis-stimulating agents remains a therapeutic challenge in a subset of patients. Hypoxia-inducible factor transcription factors, which regulate several genes involved in erythropoiesis and iron metabolism, can be stabilized by a new class of drugs that act as inhibitors of hypoxia-inducible factor prolyl-hydroxylase enzymes to promote erythropoiesis and elevate hemoglobin levels. Here, we review the burden of anemia of chronic kidney disease, the shortcomings of current standard of care, and the potential practical advantages of hypoxia-inducible factor prolyl-hydroxylase inhibitors in the treatment of patients with anemia of CKD.