When should iron supplementation in dialysis patients be avoided, minimized or withdrawn?

Cardiovascular and renal safety outcomes of hypoxia-inducible factor prolyl-hydroxylase inhibitor roxadustat for anemia patients with chronic kidney disease: a systematic review and meta-analysis

This systematic review and meta-analysis were conducted to evaluate the cardiac and kidney-related adverse effects of roxadustat for the treatment of anemia in CKD patients. 18 trials with a total of 8806 participants were identified for analysis. We employed a fixed-effects model for analysis. The pooled result revealed no significant difference in the risk of occurrence of cardiac disorders when comparing CKD patients receiving roxadustat with the placebo (RR = 1.049; CI [0.918 to 1.200]) or ESA (RR = 1.066; CI [0.919 to 1.235]), in both dialysis-dependent (DD) (RR = 1.094; CI [0.925 to 1.293]) or non-dialysis-dependent (NDD) (RR = 1.036; CI [0.916 to 1.171]) CKD patients. No significant difference was observed in the risk of kidney-related adverse events when comparing roxadustat with the placebo (RR = 1.088; CI [0.980 to 1.209]) or ESA (RR = 0.968; CI [0.831 to 1.152]), in DD (RR = 2.649; CI [0.201 to 34.981]) or NDD (RR = 1.053; CI [0.965 to 1.149]) CKD patients. A high risk of hyperkalemia was observed in the roxadustat group in DD (RR = 0.939; CI [0.898 to 0.981]). Incidence of hypertension was higher in the roxadustat for NDD patients (RR = 1.198; CI [1.042 to 1.377]), or compared to the placebo (RR = 1.374; CI [1.153 to 1.638]). In summary, the risk of cardiac or kidney-related events observed in the roxadustat was not significantly increase whether in DD or NDD patients. However, attention must be paid to the occurrence of hyperkalemia for DD patients and hypertension in NDD patients using roxadustat.

Comparative iron management in hemodialysis and peritoneal dialysis patients: a systematic review

Background

Patients with kidney failure undergoing dialysis often suffer from anemia. Iron deficiency, along with a shortage in erythropoietin, is a common cause. Peritoneal dialysis (PD) patients may have a different iron metabolism compared to hemodialysis (HD) patients. This study aims to compare both dialysis modalities regarding their differences in iron management.

Methods

PubMed (MEDLINE) and Embase were screened for randomized controlled trials and observational studies including both patients on HD or PD with information on iron management. Outcomes for iron management for this systematic review included: prevalence of supplementation, route of administration, dose, frequency and hemoglobin and iron status parameters.

Results

15 eligible studies (930,436 patients), of which 8 cohort and 7 cross-sectional, were analyzed. The prevalence of intravenous (IV) iron supplementation ranged from 11.7% to 84.4% in HD patients, compared to 1.6% to 49.0% in PD patients. Ten studies reported that HD patients only received IV iron, while five studies reported this for PD patients. For oral iron supplementation, three studies involved HD patients, whereas seven studies involved PD patients. The cumulative monthly IV iron dose ranged from 108 to 750 mg in the HD group, compared to 65 to 250 mg in the PD group. Hemoglobin levels ranged from 10.0 to 12.0 g/dL in HD patients, versus 9.6 to 11.9 g/dL in PD patients.

Conclusion

Iron management differs between HD and PD patients, with HD patients receiving higher doses and more frequent IV iron. There was significant heterogeneity in the outcomes between the studies, primarily due to the lack of a uniform global policy on iron management. Despite these differences, hemoglobin levels and iron status parameters were comparable between the two groups. Future research should explore the underlying mechanisms and broader impacts of iron treatment, including patient-reported outcomes, to optimize anemia management and improve quality of life for dialysis patients.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022336970.

Cut-off values of haemoglobin and clinical outcomes in incident peritoneal dialysis: the PDTAP study

BACKGROUND

To explore the cut-off values of haemoglobin (Hb) on adverse clinical outcomes in incident peritoneal dialysis (PD) patients based on a national-level database.

METHODS

The observational cohort study was from the Peritoneal Dialysis Telemedicine-assisted Platform (PDTAP) dataset. The primary outcomes were all-cause mortality, major adverse cardiovascular events (MACE) and modified MACE (MACE+). The secondary outcomes were the occurrences of hospitalization, first-episode peritonitis and permanent transfer to haemodialysis (HD).

RESULTS

A total of 2591 PD patients were enrolled between June 2016 and April 2019 and followed up until December 2020. Baseline and time-averaged Hb <100 g/l were associated with all-cause mortality, MACE, MACE+ and hospitalizations. After multivariable adjustments, only time-averaged Hb <100 g/l significantly predicted a higher risk for all-cause mortality {hazard ratio [HR] 1.83 [95% confidence interval (CI) 1.19-281], P = .006}, MACE [HR 1.99 (95% CI 1.16-3.40), P = .012] and MACE+ [HR 1.77 (95% CI 1.15-2.73), P = .010] in the total cohort. No associations between Hb and hospitalizations, transfer to HD and first-episode peritonitis were observed. Among patients with Hb ≥100 g/l at baseline, younger age, female, use of iron supplementation, lower values of serum albumin and renal Kt/V independently predicted the incidence of Hb <100 g/l during the follow-up.

CONCLUSION

This study provided real-world evidence on the cut-off value of Hb for predicting poorer outcomes through a nation-level prospective PD cohort.

Benefits and risks of essential trace elements in chronic kidney disease: a narrative review

Background and Objective

Chronic kidney disease (CKD) is an important public health concern. With the decline of renal function, CKD patients gradually progress to end-stage kidney disease and need to undergo dialysis or kidney transplantation to maintain life, bringing a heavy economic burden to the family and society. Therefore, it is necessary to effectively prevent and delay the progression of CKD. Essential trace elements play an indispensable role in CKD, and the objective of this study is to systematically review their benefits in the disease and summarize the risks of their excess.

Methods

The keywords "trace elements", "chronic kidney disease", "dialysis", "inflammation", and "fibrosis" and their combinations were used to search for relevant literature published in the PubMed database and Web of Science. We then summarized the role of trace element abnormalities in CKD patients in anemia, oxidative stress, inflammation, and chronic fibrosis, and the risk of their excess.

Key Content and Findings

Imbalance of essential trace elements is a common complication of CKD and a risk factor for CKD progression, cardiovascular events, and death. This article reviews the effects of essential trace elements (iron, zinc, selenium, copper, iodine, and manganese) on CKD. We analyze literature and discuss the advantages and disadvantages of various essential trace elements.

Conclusions

Research shows CKD patients have an imbalance of essential trace elements, and treatment based on these is an important direction for future exploration. A knowledge of the homeostasis of trace elements is important to improving the prognosis of CKD patients and delaying the progression of the disease.

Cardiovascular Protective Effects of Oral Hypoxia Inducible Factor Prolyl Hydroxylase Inhibitor Roxadustat in the Treatment of Type 4 Cardiorenal-Anemia Syndrome: Protocol of a Randomized Controlled Trial

Background

Patients with chronic kidney disease (CKD) are at high risk of developing heart failure and anemia, which is defined as type 4 cardiorenal-anemia syndrome (CRAS). CRAS aggravates the deterioration of both kidney and heart function, ultimately resulting in a high mortality. This study aims to examine the efficacy and safety of roxadustat in the treatment of type 4 CRAS.

Methods and Design

This study is designed as a randomized, open-label, controlled trial. A total of 68 patients diagnosed with type 4 CRAS will be randomly divided into roxadustat group and erythropoietin with a 1:1 ratio. Participants in the roxadustat group will receive roxadustat with an initial dose of 70 or 100 mg three times a week, and participants in the erythropoietin group will receive subcutaneous injection of erythropoietin for 24 weeks, to maintain a hemoglobin ranging from 100 to 120 g per liter. The primary outcome is the change in heart function, including brain natriuretic peptide (BNP), 6-min walk test (6-WT), and left ventricular ejection fraction (LVEF). Secondary outcomes to be assessed include death, cardiovascular events, hospitalization regarding heart failure, Minnesota Heart Failure Quality of life scale (MLHFQ) score, New York Heart Association (NYHA) cardiac function grade, echocardiographic parameters including left ventricular diastolic diameter and volume (LVDD and LVDV) and ventricular mass (LVM), anemia related parameters, inflammatory parameters, and safety assessments.

Conclusion

The findings of this study will provide potential evidence for roxadustat in CRAS management.

Trial Registration

Chinese Clinical Trial Registry, ID: ChiCTR2100050031. Registered on 16 August 2021.

Recent and Emerging Therapies for Iron Deficiency in Anemia of CKD: A Review

Iron deficiency commonly contributes to the anemia affecting individuals with chronic kidney disease. Diagnostic criteria for iron deficiency in chronic kidney disease are explained. Mechanisms of functional and absolute iron deficiency and general treatment Principles as delineated in the Kidney Disease: Improving Global Outcomes guidelines are reviewed. Repletion of absolute iron deficits has progressed over time with the addition of better tolerated, more effective oral agents including ferric citrate, ferric maltol, and sucrosomial iron. Structural characteristics and trial data enabling regulatory approval of these novel oral agents are examined. Newer intravenous iron therapies including ferric carboxymaltose and ferric derisomaltose allow for fewer infusions and decreased risk of serious hypersensitivity reactions. Concerns about adverse events including cardiovascular events and infections are discussed. The potential risk of 6H syndrome due to these intravenous agents, including hypophosphatemia, osteomalacia, and pathologic fractures is emphasized. The proposed pathophysiology of 6H syndrome and hypophosphatemia is described. Ferric pyrophosphate citrate enables administration of iron for repletion through dialysate. Relative merits, costs, and risks of various iron agents such as hypersensitivity and 6H syndrome/hypophosphatemia are summarized.

Anemia Management in Peritoneal Dialysis: Perspectives From the Asia Pacific Region

Anemia is an important complication in patients with chronic kidney disease. Peritoneal dialysis (PD) is one of the most common modalities of kidney replacement therapy for patients with end-stage kidney disease. PD is particularly prevalent in the Asian Pacific region. Among the different countries and regions, including mainland China, Hong Kong, Japan, Malaysia, Singapore, South Korea, and Thailand, PD accounts for 2.8% to 74.6% of the dialysis population. In addition, 82% to 96% of the PD populations from these countries and regions are receiving erythropoiesis-stimulating agents (ESAs). Asian Pacific countries and regions follow the latest KDIGO (Kidney Disease: Improving Global Outcomes) guidelines for the initiation of treatment of anemia in PD patients. The types of ESAs commonly used include shorter-acting (epoetin alfa and beta) and longer-acting agents, including darbepoetin alfa or methoxy polyethylene glycol-epoetin beta. The most commonly used ESAs in Mainland China, Malaysia, Singapore, and Thailand are the shorter-acting agents, whereas in Hong Kong, Japan, and South Korea, longer-acting ESAs are most common. Oral iron therapy is still the most commonly used iron supplement. The route and dosage of iron administration in PD patients requires more research studies. With the introduction of oral hypoxia-inducible factor prolyl hydroxylase inhibitors into clinical use, the landscape of treatment of anemia in the PD population in the Asia Pacific region may change in the coming years.

The potential role of Na-K-ATPase and its signaling in the development of anemia in chronic kidney disease

Chronic kidney disease (CKD) is one of the most prominent diseases affecting our population today. According to the Factsheet published by Centers for Disease Control and Prevention (CDC), it effects approximately 15% of the total population in the United States in some way, shape, or form. Within the myriad of symptomatology associated with CKD, one of the most prevalent factors in terms of affecting quality of life is anemia. Anemia of CKD cannot be completely attributed to one mechanism or cause, but rather has a multifactorial origin in the pathophysiology of CKD. While briefly summarizing well-documented risk factors, this review, as a hypothesis, aims to explore the possible role of Na-K-ATPase and its signaling function [especially recent identified reactive oxygen species (ROS) amplification function] in the interwoven mechanisms of development of the anemia of CKD.

Anaemia in patients undergoing major bowel surgery - Prevalence and current practice: A public and private institution experience

AIM

The study aimed to compare the frequency and alignment of preoperative anaemia screening and treatment with Australian guidelines in elective bowel surgery and determine the impact on clinical outcomes.

METHODS

We performed a retrospective observational study, with an audit of 559 adult patients who underwent major elective bowel surgery in an Australian metropolitan hospital, January 2016-December 2018. Outcome measures included rate of anaemia, guideline compliance, hospital length of stay, and transfusion rate.

RESULTS

Preoperative anaemia assessment occurred in 82.6% of patients. However, only 5.2% received recommended biochemical tests at least one week before surgery. Only 25.2% of anaemic patients received preoperative treatment; they experienced a longer hospital length of stay (9.93 days versus 7.88 days, p < 0.001) and an increased rate of transfusion (OR: 3.186, p < 0.05).

CONCLUSION

The gaps between current preoperative anaemia screening, management and national guidelines may place patients at higher risk of poor surgical outcome.

Hypoxia-inducible factor prolyl hydroxylase inhibitors: a paradigm shift for treatment of anemia in chronic kidney disease?

INTRODUCTION

The hypoxia-inducible factor prolyl hydroxylase (HIF-PH) pathway is responsible for regulating the biosynthesis of erythropoietin (EPO) and maintaining iron homeostasis. Investigational drugs that target the HIF-PH pathway are promising alternatives for treating anemia in Chronic Kidney Disease (CKD).

AREAS COVERED

This review summarizes recent advances focused on the clinical development of HIF-PH inhibitors (HIF-PHIs) as potentially novel therapies in the treatment of anemia in CKD based on publications available on PubMed and restricted Google searches. We provide a comparison between HIF-PHIs regarding their pharmacokinetics, dosing regimens and safety concerns, structure-activity relationships, and alterations in key laboratory parameters observed in animal models and clinical trials.

EXPERT OPINION

HIF-PHIs may be advantageous in some aspects compared to the conventional erythropoiesis-stimulating agents (ESAs). While ESAs could increase the risk of cardiovascular events due to rapid rises in ESA blood levels, HIF-PHIs have been reported to maintain EPO concentrations at levels that are closer to the normal physiological ranges. Although HIF-PHIs have been demonstrated to be relatively safe and effective in clinical trials, long-term safety data are needed in order to establish whether these therapeutic agents will lead to a major paradigm change in the treatment of anemia of CKD.

Molecular Mechanisms of Premature Aging in Hemodialysis: The Complex Interplay Between Innate and Adaptive Immune Dysfunction

Hemodialysis (HD) patient are known to be susceptible to a wide range of early and long-term complication such as chronic inflammation, infections, malnutrition, and cardiovascular disease that significantly affect the incidence of mortality. A large gap between the number of people with end-stage kidney disease (ESKD) and patients who received kidney transplantation has been identified. Therefore, there is a huge need to explore the underlying pathophysiology of HD complications in order to provide treatment guidelines. The immunological dysregulation, involving both the innate and adaptive response, plays a crucial role during the HD sessions and in chronic, maintenance treatments. Innate immune system mediators include the dysfunction of neutrophils, monocytes, and natural killer (NK) cells with signaling mediated by NOD-like receptor P3 (NLRP3) and Toll-like receptor 4 (TLR4); in addition, there is a significant activation of the complement system that is mediated by dialysis membrane-surfaces. These effectors induce a persistent, systemic, pro-inflammatory, and pro-coagulant milieu that has been described as inflammaging. The adaptive response, the imbalance in the CD4+/CD8+ T cell ratio, and the reduction of Th2 and regulatory T cells, together with an altered interaction with B lymphocyte by CD40/CD40L, have been mainly implicated in immune system dysfunction. Altogether, these observations suggest that intervention targeting the immune system in HD patients could improve morbidity and mortality. The purpose of this review is to expand our understanding on the role of immune dysfunction in both innate and adaptive response in patients undergoing hemodialysis treatment.

Status of malondialdehyde, catalase and superoxide dismutase levels/activities in schoolchildren with iron deficiency and iron-deficiency anemia of Kashere and its environs in Gombe State, Nigeria

Background

Iron-deficiency anemia (IDA) or iron deficiency (ID) is by far the most common form of disorder affecting the cognitive development, physical growth and school performance of children in developing countries including Nigeria.

Objectives

In the present study, we aimed to examine whether IDA or ID, or both are associated with oxidative stress or otherwise by assessing the perturbations in oxidative stress markers including malondialdehyde (MDA), catalase (CAT) and superoxide dismutase (SOD).

Methods

Here, a total of eighty-one IDA, ID, and healthy control subjects of twenty-seven replicates each, were recruited and investigated. Human serum MDA, CAT and SOD levels were quantitatively analyzed using Enzyme-Linked Immunosorbant Assay.

Results

Mean serum MDA levels of IDA (5.10 ± 2.35 mmol/L) and ID (4.05 ± 1.35 mmol/L) groups were found to perturb significantly (p < 0.05), being higher than those of control (3.30 ± 0.95 mmol/L) subjects. Similarly, mean serum MDA levels of IDA (5.10 ± 2.35 mmol/L) group was found to be significantly (p < 0.05) higher when compared with ID (4.05 ± 1.35 mmol/L) subjects. Conversely, mean serum CAT and SOD activities of IDA (8.35 ± 2.21 ng/mL and 340.70 ± 153.65 ng/mL) group were found to differ significantly (p < 0.05), and those of ID (9.40 ± 1.47 ng/mL and 435.00 ± 144.75 ng/mL) subjects were found to perturb slightly (p > 0.05), being lower than those of control (10.40 ± 4.31 ng/mL and 482.12 ± 258.37 ng/mL) subjects.

Conclusions

Taken together, the results of the present study showed that lipid peroxidation was dramatically increased in both IDA and ID subjects in hydroperoxide-superoxide-dependent manner; in contrast, enzymatic antioxidant capacity was drastically decreased in both IDA and ID groups as evidenced by biochemical markers.

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.

Hepcidin in chronic kidney disease anemia

Chronic kidney disease (CKD) is associated with several complications that worsen with progression of disease; anemia, disturbances in iron metabolism and inflammation are common features. Inflammatory response starts early, releasing pro-inflammatory cytokines, acute phase reactants and hepcidin. Hepcidin production is modulated by several factors, as hypoxia/anemia, erythropoietin and erythropoiesis products, transferrin saturation (TSAT) and liver iron levels, which are altered in CKD. Treatment of CKD anemia is based on pharmaceutical intervention, with erythropoietic stimulating agents and/or iron supplementation; however, in spite of the erythropoietic benefits, this therapy, on a regular basis, involves risks, namely iron overload. To overcome these risks, some therapeutic approaches are under study to target CKD anemia. Considering the actual alerts about risk of iron overload in dialysis patients, inhibition of hepcidin, the central key player in iron homeostasis, could be a pivotal strategy in the management of CKD anemia.

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.