Proteinuria induced by parenteral iron in chronic kidney disease--a comparative randomized controlled trial

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.

Liposomal iron in moderate chronic kidney disease

INTRODUCTION AND OBJECTIVE

The optimal iron supplementation route of administration (intravenous vs oral) in patients with chronic kidney disease (CKD) not on dialysis is a hot topic of debate. An oral preparation (liposomal iron, FeSu) has recently been developed with high bioavailability and low incidence of side effects. The objective was to evaluate the efficacy of FeSu in patients with stage 3 CKD and gastrointestinal intolerance to conventional oral iron therapy.

MATERIAL AND METHODS

Prospective observational study of patients with stable stage 3 CKD and gastrointestinal intolerance to conventional oral iron therapy. An oral 30mg/day dose of FeSu was administered for 12 months. The primary outcome measure was haemoglobin increase at 6 and 12 months. Treatment adherence and adverse effects were also evaluated.

RESULTS

37 patients aged 72.6±14.7 years and with an estimated glomerular filtration rate (eGFR) of 42±10ml/min/1.73m² were included. 32 patients had received previous treatment with conventional oral formulations, 73% of which exhibited gastrointestinal intolerance with treatment adherence of 9.4%. After 6 months with FeSu, an increase in haemoglobin was observed versus baseline, which was sustained at 12 months (0.49±0.19 and 0.36±0.19g/dl, respectively, P<.05), despite a significant eGFR decrease of 3.16±1.16 and 4.20±1.28ml/min/1.73 m² at 6 and 12 months, respectively. None of the patients experienced adverse reactions that required the treatment to be suspended. Adherence was 100% at both 6 and 12 months.

CONCLUSIONS

FeSu is effective in a cohort of patients with stage 3 CKD with similar characteristics to the general population of moderate CKD patients, with a low rate of adverse reactions and excellent tolerability.

Impact of Intravenous Iron on Oxidative Stress and Mitochondrial Function in Experimental Chronic Kidney Disease

Background: Mitochondrial dysfunction is observed in chronic kidney disease (CKD). Iron deficiency anaemia (IDA), a common complication in CKD, is associated with poor clinical outcomes affecting mitochondrial function and exacerbating oxidative stress. Intravenous (iv) iron, that is used to treat anaemia, may lead to acute systemic oxidative stress. This study evaluated the impact of iv iron on mitochondrial function and oxidative stress. Methods: Uraemia was induced surgically in male Sprague-Dawley rats and studies were carried out 12 weeks later in two groups sham operated and uraemic (5/6 nephrectomy) rats not exposed to i.v. iron versus sham operated and uraemic rats with iv iron. Results: Induction of uraemia resulted in reduced iron availability (serum iron: 31.1 ± 1.8 versus 46.4 ± 1.4 µM), low total iron binding capacity (26.4 ± 0.7 versus 29.5 ± 0.8 µM), anaemia (haematocrit: 42.5 ± 3.0 versus 55.0 ± 3.0%), cardiac hypertrophy, reduced systemic glutathione peroxidase activity (1.12 ± 0.11 versus 1.48 ± 0.12 U/mL), tissue oxidative stress (oxidised glutathione: 0.50 ± 0.03 versus 0.36 ± 0.04 nmol/mg of tissue), renal mitochondrial dysfunction (proton/electron leak: 61.8 ± 8.0 versus 22.7 ± 5.77) and complex I respiration (134.6 ± 31.4 versus 267.6 ± 26.4 pmol/min/µg). Iron therapy had no effect on renal function and cardiac hypertrophy but improved anaemia and systemic glutathione peroxidase (GPx) activity. There was increased renal iron content and complex II and complex IV dysfunction. Conclusion: Iron therapy improved iron deficiency anaemia in CKD without significant impact on renal function or oxidant status.

Renal function in patients with non-dialysis chronic kidney disease receiving intravenous ferric carboxymaltose: an analysis of the randomized FIND-CKD trial

Background

Preclinical studies demonstrate renal proximal tubular injury after administration of some intravenous iron preparations but clinical data on renal effects of intravenous iron are sparse.

Methods

FIND-CKD was a 56-week, randomized, open-label, multicenter study in which patients with non-dialysis dependent chronic kidney disease (ND-CKD), anemia and iron deficiency without erythropoiesis-stimulating agent therapy received intravenous ferric carboxymaltose (FCM), targeting either higher (400–600 μg/L) or lower (100–200 μg/L) ferritin values, or oral iron.

Results

Mean (SD) eGFR at baseline was 34.9 (11.3), 32.8 (10.8) and 34.2 (12.3) mL/min/1.73 m² in the high ferritin FCM (n = 97), low ferritin FCM (n = 89) and oral iron (n = 167) groups, respectively. Corresponding values at month 12 were 35.6 (13.8), 32.1 (12.7) and 33.4 (14.5) mL/min/1.73 m². The pre-specified endpoint of mean (SE) change in eGFR from baseline to month 12 was +0.7 (0.9) mL/min/1.73 m² with high ferritin FCM (p = 0.15 versus oral iron), -0.9 (0.9) mL/min/1.73 m² with low ferritin FCM (p = 0.99 versus oral iron) and -0.9 (0.7) mL/min/1.73 m² with oral iron. No significant association was detected between quartiles of FCM dose, change in ferritin or change in TSAT versus change in eGFR. Dialysis initiation was similar between groups. Renal adverse events were rare, with no indication of between-group differences.

Conclusion

Intravenous FCM at doses that maintained ferritin levels of 100–200 μg/L or 400–600 μg/L did not negatively impact renal function (eGFR) in patients with ND-CKD over 12 months versus oral iron, and eGFR remained stable. These findings show no evidence of renal toxicity following intravenous FCM over a 1-year period.

Trial registrations

ClinicalTrials.gov NCT00994318 (first registration 12 October 2009).

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0444-6) contains supplementary material, which is available to authorized users.

Lipids, blood pressure and kidney update 2015

The most important studies and guidelines in the topics of lipid, blood pressure and kidney published in 2015 were reviewed. In lipid research, the IMProved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT) trial revalidated the concept "lower is better" for low density lipoprotein (LDL)-cholesterol as a target for therapy, increasing the necessity of treatment the high-risk patients to achieve LDL-C goals. After these results, ezetimibe might become the preferred additional drug in the combination therapy of lipid disorders because of oral dosage form and lower acquisition cost. However, for the statin-intolerant patients and those patients requiring essential reductions in LDL-C to achieve their goals, new therapies, including PCSK9 inhibitors remain promising drugs. In blood pressure research, American Heart Association (AHA)/American College of Cardiology (ACC) 2015 guidelines recommended a target for blood pressure below 140/90 mmHg in stable or unstable coronary artery disease patients and below 150/90 mmHg in patients older than 80 years of age, however the recent results of the Systolic Blood Pressure Intervention Trial (SPRINT) trial have suggested that there might be significant benefits, taking into account cardiovascular risk, for hypertensive patients over 50 without diabetes and blood pressure levels <120/80. In kidney research, reducing the progression of chronic kidney disease and related complications such as anemia, metabolic acidosis, bone and mineral diseases, acute kidney injury and cardiovascular disease is still a goal for clinicians.

A randomized trial of intravenous and oral iron in chronic kidney disease

Although iron is commonly used to correct iron deficiency anemia (IDA) in chronic kidney disease (CKD) its effect on kidney function is unclear. To assess this, we randomly assigned patients with Stage 3 and 4 CKD and IDA to either open-label oral ferrous sulfate (69 patients to 325 mg three times daily for 8 weeks) or intravenous iron sucrose (67 patients to 200 mg every 2 weeks, total 1 gram). The primary outcome was the between group difference in slope of measured glomerular filtration rate (mGFR) change over two years. The trial was terminated early on the recommendation of an independent Data and Safety Monitoring Board based on little chance of finding differences in mGFR slopes, but a higher risk of serious adverse events in the intravenous iron treatment group. mGFR declined similarly over two years in both treatment groups (oral −3.6 mL/min/1.73m², intravenous − 4.0 mL/min/1.73m², between group difference − 0.35 mL/min/1.73m² (95% confidence interval −2.9 to 2.3). There were 36 serious cardiovascular events among 19 participants assigned to the oral iron treatment group and 55 events among 17 participants of the intravenous iron group (adjusted incidence rate ratio 2.51 (1.56−4.04). Infections resulting in hospitalizations had a significant adjusted incidence rate ratio of 2.12 (1.24−3.64). Thus, among non-dialyzed patients with CKD and IDA, intravenous iron therapy is associated with an increased risk of serious adverse events, including those from cardiovascular causes and infectious diseases.

Iron supplementation associates with low mortality in pre-dialyzed advanced chronic kidney disease patients receiving erythropoiesis-stimulating agents: a nationwide database analysis

BACKGROUND

A risk/benefit analysis of iron supplementation in pre-dialysis advanced chronic kidney disease (CKD) patients has not been conducted. We aim to assess the effectiveness and the safety of iron supplementation in patients with CKD Stage 5 who have not yet received dialysis (CKD 5 ND).

METHODS

A prospective cohort study was conducted based on the Taiwan National Health Insurance Research Database. From 1 January 2000 to 30 June 2009, we enrolled 31 971 adult patients who had a serum creatinine >6 mg/dL and a haematocrit <28% and who were treated with erythropoiesis-stimulating agents (ESAs). All patients were further divided into two groups with or without iron supplementation within 90 days after starting ESA therapy. Patient follow-up took place until dialysis, death before initiation of dialysis or 31 December 2009. The primary outcomes were death before initiating dialysis, hospitalization before death or long-term dialysis.

RESULTS

After propensity score matching, the patients who received iron supplementation were associated with a lower risk of all-cause death [hazard ratio (HR), 0.85; 95% confidence interval (CI), 0.80-0.90] compared with non-users. The survival benefit of iron use was consistent across the majority of dosage groups, except for those who were treated with monthly IV iron >200 mg. Moreover, compared with the non-users, the iron users were associated with a lower risk of hospitalizations (HR, 0.97; 95% CI, 0.94-0.99) but with a higher risk of faster progression to end-stage renal disease (HR, 1.05; 95% CI, 1.01-1.08).

CONCLUSIONS

Iron supplementation is associated with 15% risk reduction in death among CKD 5 ND patients who received ESA treatment. Randomized studies are needed to validate this association.

Euvolemia in hemodialysis patients: a potentially dangerous goal?

Dialysis patients have high mortality rate and the leading cause of death is cardiovascular disease. Uremic cardiomyopathy differs from that due to conventional atherosclerosis, where cardiovascular changes result in ineffective circulation and lead to tissue ischemia. Modern dialysis has significant limitations with fluid management probably the most challenging. Current evidence suggests that both volume overload and aggressive fluid removal can induce circulatory stress and multi-organ injury. Furthermore, we do not have accurate volume assessment tools. As a result, targeting euvolemia might result in more harm than benefit with conventional hemodialysis therapy. Therefore, it might be time to consider a degree of permissive over-hydration until we have better tools to both determine ideal weight and improve current renal replacement therapy so that the process of achieving it is not so fraught with the current dangers.

The FIND-CKD study--a randomized controlled trial of intravenous iron versus oral iron in non-dialysis chronic kidney disease patients: background and rationale

Background

Rigorous data are sparse concerning the optimal route of administration and dosing strategy for iron therapy with or without concomitant erythropoiesis-stimulating agent (ESA) therapy for the management of iron deficiency anaemia in patients with non-dialysis dependent chronic kidney disease (ND-CKD).

Methods

FIND-CKD was a 56-week, open-label, multicentre, prospective, randomized three-arm study (NCT00994318) of 626 patients with ND-CKD and iron deficiency anaemia randomized to (i) intravenous (IV) ferric carboxymaltose (FCM) at an initial dose of 1000 mg iron with subsequent dosing as necessary to target a serum ferritin level of 400–600 µg/L (ii) IV FCM at an initial dose of 200 mg with subsequent dosing as necessary to target serum ferritin 100–200 µg/L or (iii) oral ferrous sulphate 200 mg iron/day. The primary end point was time to initiation of other anaemia management (ESA therapy, iron therapy other than study drug or blood transfusion) or a haemoglobin (Hb) trigger (two consecutive Hb values <10 g/dL without an increase of ≥0.5 g/dL).

Results

The background, rationale and study design of the trial are presented here. The study has been completed and results are expected in late 2013.

Discussion

FIND-CKD was the longest randomized trial of IV iron therapy to date. Its findings will address several unanswered questions regarding iron therapy to treat iron deficiency anaemia in patients with ND-CKD. It was also the first randomized trial to utilize both a high and low serum ferritin target range to adjust IV iron dosing, and the first not to employ Hb response as its primary end point.

Iron toxicity: relevance for dialysis patients

Iron deficiency is common among patients with advanced kidney disease, particularly those requiring hemodialysis. Intravenous iron is a convenient treatment to supplement iron and is widely used among hemodialysis patients. Its efficacy is well established that, with treatment, hemoglobin levels rise and erythropoiesis-stimulating agent dose requirements are reduced. However, the safety of intravenous iron with respect to patient-centered outcomes has not been adequately studied. A variety of studies have indicated potential safety concerns, but most have been of small numbers of patients and with end points studied that have unclear clinical relevance. In this study, issues related to iron toxicity are reviewed.

Ferumoxytol: a silver lining in the treatment of anemia of chronic kidney disease or another dark cloud?

Intravenous iron therapy is pivotal in the treatment of anemia of chronic kidney disease to optimize the response of hemoglobin to erythropoiesis-stimulating agents. Intravenous iron use in patients with chronic kidney disease is on the rise. Recent clinical trial data prompting safety concerns regarding the use of erythropoiesis-stimulating agents has stimulated new US Food and Drug Administration label changes and restrictions for these agents, and has encouraged more aggressive use of intravenous iron. The currently available intravenous iron products differ with regard to the stability of the iron-carbohydrate complex and potential to induce hypersensitivity reactions. Ferumoxytol is a newer large molecular weight intravenous iron formulation that is a colloidal iron oxide nanoparticle suspension coated with polyglucose sorbitol carboxymethyl ether. Ferumoxytol has robust iron-carbohydrate complex stability with minimal dissociation or appearance of free iron in the serum, allowing the drug to be given in relatively large doses with a rapid rate of administration. Clinical trials have demonstrated the superior efficacy of ferumoxytol versus oral iron with minimal adverse effects. However, recent postmarketing data have demonstrated a risk of hypersensitivity that has prompted new changes to the product information mandated by the Food and Drug Administration. Additionally, the long-term safety of this agent has not been evaluated, and its place in the treatment of anemia of chronic kidney disease has not been fully elucidated.

Efficacy and tolerability of accelerated-dose low-molecular-weight iron dextran (Cosmofer) in patients with chronic kidney disease

INTRODUCTION

The Renal NSF advocates correction of anaemia in chronic kidney disease patients. Oral iron is often insufficient, while intravenous supplementation replenishes and maintains iron stores. There is a need to administer high doses of iron in a single rapid infusion to enable efficient costs, effective utilisation of time for patients and staff and optimal use of resources.

METHODS

We performed a prospective study of consecutive patients referred for iron dextran (Cosmofer) therapy. This was administered over 2 h 40 min compared with the normal regime of 4-6 h. Blood pressure was recorded throughout administration. Adverse drug reactions were recorded over 2 weeks. Serum ferritin, haemoglobin and estimated glomerular filtration rate were measured at baseline and 3 months.

RESULTS

One hundred patients (59 male, mean age 69 years), received a median dose of 1,000 mg Cosmofer in a median time of 2 h 40 min. Mean serum ferritin rose from 178 at baseline to 413 μg/l (p < 0.001). Mean haemoglobin rose by 1.5 g/dl (p < 0.001). There was no decline in estimated glomerular filtration rate after 3 months. No adverse reactions were noted.

CONCLUSION

We demonstrated that accelerated administration of iron dextran is safe and effective with no short-term effects on renal function. This resulted in a time saving of approximately 67 hours.