Evaluating the effectiveness of IV iron dosing for anemia management in common clinical practice: results from the Dialysis Outcomes and Practice Patterns Study (DOPPS)

The anaemia treatment journey of CKD patients: from epoetins to hypoxia-inducible factor-prolyl hydroxylase inhibitors

The discovery and development of erythropoiesis-stimulating agents was a journey lasting more than a century, leading to the cloning and approval of recombinant human erythropoietin (rHuEpo). This was an impressive clinical advance, providing the possibility of correcting the symptoms associated with anaemia in chronic kidney disease. Associated iron use was needed to produce new haemoglobin-containing blood red cells. Partial anaemia correction became the standard of care since trials aiming for near-normal haemoglobin levels showed a higher risk of adverse cardiovascular events. Hoping to reduce the cardiovascular risks, a new category of drugs was developed and tested. Hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) are small molecules than can be formulated into orally active pills. They simulate reduced tissue oxygen pressure, thus stimulating the production of endogenous erythropoietin (Epo) by the kidneys and liver. Clinical trials with these compounds demonstrated that HIF-PHIs are at least as effective as rHuEpo in treating or correcting anaemia in non-dialysis and dialysis patients. Trials with HIF-PHIs did not demonstrate superiority in safety outcomes and in some trials, outcomes were worse. There was also a focus on oral delivery, a possible beneficial iron-sparing effect and the ability to overcome Epo resistance in inflamed patients. A negative effect is possible iron depletion, which may explain adverse outcomes.

The Association of Intravenous Iron Administered the Day before Total Knee Arthroplasty with Postoperative Anemia and Functional Recovery

Background and Objectives: Total knee arthroplasty (TKA) involves blood loss, increasing the risk of postoperative anemia and delayed functional recovery. Intravenous (IV) iron supplementation limits postoperative anemia; however, the effectiveness of IV iron, administered one day before TKA, on postoperative anemia and functional recovery has scarcely been studied. Materials and Methods: We conducted a retrospective cohort study with propensity score matching using two consecutive groups of patients who underwent TKA using tranexamic acid: the iron group received 500 mg ferric derisomaltose intravenously one day before surgery (n = 46); the non-iron group did not (n = 46). Hemoglobin (Hb) level was determined at postoperative days (PODs) 2, 4, 6, 14, and 30. Ferritin, transferrin saturation (TSAT), and functional iron deficiency anemia (IDA) rate were measured at PODs 2, 4, 6, and 14. Length of hospital stay and transfusion rate were also evaluated. Results: The iron group had higher Hb levels at PODs 6, 14, and 30 and higher ferritin and TSAT at PODs 2, 4, 6, and 14. The functional IDA rate was significantly higher in the non-iron group at PODs 2, 4, 6, and 14. Length of hospital stay was significantly shorter in the iron group; however, the rate of transfusion did not differ between the two groups. Conclusions: IV iron administered one day before TKA was associated with postoperative anemia recovery and length of hospital stay; however, it did not lower the postoperative transfusion rate.

Relation of Liver Siderosis to Liver Fibrosis in Hemodialysis Patients With Severe Hyperferritinemia Secondary to High Doses of Intravenous Iron Supplementation

OBJECTIVE

Aggressive iron substitution in hemodialysis (HD) patients leads to iron overload. The association between liver siderosis and fibrosis is still debatable. We studied the association of liver siderosis with liver fibrosis in HD patients. Furthermore, we studied the performance of liver stiffness measurements (LSMs) in identifying advanced liver fibrosis. We investigated the performance of biochemical indicators of iron status in identifying advanced liver fibrosis.

METHODS

Fifty-five HD patients (average HD duration 6 ± 2 years) with hyperferritinemia secondary to intravenous iron supplementation (weakly iron dose 252.7 ± 63 mg; median blood transfusions 3 [2-5]) were recruited. The liver fibrosis grade was determined with Fibroscan, aminotransferase-to-platelet ratio index (APRI), and Fib-4 index. Liver iron concentration (LIC) was estimated with magnetic resonance imaging (MRI). Iron parameters and liver function biochemical indicators were also assessed.

RESULTS

The median serum ferritin and transferrin saturation (TSAT) were 3531 μg/L and 77%, respectively. 34.5%, 20%, and 45.5% of the patients showed mild, moderate, or severe liver siderosis, respectively. All patients with severe liver siderosis showed advanced liver fibrosis. Patients with severe liver siderosis and advanced liver stiffness showed higher serum iron, TSAT, aspartate aminotransferase (AST), alanine aminotransferase (ALT), serum bilirubin, APRI, and Fib-4 index scores than those with mild liver siderosis. Serum iron and TSAT showed good utility in identifying advanced liver fibrosis determined with Fibroscan, APRI, and Fib-4 index. Liver stiffness exhibited good utility in identifying advanced liver fibrosis diagnosed with APRI and Fib-4 index.

CONCLUSIONS

High weekly intravenous iron dose associated with severe hyperferritinemia, high serum iron, and TSAT might lead to severe liver siderosis and concomitant liver fibrosis in HD patients. Serum iron, TSAT, Fibroscan, Fib-4, and APRI scores might offer noninvasive tools for identifying advanced liver fibrosis in those patients.

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.

Predictors of iron versus erythropoietin responsiveness in anemic hemodialysis patients

Anemia protocols for hemodialysis patients usually titrate erythropoietin (ESA) according to hemoglobin and iron according to a threshold of ferritin, with variable response seen. A universally optimum threshold for ferritin may be incorrect, and another view is that ESA and iron are alternative anemia treatments, which should be selected based on the likely response to each. Hemodialysis patients developing moderate anemia were randomised to treatment with either an increase in ESA or a course of intravenous iron. Over 2423 patient-months in 197 patients, there were 133 anemia episodes with randomized treatment. Treatment failure was seen in 20/66 patients treated with ESA and 20/67 patients treated with iron (30.3 vs. 29.9%, p = 1.0). Successful ESA treatment was associated with lower C-reactive protein (13.5 vs. 28.6 mg/L, p = 0.038) and lower previous ESA dose (6621 vs. 9273 μg/week, p = 0.097). Successful iron treatment was associated with lower reticulocyte hemoglobin (33.8 vs. 35.5 pg, p = 0.047), lower hepcidin (91.4 vs. 131.0 μg/ml, p = 0.021), and higher C-reactive protein (29.5 vs. 12.6 mg/L, p = 0.085). A four-variable iron preference score was developed to indicate the more favorable treatment, which in a retrospective analysis reduced treatment failure to 17%. Increased ESA and iron are equally effective, though treatment failure occurs in almost 30%. Baseline variables including hepcidin can predict treatment response, and a four-variable score shows promise in allowing directed treatment with improved response rates.

Pharmacokinetics and Safety of Ferric Pyrophosphate Citrate Intravenous: Equivalence to Administration via Dialysate

Ferric pyrophosphate citrate (FPC) is indicated to maintain hemoglobin in patients with stage 5 hemodialysis‐dependent chronic kidney disease on chronic hemodialysis by addition to the dialysate. An intravenous (IV) FPC presentation containing 6.75 mg of iron in 4.5 mL was developed. The objective was to establish the equivalence of iron delivery via dialysate and IV infusion using a pharmacokinetic approach. An open‐label, randomized, multiple‐period, single‐dose, crossover study was conducted in 27 patients with CKD‐5HD. Each patient received (1) a basal iron profile over 12 hours, (2) FPC 6.75 mg Fe IV predialyzer, (3) FPC 6.75 mg Fe IV postdialyzer, and (4) FPC 2 μM (110 μg Fe/L of hemodialysate). Serum and plasma iron was analyzed for total Fe and transferrin bound iron (TBI). Equivalence was determined by comparing maximum observed concentration and area under the concentration‐time curve from time 0 to the last observation of 110 μg Fe/L of hemodialysate (reference) and test treatments Fe predialyzer and postdialyzer iron profiles. The main outcome measure was the measurement of bioequivalence between the reference and test treatments. Bioequivalence parameters showed that infusion of FPC iron IV, predialyzer and postdialyzer delivered equivalent iron as via hemodialysate. The increment in serum total Fe from predialysis to postdialysis was the same as observed in the long‐term clinical studies of FPC. FPC IV was well tolerated. IV infusion of 6.75 mg iron as FPC during 3 hours of HD delivers an equivalent amount of iron as when Triferic is delivered via hemodialysate. The IV presentation of FPC extends the ability to provide FPC iron to all patients receiving hemodialysis or hemodiafiltration.

Anemia: A Connection Between Heart Failure and Kidney Failure

Erythropoiesis-stimulating agents (ESAs) have improved the quality of life and reduced the need for transfusions in patients with chronic kidney disease. However, randomized trials showed no benefit but possible safety issues following high doses of ESAs given to reach normal hemoglobin levels. Iron therapy is used together with ESA; when given proactively, it may reduce the risk of mortality and cardiovascular events in hemodialysis patients. Recent trials also showed benefits of intravenous iron therapy in patients with heart failure. New drugs for correcting anemia may retain the present efficacy of ESAs as antianemic drugs and reduce cardiovascular risks.

Types of erythropoiesis-stimulating agents and risk of end-stage kidney disease and death in patients with non-dialysis chronic kidney disease

BACKGROUND

Despite the widespread use of erythropoiesis-stimulating agents (ESAs) to treat anaemia, the risk of adverse outcomes associated with the use of different types of ESAs in non-dialysis chronic kidney disease (CKD) is poorly investigated.

METHODS

From a pooled cohort of four observational studies, we selected CKD patients receiving short-acting (epoetin α/β; n = 299) or long-acting ESAs (darbepoetin and methoxy polyethylene glycol-epoetin β; n = 403). The primary composite endpoint was end-stage kidney disease (ESKD; dialysis or transplantation) or all-cause death. Multivariable Cox models were used to estimate the relative risk of the primary endpoint between short- and long-acting ESA users.

RESULTS

During follow-up [median 3.6 years (interquartile range 2.1-6.3)], the primary endpoint was registered in 401 patients [166 (72%) in the short-acting ESA group and 235 (58%) in the long-acting ESA group]. In the highest tertile of short-acting ESA dose, the adjusted risk of primary endpoint was 2-fold higher {hazard ratio [HR] 2.07 [95% confidence interval (CI) 1.37-3.12]} than in the lowest tertile, whereas it did not change across tertiles of dose for long-acting ESA patients. Furthermore, the comparison of ESA type in each tertile of ESA dose disclosed a significant difference only in the highest tertile, where the risk of the primary endpoint was significantly higher in patients receiving short-acting ESAs [HR 1.56 (95% CI 1.09-2.24); P = 0.016]. Results were confirmed when ESA dose was analysed as continuous variable with a significant difference in the primary endpoint between short- and long-acting ESAs for doses >105 IU/kg/week.

CONCLUSIONS

Among non-dialysis CKD patients, the use of a short-acting ESA may be associated with an increased risk of ESKD or death versus long-acting ESAs when higher ESA doses are prescribed.

Intravenous iron therapy and the cardiovascular system: risks and benefits

Anaemia is a common complication of chronic kidney disease (CKD). In this setting, iron deficiency is frequent because of the combination of increased iron needs to sustain erythropoiesis with increased iron losses. Over the years, evidence has accumulated on the involvement of iron in influencing pulmonary vascular resistance, endothelial function, atherosclerosis progression and infection risk. For decades, iron therapy has been the mainstay of therapy for renal anaemia together with erythropoiesis-stimulating agents (ESAs). Despite its long-standing use, grey areas still surround the use of iron therapy in CKD. In particular, the right balance between either iron repletion with adequate therapy and the avoidance of iron overload and its possible negative effects is still a matter of debate. This is particularly true in patients having functional iron deficiency. The recent Proactive IV Iron Therapy in Haemodialysis Patients trial supports the use of intravenous (IV) iron therapy until a ferritin upper limit of 700 ng/mL is reached in haemodialysis patients on ESA therapy, with short dialysis vintage and minimal signs of inflammation. IV iron therapy has also been proven to be effective in the setting of heart failure (HF), where it improves exercise capacity and quality of life and possibly reduces the risk of HF hospitalizations and cardiovascular deaths. In this review we discuss the risks of functional iron deficiency and the possible benefits and risks of iron therapy for the cardiovascular system in the light of old and new evidence.

ESA, Iron Therapy and New Drugs: Are There New Perspectives in the Treatment of Anaemia?

Anemia is a well-known consequence of chronic kidney disease (CKD); it is mainly due to a relative insufficiency of erythropoietin synthesis by the failing kidneys. Over the years, the combination of erythropoiesis stimulating agents (ESA) and iron has become the standard of care of anemia. All ESAs effectively increase hemoglobin (Hb) levels in a substantial percentage of patients. However, in the last decade, their use has been surrounded by safety issues in increased cardiovascular risk, especially when used at high doses in inflamed and hyporesponsive patients. This has led to the definition of a more cautious Hb target. Iron deficiency is very frequent in CKD patients, with a higher frequency in non-dialysis patients. Traditionally, iron supplementation is mostly used as supportive therapy for anemia control. However, the concept is growing that intravenous iron therapy per se could be beneficial in the presence of heart failure. A new class of drugs, prolyl hydroxylase domain (PHD) inhibitors (PHD inhibitors) is becoming available for the treatment of anemia in CKD patients. Theoretically, these agents have a number of advantages, the main ones being that of stimulating the synthesis of endogenous erythropoietin and increasing iron availability. The impact of their future use in clinical practice is still to be defined. Another possible strategy could be targeting serum hepcidin and its related pathways. This possibility is fascinating from the scientific point of view, but at present its development phase is still far from clinical application.

Prevalence, associated factors and cardiocerebral vascular prognosis of anaemia among patients on chronic haemodialysis in South Guangdong, China

OBJECTIVE

To assess the prevalence, associated factors and cardiocerebral vascular prognosis of anaemia in patients undergoing haemodialysis.

METHODS

This multicentre, retrospective, observational cohort study included patients on maintenance haemodialysis in South Guangdong, China. Anaemia in haemodialysis was defined as haemoglobin (Hb) <90 g/l. A proportion of patients were enrolled in a follow-up of the cardiocerebral vascular prognosis.

RESULTS

A total of 1161 patients were enrolled and 938 were followed-up for cardiocerebral vascular events. Of 1161 patients, 250 (21.5%) had anaemia and 524 (45.1%) had an Hb level of 100-120 g/l. Adjusted multivariate logistic regression analysis demonstrated that frequency of dialysis ≤ twice weekly, hypoalbuminaemia and use of unfractionated heparin were independent factors associated with anaemia. Kaplan-Meier survival curve analysis for no myocardial infarction was 100%, 100%, 100% and 100% after 3, 6, 9 and 12 months, respectively, in patients with Hb < 90 g/l; compared with 97%, 95%, 93% and 93%, respectively, in patients with Hb ≥ 130 g/l. Adjusted Cox proportional hazards regression demonstrated that Hb ≥ 130 g/l was an independent risk factor for myocardial infarction.

CONCLUSION

Anaemia is highly prevalent among patients undergoing haemodialysis in South Guangdong and requires careful management.

Clinical and Economic Outcomes of Erythropoiesis-Stimulating Agent Hyporesponsiveness in the Post-Bundling Era

Rationale & Objective

Since the change in erythropoiesis-stimulating agent (ESA) labeling and bundling of dialysis services in the United States, few studies have addressed the clinical importance of ESA hyporesponsiveness and none have considered health care resource use in this population. We aimed to further explore ESA hyporesponsiveness and its consequences.

Study Design

Retrospective observational cohort study.

Setting & Participants

US Renal Data System Medicare participants receiving dialysis with a minimum 6 months of continuous ESA use from 2012 to 2014.

Predictors

Erythropoietin resistance index (≥2.0 U/kg/wk/g/L) and ESA dose were used to identify ESA hyporesponders and hyporesponsive subgroups: isolated, intermittent, and chronic.

Outcomes

Associations between ESA responsiveness and mortality, cardiovascular hospitalization rates, and health care resource use were evaluated and compared across subgroups.

Analytical Approach

Baseline characteristics were compared using Wilcoxon rank sum tests for continuous variables and χ² tests for categorical variables. Incidence rates of health care resource use were modeled using an unadjusted and adjusted generalized linear model.

Results

Of 834,115 dialysis patients in the CROWNWeb database, 38,891 ESA hyporesponders and 59,412 normoresponders met all inclusion criteria. Compared with normoresponders, hyporesponders were younger women, weighed less, and had longer durations of dialysis (all P < 0.001). Hyporesponders received 3.8-fold higher ESA doses (mean, 94,831 U/mo) and erythropoietin resistance index was almost 5 times higher than in normoresponders. Hyporesponders had lower hemoglobin levels and parathyroid hormone levels > 800 pg/mL, and iron deficiency was present in 26.5% versus 10.9% in normoresponders. One-year mortality was higher among hypo- compared with normoresponders (25.3% vs 22.6%). Hyporesponders also had significantly higher rates of hospitalization for cardiovascular events, emergency department visits, inpatient stays, home health agency visits, skilled nursing facility, and hospice days.

Limitations

Only US Medicare patients were included and different hyporesponder definitions may have influenced the results.

Conclusions

This study explored ESA hyporesponsiveness using new definitions and incorporated clinical and economic outcomes. It established that ESA-hyporesponsive dialysis patients had higher mortality, cardiovascular hospitalization rates, and health care costs as compared with ESA-normoresponsive patients.

Efficacy and safety of a low monthly dose of intravenous iron sucrose in peritoneal dialysis patients

PURPOSE

Scientific data regarding intravenous iron supplementation in peritoneal dialysis (PD) patients are scarce. In attempting to administer the minimum monthly IV iron dose that could improve erythropoiesis, we wanted to assess the safety and efficacy of monthly maintenance intravenous administration of 100 mg iron sucrose in PD patients.

METHODS

In a 9-month prospective study, all clinically stable PD patients received intravenously 200 mg of iron sucrose as a loading dose, followed by monthly doses of 100 mg for five consecutive months. Levels of hemoglobin (Hb), ferritin, transferrin saturation (TSAT), reticulocyte hemoglobin content (CHr) and C-reactive protein (CRP) were measured before each administration and 3 months after the last iron infusion. Also, doses of concurrent erythropoietin administration were recorded.

RESULTS

Eighteen patients were eligible for the study. Mean levels of Hb and ferritin increased significantly (from 10.0 to 10.9 mg/dL, p = 0.01 and from 143 to 260 ng/mL, p = 0.005), as well as the increase in TSAT levels approached borderline significance (from 26.2 to 33.1%, p = 0.07). During the 6 months of iron administration, the erythropoietin dose was reduced in five patients and discontinued in one. During the 3 months following the last iron infusion, three of them again raised the erythropoietin dose to previous levels. None of the patients experienced any side effects related to IV iron administration.

CONCLUSIONS

A monthly maintenance intravenous dose of 100 mg iron sucrose may be a practical, effective, and safe in the short term, treatment of anemia in PD patients resulting in improved hemoglobin levels, iron indices, and erythropoietin response.

International Anemia Prevalence and Management in Peritoneal Dialysis Patients

Background:The optimal treatment for managing anemia in peritoneal dialysis (PD) patients and best clinical practices are not completely understood. We sought to characterize international variations in anemia measures and management among PD patients.Methods:The Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS) enrolled adult PD patients from 6 countries from 2014 to 2017. Hemoglobin (Hb), ferritin levels, and transferrin saturation (TSAT), as well as erythropoiesis stimulating agents (ESAs) and iron use were compared cross-sectionally at study enrollment in Australia and New Zealand (A/NZ), Canada, Japan, the United Kingdom (UK), and the United States (US).Results:Among 3,603 PD patients from 193 facilities, mean Hb ranged from 11.0 - 11.3 g/dL across countries. The majority of patients (range 53% - 59%) had Hb 10 - 11.9 g/dL, with 4% - 12% patients ≥ 13 g/dL and 16% - 23% < 10 g/dL. Use of ESAs was higher in Japan (94% of patients) than elsewhere (66% - 79% of patients). In the US, 63% of patients had a ferritin level > 500 ng/mL, compared with 5% - 38% in other countries. In the US and Japan, 87% - 89% of PD patients had TSAT ≥ 20%, compared with 73% - 76% in other countries. Intravenous (IV) iron use within 4 months of enrollment was higher in the US (55% of patients) than elsewhere (6% - 17% patients).Conclusions:In this largest international observational study of anemia and anemia management in patients receiving PD, comparable Hb levels across countries were observed but with notable differences in ESA and iron use. Peritoneal dialysis patients in the US have higher ferritin levels and higher IV iron use than other countries.

Infectious complications and mortality associated with the use of IV iron therapy: a systematic review and meta-analysis

BACKGROUND

Parental iron is used to optimize hemoglobin and enhance erythropoiesis in end-stage renal disease along with erythropoietin-stimulating agents. Safety of iron has been debated extensively and there is no definite evidence whether parenteral iron increases the risk of infections and mortality. We performed this meta-analysis to evaluate the incidence of infectious complications, hospitalizations and mortality with use of parenteral iron.

METHODS

Medical electronic databases [PubMed, EMBASE, Scopus, Web of Science, and cochrane central register for controlled clinical trials (CENTRAL)] were queried for studies that investigated the association between intravenous iron administration and infection in hemodialysis patients. 24 studies (8 Randomized control trials (RCTs) and 16 observational studies) were considered for qualitative and quantitative analysis.

RESULTS

All-cause mortality Data from 6 RCTs show that high-dose IV iron conferred 17% less all-cause mortality compared to controls; however, this outcome was not statistically significant (OR = 0.83, CI [0.7, 1.01], p = 0.07). Nine observational studies were pooled under the random effects model due to significant heterogeneity (I² = 83%, p < 0.001). The overall HR showed increased risk of all-cause mortality in the high-dose group but was statistically non-significant (HR = 1.1, CI [1, 1.22], p = 0.06). Infections Four RCTs with no heterogeneity among their data (I² = 0%, p = 0.61). Under the fixed effect model, there was no difference in the infection rate between high-dose iron and control group (OR = 0.97, CI [0.82, 1.16], p = 0.77); eight observational studies with significant heterogeneity and utilizing random effects model. Summary HR showed increased yet non-significant risk of infection in the high-dose group (HR = 1.13, CI [0.99, 1.28], p = 0.07) Hospitalization 1 RCT and six observational studies provided data for the rate of all-cause hospitalization. There was marked heterogeneity among observational studies. RCT showed no significant difference between high-dose iron and controls in the rate of hospitalization (OR = 1.03, CI [0.87, 1.23], p = 0.71). Summary HR for observational data showed increased rate of hospitalization in the high-dose group; however, this effect was not statistically significant (HR = 1.11, CI [0.99, 1.24], p = 0.07). Cardiovascular events One RCT compared the rate of adverse cardiovascular events between high-dose and low-dose iron. No significant difference was observed between the two groups (22.3% vs 25.6%, p = 0.12). Six heterogeneous observational studies (I² = 65%, p < 0.001) reported on the rate of cardiovascular events. No significant difference was observed between high-dose iron and controls (HR = 1.18, CI [0.89, 1.57], p = 0.24).

CONCLUSION

High-dose parenteral iron does not seem to be associated with higher risk of infection, all-cause mortality, increased hospitalization or increased cardiovascular events on analysis of RCTs. Observational studies show increased risk for all-cause mortality, infections and hospitalizations that were not statistically significant and were associated with significant heterogeneity.

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.

Evaluation of iron stores in hemodialysis patients on maintenance ferric Carboxymaltose dosing

Background

Iron is administered intravenously (IV) to many dialysis patients at regular intervals and iron stores are evaluated through periodic measurements of ferritin and transferrin saturation (TSAT). In patients without kidney diseases, large single doses of IV iron lead to a transient rise in serum ferritin that does not reflect iron stores. It is not known whether and to what extent smaller IV iron doses used to maintain adequate stores in hemodialysis patients lead to transient spurious elevations of ferritin and TSAT.

Methods

Ferritin and TSAT were serially determined over four weeks after the administration of ferric carboxymaltose (FCM) in hemodialysis patients on a stable maintenance FCM dosing regimen of 100 mg or 200 mg every four weeks.

Results

Ferritin values increased by 113 ± 72.2 μg/l (P < 0.001) from baseline to the peak value and remained significantly elevated until two weeks after the administration of 100 mg FCM (n = 19). After the administration of 200 mg FCM (n = 12), ferritin values increased by 188.5 ± 67.56 μg/l (P < 0.001) and remained significantly elevated by the end of week three. TSAT values increased by 12.0 ± 9.7% (P < 0.001) and 23.1 ± 20.4% (P = 0.002) in patients receiving 100 or 200 mg FCM, respectively, and returned to baseline within four days.

Conclusions

IV administration of FCM at doses of 100 or 200 mg in hemodialysis patients leads to dose-dependent transient ferritin elevations of extended duration. Temporal coordination of blood sampling for iron status evaluation with the maintenance IV iron dosing schedule is advisable.

Trial registration

ISRCTN12825165 (retrospectively registered 01/02/2019).

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1263-8) contains supplementary material, which is available to authorized users.

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

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