Safety and Efficacy of Intravenous Ferric Carboxymaltose (750 mg) in the Treatment of Iron Deficiency Anemia: Two Randomized, Controlled Trials

Characterization of serum phosphate levels over time with intravenous ferric carboxymaltose versus placebo as treatment for heart failure with reduced ejection fraction and iron deficiency: An exploratory prospective substudy from HEART-FID

AIMS

Ferric carboxymaltose (FCM) is guideline-recommended for iron deficiency (ID) in heart failure with reduced ejection fraction (HFrEF). Despite a well-established safety profile, the magnitude and clinical significance of FCM-induced hypophosphataemia in HFrEF remains unclear. This pre-specified substudy of HEART-FID evaluated serum phosphate, 1,25-dihydroxyvitamin D, and plasma parathyroid hormone (PTH) subsequent to FCM.

METHODS AND RESULTS

HEART-FID was a randomized, double-blind, placebo-controlled trial of ambulatory patients with HFrEF and ID randomized to FCM versus placebo. This substudy assessed mean change from baseline across eight visits over 6 months for the following endpoints: serum phosphate, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and PTH, in addition to the clinical severity of potential hypophosphataemia. Overall, 133 patients (n = 62 FCM, n = 71 placebo) were prospectively enrolled. Mean age was 68 ± 11 years, 55 (41.4%) were women, and 29 (21.8%) had chronic kidney disease. Phosphate levels decreased in 34 (57.6%) patients in the FCM group compared with 7 (10.3%) in the placebo group. Mean change in phosphate levels reached a nadir at day 21 (-0.36 ± 0.27 mmol/L) subsequent to FCM infusion with 28 (51%) having moderate-to-severe hypophosphataemia. Reductions in 1,25-dihydroxyvitamin D were also observed, whilst PTH increased. These biochemical changes returned to baseline levels by day 91. Serum levels of 25-hydroxyvitamin D remained stable throughout the study. No serious adverse events associated with hypophosphataemia were reported.

CONCLUSIONS

Transient moderate-to-severe hypophosphataemia was frequent subsequent to FCM infusion, accompanied by 1,25-dihydroxyvitamin D decrease and PTH increase. Serum levels of 25-hydroxyvitamin D remained stable. No evidence of symptomatic hypophosphataemia was reported, collectively indicating FCM-related hypophosphataemia to be clinically benign and transient in HFrEF.

Safety and Efficacy of Ferric Carboxymaltose in Heart Failure With Preserved Ejection Fraction and Iron Deficiency

Heart Failure with Preserved Ejection Fraction (HFpEF) is a prevalent cardiovascular condition characterized by a complex pathophysiology and limited therapeutic options. Coinciding iron deficiency often compounds the clinical picture, contributing to symptom burden and adverse outcomes. The review underscores the urgency for effective treatments in light of its increasing incidence and considerable healthcare burden. It highlights the clinical significance of addressing iron deficiency in HFpEF patients. FCM emerges as a promising therapeutic modality, demonstrating the ability to rapidly restore iron stores and enhance patients' quality of life while reducing hospitalization rates and mortality. The review thoroughly elucidates the impact of iron deficiency on HFpEF symptoms and outcomes, elucidating how FCM effectively mitigates these challenges. Detailed discussions encompass FCM's mechanism of action, pharmacokinetics, and safety profile. Notably, FCM's adaptability to diverse patient profiles and clinical settings is emphasized, reinforcing its clinical utility. Clinical evidence, including study designs, patient cohorts, and key findings, affirms FCM's potential as a valuable therapeutic option. Real-world data analysis further underscores FCM's practicality and safety beyond controlled clinical trials. The review concludes by addressing future research directions and critical research gaps, accentuating the need for mechanistic insights, long-term outcome studies, and refined patient selection criteria. As FCM increasingly integrates into clinical practice, it offers promise in revolutionizing HFpEF management, addressing an unmet need in this intricate cardiovascular condition.

Efficacy and Safety of Intravenous Ferric Carboxymaltose Treatment of Iron Deficiency Anaemia in Patients with Corpus Atrophic Gastritis: A Retrospective Study

Corpus Atrophic Gastritis (CAG) is characterised by iron malabsorption leading to iron deficiency anaemia (IDA), which rarely responds to oral therapy. Ferric carboxymaltose (FCM), shown to be a safe and effective intravenous iron therapy in other diseases, has not been investigated yet in CAG. Thus, we aimed to assess the safety and efficacy of FCM in CAG-related IDA. A retrospective study on 91 patients identified CAG as the only cause of IDA treated with FCM. Twenty-three were excluded for incomplete follow-up. Sixty-eight were evaluated for safety and efficacy, while three were evaluated for safety only due to infusion interruption for side effects. Haemoglobin and iron storage were evaluated pre-infusion (T0), at 4 weeks (T4) and 12 weeks (T12) after infusion. An eventual IDA relapse was analysed. Two cases reported mild side effects. Haemoglobin significantly increased at T4, and T12, reaching +3.1 g/dL. Ferritin increased at T4, decreasing at T12, while transferrin saturation increased progressively until reaching a plateau. IDA relapsed in 55.4% of patients at a mean of 24.6 months. The only factor associated with relapse was female gender [OR (95% CI): 6.6 (1.5-28.6)]. FCM proved to be safe and effective in treating CAG-related IDA, ensuring quick and long-lasting recovery.

[Hypophosphatemia after injectable iron treatments in adults: Comparison between ferric carboxymaltose and iron sucrose]

Hypophosphatemia is a recognized side effect of treatment of iron deficiency anemias with injectable iron. We analyzed 35 clinical trials that used ferric carboxymaltose (FCM) or iron sucrose (IS). Hypophosphatemia prevalence ranged from 0 to 91.7%. FCM-induced a significant (P<0.001) greater hypophosphatemia prevalence and phosphatemia decrease than IS (52.0% [95% CI: 42.2-61.8%] vs. 7.7% [95% CI: -2.8 to 18.2%] and -1.12mmol/L [95% CI: -1.36 to -0.89mmol/L] vs. -0.13mmol/L [95% CI: -0.59 to 0.32mmol/L]). FCM-induced hypophosphatemia was dose-dependent. The nadir of hypophosphatemia was reached in almost all studies after 7 and 14days. Hypophosphatemia persisted at the end of the study in 53.8% of the reported studies that used FCM and lasted up to 6months. FCM-induced an increase in intact circulating fibroblast growth factor 23 and in renal phosphorus excretion while serum 1-25 dihydroxyvitamin D was decreased. Risk factors for hypophosphatemia after FCM therapy were low basal circulating phosphate or ferritin, low body weight, high glomerular filtration rate, serum parathyroid hormone or hemoglobin and age, whereas renal insufficiency was associated with a lower risk. In conclusion, hypophosphatemia is common after treatment with injectable iron, FCM being associated with a higher risk than IS and with disorders of phosphocalcium metabolism. Monitoring of blood phosphate and 1-25 dihydroxyvitamin D could be considered during FCM therapy.

Precision Medicine in Erythropoietin Deficiency and Treatment Resistance: A Novel Approach to Management of Anaemia in Chronic Kidney Disease

The study of anaemia is a well-developed discipline where the concepts of precision medicine have, in part, been researched extensively. This review discusses the treatment of erythropoietin (EPO) deficiency anaemia and resistance in cases of chronic kidney disease (CKD). Traditionally, erythropoietin-stimulating agents (ESAs) and iron supplementation have been used to manage anaemia in cases of CKD. However, these treatments pose potential risks, including cardiovascular and thromboembolic events. Newer treatments have emerged to address these risks, such as slow-release and low-dosage intravenous iron, oral iron supplementation, and erythropoietin-iron combination therapy. Another novel approach is the use of hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs). This review highlights the need for precision medicine targeting the genetic components of EPO deficiency anaemia in CKD and discusses individual variability in genes such as the erythropoietin gene (EPO), the interleukin-β gene (IL-β), and the hypoxia-inducible factor gene (HIF). Pharmacogenetic testing aims to provide targeted therapies and interventions that are tailored to the specific characteristics of an individual, thus optimising treatment outcomes and minimising resistance and adverse effects. This article concludes by suggesting that receptor modification has the potential to revolutionise the treatment outcomes of patients with erythropoietin deficiency anaemia through the integration of the mentioned approach.

High-Dose Intravenous Iron with Either Ferric Carboxymaltose or Ferric Derisomaltose: A Benefit-Risk Assessment

The intravenous iron formulations ferric carboxymaltose (FCM) and ferric derisomaltose (FDI) offer the possibility of administering a large amount of iron in one infusion. This results in faster correction of anemia and the formulations being better tolerated than oral iron formulations. This triad of logistic advantages, improved patient convenience, and fast correction of anemia explains the fact that intravenous iron formulations nowadays are frequently prescribed worldwide in the treatment of iron deficiency anemia. However, these formulations may result in hypophosphatemia by inducing a strong increase in active fibroblast growth factor-23 (FGF-23), a hormone that stimulates renal phosphate excretion. This effect is much more pronounced with FCM than with FDI, and therefore the risk of developing hypophosphatemia is remarkably higher with FCM than with FDI. Repeated use of FCM may result in severe osteomalacia, which is characterized by bone pain, Looser zones (pseudofractures), and low-trauma fractures. Intravenous iron preparations are also associated with other adverse effects, of which hypersensitivity reactions are the most important and are usually the result of a non-allergic complement activation on nanoparticles of free labile iron-Complement Activation-Related Pseudo-Allergy (CARPA). The risk on these hypersensitivity reactions can be reduced by choosing a slow infusion rate. Severe hypersensitivity reactions were reported in < 1% of prospective trials and the incidence seems comparable between the two formulations. A practical guideline has been developed based on baseline serum phosphate concentrations and predisposing risk factors, derived from published cases and risk factor analyses from trials, in order to establish the safe use of these formulations.

Hypophosphatemic osteomalacia, a side effect of iron carboxymaltose administration

Carboxymaltose iron (Ferinject®) is a formulation for intravenous (iv) administration, used for the treatment of iron deficiency anemia and/or iron deficiency when oral administration of iron is not effective or due to intolerance. Its safety profile is excellent with few, but not nonexistent, side effects. Hypophosphatemia has been described as one of them. It is usually mild, transient and asymptomatic. However, in some cases it may be accompanied by nausea, asthenia, in addition to muscular and neurological symptoms and hematological alterations. It is, therefore, a potentially serious adverse effect whose prevalence is unknown and which requires high clinical suspicion to be detected.

Risk of Infection Associated With Administration of Intravenous Iron: A Systematic Review and Meta-analysis

IMPORTANCE

Intravenous iron is recommended by many clinical guidelines based largely on its effectiveness in reducing anemia. However, the association with important safety outcomes, such as infection, remains uncertain.

OBJECTIVE

To examine the risk of infection associated with intravenous iron compared with oral iron or no iron.

DATA SOURCES

Medline, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched for randomized clinical trials (RCTs) from 1966 to January 31, 2021. Ongoing trials were sought from ClinicalTrials.gov, CENTRAL, and the World Health Organization International Clinical Trials Search Registry Platform.

STUDY SELECTION

Pairs of reviewers identified RCTs that compared intravenous iron with oral iron or no iron across all patient populations, excluding healthy volunteers. Nonrandomized studies published since January 1, 2007, were also included. A total of 312 full-text articles were assessed for eligibility.

DATA EXTRACTION AND SYNTHESIS

Data extraction and risk of bias assessments were performed according to the Preferred Reporting Items of Systematic Reviews and Meta-analyses (PRISMA) and Cochrane recommendations, and the quality of evidence was assessed using the GRADE (Grades of Recommendation, Assessment, Development, and Evaluation) approach. Two reviewers extracted data independently. A random-effects model was used to synthesize data from RCTs. A narrative synthesis was performed to characterize the reporting of infection.

MAIN OUTCOMES AND MEASURES

The primary outcome was risk of infection. Secondary outcomes included mortality, hospital length of stay, and changes in hemoglobin and red blood cell transfusion requirements. Measures of association were reported as risk ratios (RRs) or mean differences.

RESULTS

A total of 154 RCTs (32 920 participants) were included in the main analysis. Intravenous iron was associated with an increased risk of infection when compared with oral iron or no iron (RR, 1.17; 95% CI, 1.04-1.31; I2 = 37%; moderate certainty of evidence). Intravenous iron also was associated with an increase in hemoglobin (mean difference, 0.57 g/dL; 95% CI, 0.50-0.64 g/dL; I2 = 94%) and a reduction in the risk of requiring a red blood cell transfusion (RR, 0.93; 95% CI, 0.76-0.89; I2 = 15%) when compared with oral iron or no iron. There was no evidence of an effect on mortality or hospital length of stay.

CONCLUSIONS AND RELEVANCE

In this large systematic review and meta-analysis, intravenous iron was associated with an increased risk of infection. Well-designed studies, using standardized definitions of infection, are required to understand the balance between this risk and the potential benefits.

Intravenous Iron-Induced Hypophosphatemia: An Emerging Syndrome

Some, but not all, intravenous iron formulations have been recognized to induce renal phosphate wasting syndrome. Most commonly this has been reported following treatment of iron deficiency anemia (IDA) with ferric carboxymaltose (FCM). A search of PubMed identified relevant randomized controlled trials (RCTs), and case studies evaluating hypophosphatemia (HPP) resulting from intravenous iron treatment. While more recent larger comparative RCTs have confirmed that the majority of patients receiving FCM, especially those with normal renal function, may experience severe HPP, complete documentation is hampered by inconsistent reporting of serum phosphate in such trials. Similarly, while case series and RCTs have documented the persistence of HPP for several weeks or even months, the lack of studies lasting beyond 5–6 weeks has constrained full understanding of the duration of effect. Clinical trials have established that the mechanism involves the bone/metabolic axis with the elevation of intact fibroblast growth factor 23 playing the central role. Reports continue to accumulate of the clinical consequences of severe HPP which are, most commonly, bone abnormalities following repetitive dosing. Case reports and studies, however, have also shown that symptomatic hypophosphatemia can occur after a single FCM dose. The frequency of such events remains unknown, in part due to lack of awareness of hypophosphatemia coupled with the fact that the most common acute symptoms of HPP (fatigue and weakness) are the same for IDA and for many of the chronic diseases that cause IDA. Changes to US and European prescribing information for FCM should raise awareness of the potential for HPP and need to monitor patients at risk for it.

Parenteral iron therapy and phosphorus homeostasis: A review

Phosphorus has an essential role in cellular and extracellular metabolism; maintenance of normal phosphorus homeostasis is critical. Phosphorus homeostasis can be affected by diet and certain medications; some intravenous iron formulations can induce renal phosphate excretion and hypophosphatemia, likely through increasing serum concentrations of intact fibroblast growth factor 23. Case studies provide insights into two types of hypophosphatemia: acute symptomatic and chronic hypophosphatemia, while considering the role of pre‐existing conditions and comorbidities, medications, and intravenous iron. This review examines phosphorus homeostasis and hypophosphatemia, with emphasis on effects of iron deficiency and iron replacement using intravenous iron formulations.

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.

Iron supplementation and iron-fortified foods: a review

About one-third of the world population is suffering from iron deficiency. Delivery of iron through diet is a practical, economical, and sustainable approach. Clinical studies have shown that the consumption of iron-fortified foods is one of the most effective methods for the prevention of iron deficiency. However, supplementing iron through diet can cause undesirable side-effects. Thus, it is essential to develop new iron-rich ingredients, iron-fortified products with high bioavailability, better stability, and lower cost. It is also essential to develop newer processing technologies for more effective fortification. This review compared the iron supplementation strategies used to treat the highly iron-deficient population and the general public. We also reviewed the efficacy of functional (iron-rich) ingredients that can be incorporated into food materials to produce iron-fortified foods. The most commonly available foods, such as cereals, bakery products, dairy products, beverages, and condiments are still the best vehicles for iron fortification and delivery.Scope of reviewThe manuscript aims at providing a comprehensive review of the latest publications that cover three aspects: administration routes for iron supplementation, iron-rich ingredients used for iron supplementation, and iron-fortified foods.

Hypophosphataemia after treatment of iron deficiency with intravenous ferric carboxymaltose or iron isomaltoside-a systematic review and meta-analysis

Aims

Hypophosphataemia is an increasingly recognized side‐effect of ferric carboxymaltose (FCM) and possibly iron isomaltoside/ferric derisomaltose (IIM), which are used to treat iron deficiency. The aim of this study was to determine frequency, severity, duration and risk factors of incident hypophosphataemia after treatment with FCM and IIM.

Methods

A systematic literature search for articles indexed in EMBASE, PubMed and Web of Science in years 2005–2020 was carried out using the search terms ‘ferric carboxymaltose’ OR ‘iron isomaltoside’. Prospective clinical trials reporting outcomes on hypophosphataemia rate, mean nadir serum phosphate and/or change in mean serum phosphate from baseline were selected. Hypophosphataemia rate and severity were compared for studies on IIM vs. FCM after stratification for chronic kidney disease. Meta‐regression analysis was used to investigate risk factors for hypophosphataemia.

Results

Across the 42 clinical trials included in the meta‐analysis, FCM induced a significantly higher incidence of hypophosphataemia than IIM (47%, 95% CI 36–58% vs. 4%, 95% CI 2–5%), and significantly greater mean decreases in serum phosphate (0.40 vs. 0.06 mmol/L). Hypophosphataemia persisted at the end of the study periods (maximum 3 months) in up to 45% of patients treated with FCM. Meta‐regression analysis identified low baseline serum ferritin and transferrin saturation, and normal kidney function as significant predictors of hypophosphataemia.

Conclusion

FCM is associated with a high risk of hypophosphataemia, which does not resolve for at least 3 months in a large proportion of affected patients. More severe iron deficiency and normal kidney function are risk factors for hypophosphataemia.

Comparative Risk of Hypophosphatemia Following the Administration of Intravenous Iron Formulations: A Network Meta-Analysis

Intravenous iron therapy is increasingly used in patients with iron deficiency anemia, although concerns of hypophosphatemia have been recently raised. The aim of this study was to evaluate different intravenous iron formulations for the risk of hypophosphatemia. Medline, Scopus, Cochrane Central Register of Controlled Trials, Web of Science, Clinicaltrials.gov, and Google Scholar databases were systematically searched to 20 March 2020. All randomized controlled trials reporting the incidence of hypophosphatemia among adult patients treated with any intravenous iron preparation were included. Pool estimates were obtained by applying an arm-based Bayesian network meta-analysis model. Eight randomized controlled trials were included, comprising 5989 patients. Ferric carboxymaltose was associated with significantly higher incidence of hypophosphatemia compared to iron isomaltoside (risk ratio [RR]: 7.90, 95% confidence interval [CI]: 2.10-28.0), iron sucrose (RR: 9.40, 95% CI: 2.30-33.0), iron dextran (RR: 6.60, 95% CI: 1.91-220.0), and ferumoxytol (RR: 24.0, 95% CI: 2.50-220.0). Therefore, ferric carboxymaltose ranked as the worst treatment presenting the highest surface under the cumulative ranking curve (99.1%). No significant differences were estimated for the comparisons among iron isomaltoside, iron sucrose, iron dextran, and ferumoxytol. In conclusion, it is suggested that the occurrence of hypophosphatemia is common after the administration of intravenous ferric carboxymaltose. Further research is needed in large-scale randomized controlled trials to determine the risk of symptomatic and persistent hypophosphatemia as well as to elucidate the exact pathophysiology of the observed association.

Hypophosphatemia Associated with Intravenous Iron Therapies for Iron Deficiency Anemia: A Systematic Literature Review

Background

Iron deficiency anemia (IDA) is a prevalent yet underdiagnosed condition with a significant impact on quality of life. Oral iron supplementation is often poorly tolerated or yields inadequate response, requiring the use of intravenous iron (IVI) in some patients. Administration of certain IVI preparations has been associated with decreases in serum phosphate levels and clinically significant hypophosphatemia, which has been reported to lead to adverse events including serious fatigue and osteomalacia.

Objective

The purpose of this study was to systematically assess the prevalence, clinical consequences, and reporting of treatment-emergent hypophosphatemia within literature investigating IVI therapies marketed in the United States (US).

Methods

A systematic literature review (SLR) was conducted using the PubMed database to identify publications reporting serum phosphate levels or rates of hypophosphatemia within adult IDA patient populations receiving current US-marketed IVIs.

Results

The SLR yielded 511 unique publications, with 40 records meeting the final inclusion criteria. Most studies did not report phosphate monitoring methodology or an explicit definition of hypophosphatemia. Hypophosphatemia rates ranged from 0.0% to 92.1% for ferric carboxymaltose (FCM), 0.0% to 40.0% for iron sucrose, 0.4% for ferumoxytol, and 0.0% for low-molecular-weight (LMW) iron dextran. Randomized controlled studies described hypophosphatemia as “asymptomatic” or did not report on other associated sequelae. Eleven case reports detailed treatment-emergent hypophosphatemia in patients treated with FCM. Patients with acute hypophosphatemia primarily developed severe fatigue; those with repeated FCM dosing developed chronic hypophosphatemia associated with osteomalacia and bone deformities.

Conclusion

Studies analyzed in this SLR reported a range of hypophosphatemia rates, with the highest consistently seen in patients treated with FCM. Across the clinical literature, there appeared to be minimal standardization of phosphate monitoring and definitions of hypophosphatemia. Although multiple cases have documented serious clinical consequences of hypophosphatemia associated with certain IVIs, current trials neither consistently nor adequately assess the frequency and severity of treatment-emergent hypophosphatemia and may underestimate its prevalence.

High Risk of Hypophosphatemia in Patients with Previous Bariatric Surgery Receiving Ferric Carboxymaltose: A Prospective Cohort Study

BACKGROUND

Iron deficiency is a common finding in patients with previous bariatric surgery, and parenteral supplementation is frequently required. Ferric carboxymaltose (FCM) is among the preferred compounds used but may be associated with new-onset hypophosphatemia. This study was undertaken to study the prevalence of hypophosphatemia following FCM in patients with previous bariatric surgery, a population that may be at particular risk due to highly prevalent secondary hyperparathyroidism.

METHODS

Patients with previous bariatric surgery and iron depletion scheduled for FCM infusion were prospectively studied before and one week after FCM application. The primary endpoint was new-onset hypophosphatemia. Patients were followed until plasma phosphate had normalized without replacement.

RESULTS

Fifty-two patients (40 females) following Roux-en-Y gastric bypass (n = 50) or sleeve gastrectomy (n = 2), with a median age of 46 years (range 22-68) and a BMI of 32.2 kg/m² (27.5-37.3), were analyzed. Fifteen patients (29%) developed new-onset hypophosphatemia, with 11 (21%) requiring oral phosphate supplementation for a median duration of 14 days (14-25). The plasma phosphate decreased by 0.3 mmol/l (-0.5--0.2; p < 0.001) secondary to a 56% increase in the fractional urinary phosphate excretion (p < 0.001). This was associated with a significant increase in serum intact FGF23 (+30%; p < 0.001) and a decrease in serum 1,25(OH)2 vitamin D3 concentrations (-37.6%; p < 0.001).

CONCLUSION

Patients with previous bariatric surgery receiving FCM are at considerable risk of developing significant hypophosphatemia secondary to increased renal phosphate wasting through a mechanism involving FGF23. Monitoring plasma phosphate should be considered following FCM in patients with previous bariatric surgery.

CLINICAL TRIAL REGISTRATION

ISRCTN registry, ISRCTN12291677, https://www.isrctn.com.

Symptomatic hypophosphataemia after intravenous iron therapy: an underrated adverse reaction

Iron (ferric carboxymaltose) infusion therapy is used to treat severe iron deficiency which is not responding to the first-line oral iron therapy. However, it can also cause severe renal wasting of phosphate resulting in severe hypophosphataemia in some patients. Despite the growing number of case reports, this side effect is not well known to healthcare professionals. The product labelling information sheet does mention that hypophosphataemia can be a side effect, but also says that this side effect is usually transient and asymptomatic. We report a challenging case of a patient who developed severe, symptomatic and prolonged hypophosphataemia after an intravenous iron infusion for severe iron deficiency.

Ferric Carboxymaltose: A Review in Iron Deficiency

Intravenous ferric carboxymaltose (Ferinject^®; Injectafer^®) is a colloidal solution of nanoparticles which consist of a polynuclear iron (III)-(oxyhydr)oxide core stabilized by carboxymaltose and may be given as a single high-dose, 15-min infusion. This article reviews the clinical use of ferric carboxymaltose in various patient populations with iron deficiency (ID) [± anaemia] and briefly summarizes its pharmacological properties. Based on extensive experience in the clinical trial and real-world settings, ferric carboxymaltose is an effective and generally well tolerated treatment for rapidly replenishing iron stores and correcting anaemia in patients with ID (± anaemia) of various aetiologies, including patients with chronic heart failure (CHF), chronic kidney disease, inflammatory bowel disease or perioperative anaemia, and women with ID during pregnancy, postpartum or associated with heavy uterine bleeding. As it may be given as a single high-dose infusion, ferric carboxymaltose has the potential to provide cost savings from a healthpayer perspective. Thus, ferric carboxymaltose remains an important option for the treatment of ID in adults and, where approved, children aged ≥ 14 years, when oral iron preparations are ineffective or cannot be used.

Comparative safety of intravenous ferumoxytol versus ferric carboxymaltose in iron deficiency anemia: A randomized trial

Few trials have examined rates of hypersensitivity reactions (HSRs) with intravenous iron formulations used to treat iron deficiency anemia (IDA). This randomized, multicenter, double‐blind clinical trial compared the safety, and efficacy of ferumoxytol versus ferric carboxymaltose (FCM), focusing on rates of HSRs and hypotension as the primary end point. Patients with IDA of any etiology in whom oral iron was unsatisfactory or intolerable received ferumoxytol (n = 997) or FCM (n = 1000) intravenously over ≥15 minutes on days 1 and 8 or 9 for total respective doses of 1.02 g and 1.50 g. Composite incidences of moderate‐to‐severe HSRs, including anaphylaxis, or moderate‐to‐severe hypotension from baseline to week 5 (primary safety end point) were 0.6% and 0.7% in the ferumoxytol and FCM groups, respectively, with ferumoxytol noninferior to FCM. No anaphylaxis was reported in either group. The secondary safety end point of incidences of moderate‐to‐severe HSRs, including anaphylaxis, serious cardiovascular events, and death from baseline to week 5 were 1.3% and 2.0% in the ferumoxytol and FCM groups, respectively (noninferiority test P < .0001). Least‐squares mean changes in hemoglobin at week 5 were 1.4 g/dL and 1.6 g/dL in the ferumoxytol and FCM groups, respectively (noninferiority test P < .0001). Incidence of hypophosphatemia was 0.4% for ferumoxytol and 38.7% for FCM.

Improved Hemoglobin Response with Ferric Carboxymaltose in Patients with Gastrointestinal-Related Iron-Deficiency Anemia Versus Oral Iron

AIMS

To compare the efficacy and safety of intravenous (IV) ferric carboxymaltose (FCM) versus oral iron and other IV iron therapies in patients with iron-deficiency anemia (IDA) resulting from gastrointestinal (GI) disorders.

METHODS

A pooled analysis of four prospective, randomized, active-controlled trials in patients with IDA was performed. Efficacy measures included change from baseline in hemoglobin (Hb), ferritin, and transferrin saturation (TSAT) and correlations of baseline Hb, ferritin, and TSAT to change in Hb. The incidence and type of adverse events were evaluated.

RESULTS

A total of 191 patients were evaluated. The mean change in Hb from baseline to the maximum value was 0.8 g/dL with oral iron (P = 0.001 vs. FCM), 2.2 g/dL with FCM, 2.0 g/dL with any IV iron (P = 0.391 vs. FCM), and 1.9 g/dL with iron sucrose (P = 0.329 vs. FCM). Patients treated with FCM and iron sucrose had larger increases in Hb. This effect may have been attributed to a lower baseline Hb level. Drug-related adverse events occurred in 11.9, 12, 26.2, and 25% and serious adverse events (SAEs) occurred in 6.9, 4, 9.8, and 12.5% of patients in the FCM, oral iron, other IV iron therapies, and iron sucrose groups, respectively. No SAEs were considered treatment related in the FCM group, compared with two treatment-related SAEs in two patients (6.3%) in the iron sucrose group.

CONCLUSIONS

FCM is an effective therapy in patients with IDA who have GI disorders and has a safety profile comparable to that of other IV iron agents.

Iron Supplementation, Response in Iron-Deficiency Anemia: Analysis of Five Trials

BACKGROUND

Oral iron-replacement therapy is the mainstay of treatment for iron-deficiency anemia, but it is often poorly tolerated or ineffective. Hemoglobin response at day 14 of oral iron may be useful in assessing whether and when to transition patients from oral to intravenous (IV) iron.

METHODS

Pooled data from 5 randomized trials were analyzed to compare oral and IV iron-replacement therapy for iron-deficiency anemia. Treatment criteria and assignment to oral versus IV iron were defined per protocol; this analysis included only subjects receiving oral iron. Responders were subjects with ≥1.0-g/dL increases in hemoglobin at day 14, and nonresponders were those with smaller increases. Demographic and clinical characteristics were evaluated for association with hemoglobin response at multiple timepoints.

RESULTS

Most subjects (72.8%) were classified as responders. The proportion of subjects with hemoglobin increases ≥1.0, ≥2.0, and ≥3.0 g/dL was greatest among those with postpartum anemia, intermediate among those with heavy uterine bleeding or gastrointestinal-related causes of anemia, and lowest among those with other causes; this proportion was also significantly greater among responders than nonresponders. A ≥1.0-g/dL increase in hemoglobin on day 14 most accurately predicted satisfactory overall hemoglobin response to oral iron on day 42/56 (sensitivity 90.1%; specificity 79.3%; positive and negative predictive values of 92.9% and 72.7%, respectively). Iron-replacement therapy improved quality of life and reduced fatigue.

CONCLUSION

Hemoglobin responses <1.0 g/dL at day 14 of oral iron identify subjects with iron-deficiency anemia who should be transitioned to IV iron supplementation.

Efficacy and Tolerability of Intravenous Ferric Carboxymaltose in Patients with Iron Deficiency at a Hospital Outpatient Clinic: A Retrospective Cohort Study of Real-World Clinical Practice

Ferric carboxymaltose (FCM) is an intravenous iron formulation to correct iron deficiency. Although its use has been extensively studied in clinical trials, real-world evidence regarding FCM treatment is scarce. Our aim was to evaluate the efficacy and tolerability of FCM treatment in patients with iron deficiency, with or without anemia, at a hospital outpatient clinic. Data was collected retrospectively from medical records. During this 2-year study, 459 patients were included. Mean age was 58.6 ± 17.5 years and most patients received cumulative FCM doses of 501–1000 mg (63.2%). Six weeks after administration of FCM, efficacy endpoints hemoglobin increase ≥2 g/dL, hemoglobin increase ≥3 g/dL, and transferrin saturation > 20% were attained by 41%, 20%, and 63% of patients, respectively. Patients who received higher FCM doses showed significant reduced odds of not achieving hemoglobin increase ≥2 g/dL (501–1000 mg, adjusted odds ratio [OR]: 0.34, 95% confidence interval [CI] 0.18–0.62; 1001–3000 mg, OR: 0.19, 95% CI 0.07–0.49), compared to 500 mg doses. Treatment-emergent adverse events were documented in <4% of patients. In conclusion, FCM treatment was effective and well-tolerated by outpatients with iron deficiency at a hospital clinic, and its dosage should be adjusted to improve iron deficiency management in clinical practice.

Ferric Carboxymaltose as Treatment in Women with Iron-Deficiency Anemia

Objective. To evaluate safety and efficacy of intravenous ferric carboxymaltose (FCM) versus standard medical care (SMC) for iron-deficiency anemia (IDA) in postpartum women and women with heavy menstrual bleeding. Study Design. This open-label, multicenter study randomized women with IDA (hemoglobin ≤ 11.0 g/dL) to single doses of FCM (15 mg/kg [maximum 1000 mg]) or SMC (this treatment was determined by the investigator and there may have been no treatment). Safety data (primary outcome) were collected for 30 days. Results. Of 2045 subjects enrolled (FCM: n = 1023; SMC: n = 1022), 996 received FCM and 1022 received SMC. At least 1 serious adverse event (AE) was reported by 0.6% and 2.2% of subjects in the FCM and SMC groups, respectively; none were considered treatment related. The difference in serious AEs was primarily due to higher rates of uterine leiomyoma, uterine hemorrhage, and menorrhagia in SMC subjects with heavy menstrual bleeding. Common AEs were generally predictable, with higher rates of infusion site reactions in FCM subjects and gastrointestinal AEs in SMC subjects. Mean hemoglobin increases were greater in the FCM group than the SMC group. Conclusion. FCM was well tolerated and effectively increased mean hemoglobin levels in postpartum women or women with heavy menstrual bleeding and IDA. This trial is registered with ClinicalTrials.gov, NCT00548860.

Drug-specific hypophosphatemia and hypersensitivity reactions following different intravenous iron infusions

AIMS

Intravenous (IV) iron infusions have been associated with hypophosphataemia (HP) and hypersensitivity reactions (HSRs). No studies have compared the side effects of ferric carboxymaltose (FCM) with those of isomaltoside 1000 (ISM). This study aimed to describe the occurrence of HP and HSRs following the administration of either FCM or ISM.

METHODS

Data on 231 outpatients treated with IV iron infusions, between November 2011 and April 2014, were collected. During that period, the department made a switch from FCM to ISM and then back to FCM. Of the 231 patients, 39 received both FCM and ISM during the period. The prevalences of HP and HSRs were compared between the two drugs.

RESULTS

We found more HP events when FCM was given (64 vs. 9; P < 0.01). In contrast, more patients had mild HSRs when ISM was given (2.5% vs. 10.7%; P < 0.01). A comparison of the two drugs in the subpopulation who received both drug types (n = 39) revealed a difference in phosphate decrease (P < 0.01), with the most marked decrease occurring with FCM. Nine patients who had HSRs were exposed to both drugs. No potential HSR crossover between the two drugs was found.

CONCLUSION

We found a higher risk of HP with FCM administration when compared to ISM administration. Conversely, we found a higher risk of mild HSRs with ISM administration when compared to FCM administration. The impacts of the two types of side effects should be considered when choosing an IV iron drug.

Intravenous Ferric Carboxymaltose in Children with Iron Deficiency Anemia Who Respond Poorly to Oral Iron

OBJECTIVE

To assess the benefits and risks of intravenous (IV) ferric carboxymaltose (FCM) in children with iron deficiency anemia (IDA).

STUDY DESIGN

In a retrospective cohort study of patients seen at our center, we identified all FCM infusions in children with IDA over a 12-month period through a query of pharmacy records. Clinical data, including hematologic response and adverse effects, were extracted from the electronic medical record.

RESULTS

A total of 116 IV FCM infusions were administered to 72 patients with IDA refractory to oral iron treatment (median age, 13.7 years; range, 9 months to 18 years). Median preinfusion and postinfusion hemoglobin values were 9.1 g/dL and 12.3 g/dL, respectively (at 4-12 weeks after the initial infusion; n = 53). Sixty-five patients (84%) experienced no adverse effects. Minor transient complications were encountered during or immediately after 7 infusions.

CONCLUSION

FCM administered as a short IV infusion without a test dose proved to be safe and highly effective in a small yet diverse population of infants, children, and adolescents with IDA refractory to oral iron therapy.

Ferumoxytol versus iron sucrose treatment: a post-hoc analysis of randomized controlled trials in patients with varying renal function and iron deficiency anemia

Background

Iron deficiency anemia is highly prevalent in patients with chronic kidney disease and is often treated with intravenous iron. There are few trials directly comparing the safety and efficacy of different intravenous iron products.

Methods

This post-hoc analysis pooled data from 767 patients enrolled in two randomized, controlled, open-label trials of similar design comparing the treatment of iron deficiency anemia with ferumoxytol and iron sucrose across patients with all stages of renal function. One trial was conducted in adults with CKD either on or not on dialysis and the second in adults with IDA of any underlying cause and a history of unsatisfactory oral iron therapy or in whom oral iron could not be used who had normal to no worse than moderately impaired renal function. Patients were categorized by chronic kidney disease stage (i.e., estimated glomerular filtration rate), and the primary efficacy endpoint was the mean change in hemoglobin from Baseline to Week 5.

Results

The overall incidence of adverse events was numerically lower in ferumoxytol-treated patients compared to those treated with iron sucrose (42.4 vs. 50.2 %, respectively); the incidence of treatment-related adverse events was generally similar between the two treatment groups (13.6 vs. 16.0 %, respectively). Adverse events of Special Interest (i.e., hypotension, hypersensitivity) occurred at lower rates in those treated with ferumoxytol compared to those treated with iron sucrose (2.5 vs. 5.3 %, respectively). Overall, mean hemoglobin increased in both treatment groups, regardless of degree of renal insufficiency, although greater increases were seen among those with less severe kidney damage. Mean increases in hemoglobin from Baseline to Week 5 were significantly greater with ferumoxytol than with iron sucrose treatment in the subgroup with an estimated glomerular filtration rate ≥90 mL/min (Least Squares mean difference = 0.53 g/dL; p < 0.001). There were no other consistent, significant differences in hemoglobin levels between treatment groups for the other chronic kidney disease categories except for isolated instances favoring ferumoxytol.

Conclusions

The efficacy and safety of ferumoxytol is at least comparable to iron sucrose in patients with varying degrees of renal function.

Trial registration

(CKD-201; ClinicalTrials.gov identifier: NCT01052779; registered 15 January, 2010), (IDA-302; ClinicalTrials.gov identifier: NCT01114204; registered 29 April, 2010).

Electronic supplementary material

The online version of this article (doi:10.1186/s12878-016-0060-x) contains supplementary material, which is available to authorized users.

Influence of diet and supplements on iron status after gastric bypass surgery

BACKGROUND

Iron deficiency is common after Roux-en-Y gastric bypass (RYGB) surgery, but there is no consensus on the optimal diet quality and quantity for restoring and preserving iron status.

OBJECTIVES

The authors explored the impact of dietary and supplemental sources of iron and absorptive factors on iron status.

SETTING

Academic, United States.

METHODS

In a cross-sectional cohort of individuals who underwent RYGB, nutrient intakes from food and supplements were measured using 3-day food records. Blood biomarkers of iron status, including concentrations of ferritin, total iron binding capacity, serum transferrin receptor (sTfR), and the sTfR:ferritin ratio, were assessed by a reference laboratory; iron deficiency was defined as having at least 2 abnormal measures. Associations between iron status biomarkers and dietary predictors were determined using regression analysis.

RESULTS

Of the 36 participants, 97% were female, the mean age was 45 years (95% confidence interval, 41-48 years), and body mass index was 32 (30-35) kg/m(2). Iron deficiency was found in 42% of participants. Dietary intake of heme iron, found in meats, was favorably associated with 3 iron status biomarkers (ferritin, β = .366; sTfR:ferritin ratio, β = -.459; and total iron binding capacity, β = -18.26; all P<.05), independent of obesity-induced inflammation. Intake of vitamin C from food contributed to iron status (ferritin, β = .010 and sTfR:ferritin ratio, β = -.011; P<.05). Use of supplementary non-heme iron, at doses recommended for prophylaxis (45 mg/d), was positively associated with serum ferritin (β = .964; P = .029).

CONCLUSIONS

For patients who have undergone RYGB, consuming high, but realistic amounts of heme iron in meat, vitamin C from food, and adherence to recommended iron supplements can prevent iron deficiency.

Diagnosis and treatment of iron deficiency anemia during pregnancy and the postpartum period: Iron deficiency anemia working group consensus report

According to the World Health Organization (WHO), anemia is the most common disease, affecting >1.5 billion people worldwide. Furthermore, iron deficiency anemia (IDA) accounts for 50% of cases of anemia. IDA is common during pregnancy and the postpartum period, and can lead to serious maternal and fetal complications. The aim of this report was to present the experiences of a multidisciplinary expert group, and to establish reference guidelines for the optimal diagnosis and treatment of IDA during pregnancy and the postpartum period. Studies and guidelines on the diagnosis and treatment of IDA published in Turkish and international journals were reviewed. Conclusive recommendations were made by an expert panel aiming for a scientific consensus. Measurement of serum ferritin has the highest sensitivity and specificity for diagnosis of IDA unless there is a concurrent inflammatory condition. The lower threshold value for hemoglobin (Hb) in pregnant women is <11 g/dL during the 1^st and 3^rd trimesters, and <10.5 g/dL during the 2^nd trimester. In postpartum period a Hb concentration <10 g/dL indicates clinically significant anemia. Oral iron therapy is given as the first-line treatment for IDA. Although current data are limited, intravenous (IV) iron therapy is an alternative therapeutic option in patients who do not respond to oral iron therapy, have adverse reactions, do not comply with oral iron treatment, have a very low Hb concentration, and require rapid iron repletion. IV iron preparations can be safely used for the treatment of IDA during pregnancy and the postpartum period, and are more beneficial than oral iron preparations in specific indications.

Treatment for women with postpartum iron deficiency anaemia

BACKGROUND

Postpartum iron deficiency anaemia is caused by bleeding or inadequate dietary iron intake/uptake. This condition is defined by iron deficiency accompanied by a lower than normal blood haemoglobin concentration, although this can be affected by factors other than anaemia and must be interpreted in the light of any concurrent symptoms. Symptoms include fatigue, breathlessness, and dizziness. Treatment options include oral or intravenous iron, erythropoietin which stimulates red blood cell production, and substitution by red blood cell transfusion.

OBJECTIVES

To assess the efficacy and harms of the available treatment modalities for women with postpartum iron deficiency anaemia.

SEARCH METHODS

The Cochrane Pregnancy and Childbirth Group's Trials Register (9 April 2015); the WHO International Clinical Trials Registry Portal (ICTRP), and the Latin-American and Caribbean Health Sciences Literature database (LILACS) (8 April 2015) and reference lists of retrieved studies.

SELECTION CRITERIA

We included published, unpublished and ongoing randomised controlled trials that compared a treatment for postpartum iron deficiency anaemia with placebo, no treatment, or another treatment for postpartum iron deficiency anaemia, including trials described in abstracts only. Cluster-randomised trials were eligible for inclusion. We included both open-label trials and blinded trials, regardless of who was blinded. The participants were women with a postpartum haemoglobin of 120 g per litre (g/L) or less, for which treatment was initiated within six weeks after childbirth.Non-randomised trials, quasi-randomised trials and trials using a cross-over design were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, quality, and extracted data. We contacted study authors and pharmaceutical companies for additional information.

MAIN RESULTS

We included 22 randomised controlled trials (2858 women), most of which had high risk of bias in several domains. We performed 13 comparisons. Many comparisons are based on a small number of studies with small sample sizes. No analysis of our primary outcomes contained more than two studies.Intravenous iron was compared to oral iron in 10 studies (1553 women). Fatigue was reported in two studies and improved significantly favouring the intravenously treated group in one of the studies. Other anaemia symptoms were not reported. One woman died from cardiomyopathy (risk ratio (RR) 2.95; 95% confidence interval (CI) 0.12 to 71.96; two studies; one event; 374 women; low quality evidence). One woman developed arrhythmia. Both cardiac complications occurred in the intravenously treated group. Allergic reactions occurred in three women treated with intravenous iron, not statistically significant (average RR 2.78; 95% CI 0.31 to 24.92; eight studies; 1454 women; I² = 0%; low quality evidence). Gastrointestinal events were less frequent in the intravenously treated group (average RR 0.31; 95% CI 0.20 to 0.47; eight studies; 169 events; 1307 women; I² = 0%; very low quality evidence).One study evaluated red blood cell transfusion versus non-intervention. General fatigue improved significantly more in the transfusion group at three days (MD -0.80; 95% CI -1.53 to -0.07; women 388; low quality evidence), but no difference between groups was seen at six weeks. Maternal mortality was not reported.The remaining comparisons evaluated oral iron (with or without other food substances) versus placebo (three studies), intravenous iron with oral iron versus oral iron (two studies) and erythropoietin (alone or combined with iron) versus placebo or iron (seven studies). These studies did not investigate fatigue. Maternal mortality was rarely reported.

AUTHORS' CONCLUSIONS

The body of evidence did not allow us to reach a clear conclusion regarding the efficacy of the interventions on postpartum iron deficiency anaemia. The quality of evidence was low.Clinical outcomes were rarely reported. Laboratory values may not be reliable indicators for efficacy, as they do not always correlate with clinical treatment effects. It remains unclear which treatment modality is most effective in alleviating symptoms of postpartum anaemia.Intravenous iron was superior regarding gastrointestinal harms, however anaphylaxis and cardiac events occurred and more data are needed to establish whether this was caused by intravenous iron.The clinical significance of some temporarily improved fatigue scores in women treated with blood transfusion is uncertain and this modest effect should be balanced against known risks, e.g. maternal mortality (not reported) and maternal immunological sensitisation, which can potentially harm future pregnancies.When comparing oral iron to placebo it remains unknown whether efficacy (relief of anaemia symptoms) outweighs the documented gastrointestinal harms.We could not draw conclusions regarding erythropoietin treatment due to lack of evidence.Further research should evaluate treatment effect through clinical outcomes, i.e. presence and severity of anaemia symptoms balanced against harms, i.e. survival and severe morbidity.

Intravenous Iron Therapy in Patients with Iron Deficiency Anemia: Dosing Considerations

Objective. To provide clinicians with evidence-based guidance for iron therapy dosing in patients with iron deficiency anemia (IDA), we conducted a study examining the benefits of a higher cumulative dose of intravenous (IV) iron than what is typically administered. Methods. We first individually analyzed 5 clinical studies, averaging the total iron deficit across all patients utilizing a modified Ganzoni formula; we then similarly analyzed 2 larger clinical studies. For the second of the larger studies (Study 7), we also compared the efficacy and retreatment requirements of a cumulative dose of 1500 mg ferric carboxymaltose (FCM) to 1000 mg iron sucrose (IS). Results. The average iron deficit was calculated to be 1531 mg for patients in Studies 1-5 and 1392 mg for patients in Studies 6-7. The percentage of patients who were retreated with IV iron between Days 56 and 90 was significantly (p < 0.001) lower (5.6%) in the 1500 mg group, compared to the 1000 mg group (11.1%). Conclusions. Our data suggests that a total cumulative dose of 1000 mg of IV iron may be insufficient for iron repletion in a majority of patients with IDA and a dose of 1500 mg is closer to the actual iron deficit in these patients.

[Intravenous ferric carboxymaltose-associated hypophosphatemia in patients with iron deficiency anemia. A common side effect]

OBJECTIVES

To determine the frequency, severity, time of onset and factors associated with the development of hypophosphatemia (HF) in patients with iron deficiency anemia treated with intravenous ferric carboxymatose (ivFCM).

MATERIAL AND METHODS

Retrospective cohort study in patients iron deficiency anemia who received ivFCM and had an a prior and subsequent determination of serum phosphate. We carried out a comparative analysis between baseline and post-ivFCM levels of serum phosphate. In order to identify variables independently associated with HF a logistic regression analysis was also performed.

RESULTS

One hundred twenty-five patients were included. HF frequency was 58%. The median time to onset of HF was 18 days. Age, baseline ferritin levels and baseline phosphate levels were independently associated with the development of HF. The risk of HF in patients with baseline phosphate levels ≤ 3.1mg/dl was 67% higher than patients with ≥ 3.7 mg/dl.

CONCLUSIONS

ivFCM-associated HF is a frequent, early and, sometimes, prolonged effect in patients with iron deficiency anemia. Serum phosphate levels should be monitored after ivFCM administration, especially in older patients and in those with lower baseline phosphate or ferritin levels.

Iron therapy in anaemic adults without chronic kidney disease

BACKGROUND

Anaemia affects about a quarter of the world's population. An estimated 50% of anaemic people have anaemia due to iron deficiency.

OBJECTIVES

To assess the safety and efficacy of iron therapies for the treatment of adults with anaemia who are not pregnant or lactating and do not have chronic kidney disease.

SEARCH METHODS

We ran the search on 11 July 2013. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, EMBASE (Ovid SP), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) Plus (EBSCO Host), the Institute for Scientific Information Web of Science (ISI WOS) Scientific Citation Index (SCI)-EXPANDED (1970) and Conference Proceedings Citation Index (CPCI)-Science (1990) and Clinicaltrials.gov; we also screened reference lists. An updated search was run on 24 November 2014 but the results have not yet been incorporated into the review.

SELECTION CRITERIA

Two review authors independently selected references for further assessment by going through all titles and abstracts. Further selection was based on review of full-text articles for selected references.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted study data. We calculated the risk ratio (RR) with 95% confidence interval (CI) for binary outcomes and the mean difference (MD) or the standardised mean difference (SMD) with 95% CI for continuous outcomes. We performed meta-analysis when possible, when I(2) was less than or equal to 80% using a fixed-effect or random-effects model, using Review Manager software. The range of point estimates for individual studies is presented when I(2) > 80%.

MAIN RESULTS

We included in this systematic review 4745 participants who were randomly assigned in 21 trials. Trials were conducted in a wide variety of clinical settings. Most trials included participants with mild to moderate anaemia and excluded participants who were allergic to iron therapy. All trials were at high risk of bias for one or more domains. We compared both oral iron and parenteral iron versus inactive controls and compared different iron preparations.The comparison between oral iron and inactive control revealed no evidence of clinical benefit in terms of mortality (RR 1.05, 95% CI 0.68 to 1.61; four studies, N = 659; very low-quality evidence). The point estimate of the mean difference in haemoglobin levels in individual studies ranged from 0.3 to 3.1 g/dL higher in the oral iron group than in the inactive control group. The proportion of participants who required blood transfusion was lower with oral iron than with inactive control (RR 0.74, 95% CI 0.55 to 0.99; three studies, N = 546; very low-quality evidence). Evidence was inadequate for determination of the effect of parenteral iron on mortality versus oral iron (RR 1.49, 95% CI 0.56 to 3.94; 10 studies, N = 2141; very low-quality evidence) or inactive control (RR 1.04, 95% CI 0.63 to 1.69; six studies, N = 1009; very low-quality evidence). Haemoglobin levels were higher with parenteral iron than with oral iron (MD -0.50 g/dL, 95% CI -0.73 to -0.27; six studies, N = 769; very low-quality evidence). The point estimate of the mean difference in haemoglobin levels in individual studies ranged between 0.3 and 3.0 g/dL higher in the parenteral iron group than in the inactive control group. Differences in the proportion of participants requiring blood transfusion between parenteral iron and oral iron groups (RR 0.61, 95% CI 0.24 to 1.58; two studies, N = 371; very low-quality evidence) or between parenteral iron groups and inactive controls (RR 0.84, 95% CI 0.66 to 1.06; eight studies, N = 1315; very low-quality evidence) were imprecise. Average blood volume transfused was less in the parenteral iron group than in the oral iron group (MD -0.54 units, 95% CI -0.96 to -0.12; very low-quality evidence) based on one study involving 44 people. Differences between therapies in quality of life or in the proportion of participants with serious adverse events were imprecise (very low-quality evidence). No trials reported severe allergic reactions due to parenteral iron, suggesting that these are rare. Adverse effects related to oral iron treatment included nausea, diarrhoea and constipation; most were mild.Comparisons of one iron preparation over another for mortality, haemoglobin or serious adverse events were imprecise. No information was available on quality of life. Thus, little evidence was found to support the use of one preparation or regimen over another.Subgroup analyses did not reveal consistent results; therefore we were unable to determine whether iron is useful in specific clinical situations, or whether iron therapy might be useful for people who are receiving erythropoietin.

AUTHORS' CONCLUSIONS

• Very low-quality evidence suggests that oral iron might decrease the proportion of people who require blood transfusion, and no evidence indicates that it decreases mortality. Oral iron might be useful in adults who can tolerate the adverse events, which are usually mild.• Very low-quality evidence suggests that intravenous iron results in a modest increase in haemoglobin levels compared with oral iron or inactive control without clinical benefit.• No evidence can be found to show any advantage of one iron preparation or regimen over another.• Additional randomised controlled trials with low risk of bias and powered to measure clinically useful outcomes such as mortality, quality of life and blood transfusion requirements are needed.

Experience with intravenous ferric carboxymaltose in patients with iron deficiency anemia

Erythropoiesis may be limited by absolute or functional iron deficiency or when chronic inflammatory conditions lead to iron sequestration. Intravenous iron may be indicated when oral iron cannot address the deficiency. Ferric carboxymaltose (FCM) is a nondextran iron preparation recently approved in the United States for intravenous treatment of iron deficiency anemia (IDA) in adult patients with intolerance or unsatisfactory response to oral iron or with nondialysis-dependent chronic kidney disease. The full dose is two administrations of up to 750 mg separated by at least 7 days (up to 1500 mg total). FCM can be injected in 7-8 min or diluted in saline for slower infusion. The efficacy and safety of this dose was established in two prospective trials that randomized over 3500 subjects, 1775 of whom received FCM. One trial showed similar efficacy of FCM to an approved intravenous iron regimen (1000 mg of iron sucrose) in 2500 subjects with chronic kidney disease and additional cardiovascular risk factors. The other trial showed superior efficacy of FCM to oral iron in subjects with IDA due to various etiologies (e.g. gastrointestinal or uterine bleeding). In these trials, there was no significant difference between FCM and comparator with respect to an independently adjudicated composite safety endpoint, including death, myocardial infarction, or stroke. A database of 5799 subjects exposed to FCM provided a safety profile acceptable for regulatory approval. Mechanistic studies demonstrated that the transient, asymptomatic reduction in serum phosphate observed following FCM administration results from induction of fibroblast growth factor 23, which in turn induces renal phosphate excretion. An elevated hepcidin level may identify patients with IDA who will not respond to oral iron but will respond to FCM. The ability to administer FCM in two rapid injections or infusions will likely be viewed favorably by patients and healthcare providers.

Comparative review of the safety and efficacy of ferric carboxymaltose versus standard medical care for the treatment of iron deficiency anemia in bariatric and gastric surgery patients

BACKGROUND

Iron deficiency anemia (IDA) is a common finding in patients after bariatric surgery. The cause is multifactorial including reduced oral iron intake and malabsorption. While many patients can be managed with oral supplements, parenteral iron may be needed to restore and maintain iron stores.

METHODS

Subjects who had previous bariatric surgery and had participated in phase 3 industry-sponsored clinical trials designed to assess the safety and/or efficacy of intravenous (IV) ferric carboxymaltose (FCM) were retrospectively selected from the databases of each of these studies. Demographic data, efficacy measures [hemoglobin, ferritin, and transferrin saturation (TSAT)], and adverse events were compared between FCM and other agents utilized as comparators in the trials.

RESULTS

Two hundred eighty-one subjects from the intention to treat (ITT) population were included (mean age 49 years, BMI 33 kg/m(2), including 253 females). FCM had similar or improved efficacy (p < 0.05) in terms of increasing hemoglobin, ferritin, and TSAT values when compared to other iron products used as standard of care for IDA. The incidence of adverse events in the FCM patients (n = 123) versus patients receiving any IV iron (n = 126) was 61 and 56.3 %, respectively. The adverse events were similar in both groups with the exception of a transient decrease in serum phosphate which was observed more frequently in the FCM group.

CONCLUSIONS

These data in post-bariatric surgery IDA patients suggest that FCM is a safe and effective alternative to existing iron products permitting higher and thus less frequent individual doses.

Ferric carboxymaltose

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Direct Comparison of the Safety and Efficacy of Ferric Carboxymaltose versus Iron Dextran in Patients with Iron Deficiency Anemia

Several intravenous iron complexes are available for the treatment of iron deficiency anemia (IDA). Iron dextran (DEX) is associated with an elevated risk of potentially serious anaphylactic reactions, whereas others must be administered in several small infusions to avoid labile iron reactions. Ferric carboxymaltose (FCM) is a nondextran intravenous iron which can be administered in high single doses. A randomized, open label, and multicenter comparison of FCM to DEX in adults with IDA and baseline hemoglobin of ≤11.0 g/dL was conducted. A total of 160 patients were in the safety population (FCM n = 82; DEX n = 78). Adverse events, including immune system disorders (0% in FCM versus 10.3% in DEX, P = 0.003) and skin disorders (7.3% in FCM versus 24.4% in DEX, P = 0.004), were less frequently observed in the FCM group. A greater portion of patients in the FCM group experienced a transient, asymptomatic decrease in phosphate compared to patients in the DEX group (8.5% in FCM versus 0% in DEX, P = 0.014). In the FCM arm, the change in hemoglobin from baseline to the highest observed level was 2.8 g/dL, whereas the DEX arm displayed a change of 2.4 g/dL (P = 0.20). Treatment of IDA with FCM resulted in fewer hypersensitivity-related reactions than DEX.

Effects of iron deficiency anemia and its treatment on fibroblast growth factor 23 and phosphate homeostasis in women

Fibroblast growth factor 23 (FGF23) is an osteocyte-derived hormone that regulates phosphate and vitamin D homeostasis. Through unknown mechanisms, certain intravenous iron preparations induce acute, reversible increases in circulating FGF23 levels that lower serum phosphate in association with inappropriately low levels of calcitriol, similar to genetic diseases of primary FGF23 excess. In contrast, studies in wild-type mice suggest that iron deficiency stimulates fgf23 transcription but does not result in hypophosphatemia because FGF23 is cleaved within osteocytes by an unknown catabolic system. We tested the association of iron deficiency anemia with C-terminal FGF23 (cFGF23) and intact FGF23 (iFGF23) levels in 55 women with a history of heavy uterine bleeding, and assessed the longitudinal biochemical response over 35 days to equivalent doses of randomly-assigned, intravenous elemental iron in the form of ferric carboxymaltose (FCM) or iron dextran. Iron deficiency was associated with markedly elevated cFGF23 (807.8 ± 123.9 relative units [RU]/mL) but normal iFGF23 (28.5 ± 1.1 pg/mL) levels at baseline. Within 24 hours of iron administration, cFGF23 levels fell by approximately 80% in both groups. In contrast, iFGF23 transiently increased in the FCM group alone, and was followed by a transient, asymptomatic reduction in serum phosphate <2.0 mg/dL in 10 women in the FCM group compared to none in the iron dextran group. Reduced serum phosphate was accompanied by increased urinary fractional excretion of phosphate, decreased calcitriol levels, and increased parathyroid hormone levels. These findings suggest that iron deficiency increases cFGF23 levels, and that certain iron preparations temporarily increase iFGF23 levels. We propose that intravenous iron lowers cFGF23 in humans by reducing fgf23 transcription as it does in mice, whereas carbohydrate moieties in certain iron preparations may simultaneously inhibit FGF23 degradation in osteocytes leading to transient increases in iFGF23 and reduced serum phosphate.