Hypophosphatemia after intravenous iron therapy: Comprehensive review of clinical findings and recommendations for management

Evaluating the cost-utility of ferric derisomaltose versus ferric carboxymaltose in patients with inflammatory bowel disease and iron deficiency anaemia in Norway

AIMS

Iron deficiency anemia (IDA) is among the most common extraintestinal sequelae of inflammatory bowel disease (IBD). Intravenous iron is often the preferred treatment in patients with active inflammation with or without active bleeding, iron malabsorption, or intolerance to oral iron. The aim of the present study was to evaluate the cost-utility of ferric derisomaltose (FDI) versus ferric carboyxymaltose (FCM) in patients with IBD and IDA in Norway.

MATERIALS AND METHODS

A published patient-level simulation model was used to evaluate the cost-utility of FDI versus FCM in patients with IBD and IDA from a Norwegian national payer perspective. Iron need was modelled based on bivariate distributions of hemoglobin and bodyweight combined with simplified tables of iron need from the FDI and FCM summaries of product characteristics. Patient characteristics and disease-related quality of life data were obtained from the PHOSPHARE-IBD trial. Cost-utility was evaluated in Norwegian Kroner (NOK) over a five-year time horizon.

RESULTS

Patients required 1.64 fewer infusions of FDI than FCM over five years (5.62 versus 7.26), corresponding to 0.41 fewer infusions per treatment course. The reduction in the number of infusions resulted in cost savings of NOK 5,236 (NOK 35,830 with FDI versus NOK 41,066 with FCM). The need for phosphate testing in patients treated with FCM resulted in further cost savings with FDI (no costs with FDI versus NOK 4,470 with FCM). Total cost savings with FDI were therefore NOK 9,707. FDI also increased quality-adjusted life expectancy by 0.071 quality-adjusted life years (QALYs) driven by reduced incidence of hypophosphatemia and fewer interactions with the healthcare system.

CONCLUSIONS

FDI resulted in cost savings and improved quality-adjusted life expectancy versus FCM in patients with IDA and IBD in Norway. FDI therefore represents the economically preferable iron formulation in Norwegian patients with IBD and IDA in whom it is indicated.

Iron in Chronic Kidney Disease and End-Stage Kidney Disease-Current Trends and Future Direction

Anaemia is a frequent and serious complication in chronic kidney disease (CKD), affecting both non-dialysis-dependent (NDD) and dialysis-dependent (DD) patients. While erythropoietin (EPO) deficiency is the primary cause, iron deficiency (ID) also plays a crucial role. ID in CKD can be classified as either absolute, resulting from blood loss, or functional, driven by inflammation and elevated hepcidin levels, which trap iron in macrophages and hepatocytes, preventing its use in erythropoiesis. Elevated hepcidin also reduces dietary iron absorption in the gut, making oral iron supplements ineffective, particularly in advanced CKD. This review summarises the available intravenous (IV) iron formulations, discusses diagnostic definitions and treatment thresholds for ID in NDD and DD CKD, and explores potential future therapeutic directions.

How I treat iron-refractory iron deficiency anaemia-An expert opinion-based treatment guidance for children and adults

Iron-refractory iron deficiency anaemia (IRIDA) is a rare hereditary microcytic anaemia characterized by partial or complete resistance to oral iron supplementation, caused by elevated plasma hepcidin levels resulting from pathogenic variants in the TMPRSS6 gene. Although intravenous iron supplementation is often effective, patient responses can vary significantly due to various factors, and potential side effects of this treatment remain unclear. Additionally, evidence-based international guidelines for diagnosing and managing IRIDA are lacking. This review aims to provide patient-tailored treatment strategies, informed by case studies and expert opinion, to address the specific therapeutic needs of both children and adults with IRIDA.

Anemia in inflammatory bowel disease-A comprehensive review

Anemia is a frequent complication in inflammatory bowel disease (IBD) patients. The etiology is multifactorial, with iron deficiency and anemia of chronic disease being the main reasons. Other causes include vitamin B12 and folate deficiency, hemolytic anemia and medications such as azathioprine and sulfasalazine. Apart from physical symptoms, it is associated with several negative outcomes, including poor quality of life, increased risk of hospital admission, increased risk of surgery and higher treatment costs. Diagnostic evaluation aims to identify the underlying cause and severity to determine the appropriate therapeutic strategy. Investigations include a complete blood count, iron indices, inflammatory markers and vitamin B12 and folate levels. Patients with iron deficiency need adequate replacement therapy to improve hemoglobin and replenish iron stores. Those with moderate to severe anemia and/or active disease need intravenous iron, while mild anemia can be treated with oral iron. Multiple parenteral iron formulations are available which differ in dose and frequency of administration. Traditional oral iron supplements are available in ferrous forms, which, although effective, are associated with gastrointestinal side effects. Newer oral iron formulations have helped reduce these adverse effects but are expensive. Anemia of chronic disease is mainly driven by the effects of inflammatory mediators on iron metabolism and erythropoiesis and treatment requires control of disease activity. Relapse of anemia after therapy is frequent; hence, patients need to be closely followed up for early detection and appropriate management. Significant advances have been made in understanding the pathophysiology of anemia in IBD and better and safer iron formulations are available. However, a significant proportion of IBD patients with anemia go undetected or untreated and there is a need for improved recognition and better management practices. This review discusses various aspects of anemia in IBD and the current approach to diagnosis and management.

Ferric Carboxymaltose (FCM)-Associated Hypophosphatemia (HPP): A Systematic Review

BACKGROUND

Since 2015, ferric carboxymaltose (FCM), an intravenous (IV) iron formulation used for treating iron deficiency anemia (IDA), has been associated with an increasing number of reported hypophosphatemia (HPP) cases. Information on HPP clinical manifestations and incidence has not been reviewed.

METHODS

We reviewed HPP-associated adverse events reported to the FDA, case reports, case series, observational databases, clinical trials, meta-analyses, and FDA-approved labels. Our analysis found that FCM-associated HPP is a clinically important adverse drug reaction (ADR). The most common clinical manifestations are general weakness, fatigue, bone pain, muscle pain, osteomalacia, and fractures. Information on rates of FCM-associated HPP was from a review of clinical trials, observational databases, systematic reviews, and meta-analyses.

RESULTS

Clinical trials comparing FCM with other IV iron preparations identified FCM-associated HPP rates between 50% and 92% versus 2% and 8% with other IV iron formulations. Meta-analyses and systematic reviews confirmed these numbers. FDA-approved FCM labels do not include details of available ADR information in case reports, case series, observational databases, randomized trials, and meta-analyses.

CONCLUSION

We conclude that although the FDA-approved FCM Prescribing Label was updated in 2023, more robust recommendations on FCM-associated HPP are needed to prevent negative outcomes including osteomalacia and fractures. For patient safety, FCM label should advise monitoring serum phosphate levels prior to initiating first doses and before subsequent doses for all patients. Given differences between the FDA-approved FCM label and data reviewed herein, clinicians must be educated about FCM-associated HPP, difficulties treating HPP cases, and should consider administering other IV iron formulations that have lower rates of HPP.

Ferric carboxymaltose with or without phosphate substitution in iron deficiency or iron deficiency anemia before elective surgery - The DeFICIT trial

BACKGROUND

Iron deficiency anemia in the perioperative setting is treated predominantly with intravenous iron formulation, of which ferric carboxymaltose may induce hypophosphatemia by modulating fibroblast growth factor 23.

METHODS

In this single-center, prospective, randomized, double-blind trial, we consented 92 adult patients scheduled for elective major abdominal or thoracic surgery. These patients either had isolated iron deficiency (plasma ferritin <100 ng/mL or transferrin saturation < 20 %) or iron deficiency anemia (hemoglobin (Hb) 100-130 g/L with plasma ferritin <100 ng/mL or transferrin saturation < 20 %). Preoperatively, participants received a single preoperative intravenous dose of ferric carboxymaltose and were then randomly assigned to receive either phosphate or placebo, administered orally three times a day for 30 days corresponding to an 18 mmol dose of daily phosphate supplementation in the intervention group. The primary endpoint was the minimum serum phosphate concentration during follow-up visits. The key secondary efficacy endpoint was mean perioperative hemoglobin concentration of postoperative days 0, 2 and 4, assessing the non-inferiority of additional phosphate supplementation.

RESULTS

We randomly consented 46 patients in each group (mean ± SD age 56 ± 17 years, 57 % female). Minimal phosphate concentration was 0.49 ± 0.21 mmol/L in the treatment group and 0.42 ± 0.17 mmol/L in the placebo group (p = 0.12, two-sided p-value). Average mean hemoglobin was 110 ± 16 g/L in the treatment and 113 ± 13 g/L in the placebo group (p = 0.023, one-sided p-value for non-inferiority). Hypophosphatemia occurred in 32 patients (70 %) of the treatment group and in 39 patients (85 %) of the placebo group (odds ratio 0.15, 95 % CI from 0.02 to 0.77, p = 0.014). Secondary outcomes, such as rescue medication use, core muscle strength and MOCA test scores, did not differ between groups.

CONCLUSION

Co-administration of oral phosphate supplementation to ferric carboxymaltose cannot prevent hypophosphatemia. However, hypophosphatemia occurs in fewer patients. Phosphate co-administration did not impede the treatment of iron deficiency anemia with ferric carboxymaltose.

Gendered Experiences of Intravenous Iron Infusion Reactions: A Patient Perspective

Hypophosphatemia following iron infusion is thought to be a relatively rare complication of intravenous iron infusion, though research is beginning to demonstrate that it occurs more often than previously assumed. Still, healthcare professionals are often unaware of this potential complication. This, coupled with the medical bias women can receive in health settings-plus the over-representation of women receiving intravenous iron-means that symptoms of hypophosphatemia may be misinterpreted or worse, misdiagnosed. This article presents an account of a patient experience of hypophosphatemia following intravenous iron. Key points include: healthcare providers should be aware of this potential complication, healthcare providers must be prepared to listen, assess, address, and treat potential hypophosphatemia that occurs after receiving an iron infusion, and physicians should monitor phosphate, particularly in patients who develop fatigue, nausea, bone pain, and other symptoms of hypophosphatemia after receiving an iron infusion. Further research on the prevalence, impact, and duration of hypophosphatemia following iron infusion is needed.

Iron deficiency anaemia in a stable chronic intestinal failure cohort: Prevalence, associations and outcomes

BACKGROUND & AIMS

Current estimates of the prevalence of iron deficiency anaemia (IDA) in patients with chronic intestinal failure (CIF) exceed those seen in general population, however, the studies to-date are limited. The aim of this study was to determine the point prevalence of IDA in a large cohort of stable home parenteral nutrition (HPN) dependent adults managed by a specialist Intestinal Failure Unit.

METHODS

This was a retrospective cohort study of HPN-dependent adults managed by a national UK IF Reference Centre between 01/01/2019 and 31/12/2019. Patients with IDA were followed up until death or the end of the follow-up on 01/05/2024.

RESULTS

241 patients were included in the analysis. 27/241 (11.2 %) were diagnosed with IDA. Previous hypoferritinaemia, previous IDA and not receiving the recommended amount of iron via parenteral nutrition as per ESPEN guidelines were associated with higher likelihood of IDA diagnosis. Only 2/27 patients with IDA at inclusion fulfilled IDA criteria by the end of the follow up. Long-term outcomes in the patient cohort with IDA were good with no patients displaying evidence of malignancy until the end of the study period.

CONCLUSION

Our study shows that while IDA is common in patients with CIF, its clinical implications may differ from those in the general non-IF population. Further larger collaborative multi-centre research is necessary to confirm these findings with a view to develop evidence-based guidelines for the investigation of IDA in CIF.

Translating evidence into practice: Managing electrolyte imbalances and iron deficiency in heart failure

Mineral abnormalities are a common complication of heart failure (HF). In particular, dyskalaemia, hyponatraemia, and hypomagnesaemia are prevalent, with hypo- and hyperkalaemia observed in over 40 % of HF patients, hyponatraemia in 18-27 %, hypomagnesaemia in 7-52 %, and phosphate imbalance in 13 %. These abnormalities serve as indicators of the severity of HF and are strongly associated with an increased risk of morbidity and mortality. The neurohumoral activation, including the renin-angiotensin-aldosterone system (RAAS), the sympathetic nervous system, and vasopressin, HF medications such as diuretics and RAAS inhibitors, amd concomitant diseases such as chronic kidney disease, can disrupt mineral homeostasis. Iron deficiency (ID) is another of the most common mineral abnormalities, affecting up to 60 % of HF patients. ID is significantly associated with adverse clinical outcomes such as reduced quality of life and exercise capacity, HF re-hospitalization, and all-cause mortality. Various pathways contribute to the development of ID in HF, including reduced iron intake due to anorexia, increased hepcidin levels associated with chronic inflammation and hepatic congestion, and occult gastrointestinal bleeding due to the concomitant use of antithrombotic agents. The efficacy of iron replacement therapy has been demonstrated in clinical trials, particularly in heart failure with reduced ejection fraction (HFrEF), whilst more recently, it has also been shown to improve exercise capacity in patients with heart failure with preserved ejection fraction (HFpEF). This review focuses on potassium and phosphate abnormalities, hyponatraemia, hypomagnesaemia, and ID in HF, providing a comprehensive overview of the mechanisms, clinical significance, and intervention strategies with the latest findings.

Osteomalacia: A Challenging Diagnosis Adverse Event Associated with Intravenous Ferric Carboxymaltose-A Case Report

Hypophosphatemia resulting from intravenous iron treatment has become an increasingly concerning syndrome in recent years. We report the case of a 66-year-old male patient with a medical history of ankylosing spondylitis (AS), Crohn's disease, and chronic iron deficiency. Following intravenous iron infusions of ferric carboxymaltose, the patient developed diffuse bone pain and multiple bone fractures. After ruling out that the pain was in the context of spondyloarthritis (SpA), the diagnosis of osteomalacia associated with hypophosphatemia was established based on his clinical history, complementary analytical, and imaging tests. Once the diagnosis was made, intravenous ferric carboxymaltose infusions were discontinued, and oral calcium and vitamin D supplementation were initiated, resulting in clinical improvement with serum phosphate levels' normalization. This case shows the importance of recognizing the risk factors and clinical findings in selected patients, monitoring phosphate levels in those with high risk factors and considering stopping or switching to another intravenous iron formulation. Furthermore, this case highlights the importance of maintaining clinical suspicion of other possible etiologies of pain in patients with SpA.

Iron homeostasis in obesity and metabolic and bariatric surgery: a narrative review

Iron deficiency has been recognized as a potentially modifiable nutritional complication of metabolic and bariatric surgery (MBS) since prior to the turn of the century. Despite this, it remains the most common and clinically significant nutritional complication of this surgery with the potential to negate quality of life and the health benefits of surgical weight loss. This narrative review summarizes the current literature regarding iron deficiency as it relates to patients with severe obesity and those who undergo MBS. Advances in the clinical knowledge of iron homeostasis in severe obesity as a chronic disease, current diagnostic criteria for the diagnosis of iron deficiency in this patient population, the significance of preoperative iron deficiency, postoperative iron deficiency, and the status of supplementation and treatment will be reviewed with emphasis on gaps in knowledge and needed areas of further study.

In-depth clinical characterization of intravenous iron infusion-induced hypophosphatemic osteomalacia and its resolution

Iron deficiency anemia is treated by iron supplementation. Increasing evidence has shown that the carbohydrate components in iron infusions can cause hypophosphatemia and subsequent osteomalacia due to excess intact fibroblast growth factor 23 (iFGF23). We here undertook an in-depth characterization of 13 patients with iron infusion-induced osteomalacia (IIIO). Patients were characterized (monocentric institutional practice) by means of laboratory, bone density, HR-pQCT, and virtual osteoid volume estimation. We additionally report a patient who was treated with burosumab because iron infusions had to be continued despite osteomalacia. All 13 patients received ferric carboxymaltose (FCM) infusions and presented with low phosphate levels. Stopping the FCM infusions and supportive treatment by substitution of phosphate, calcium, native, and/or active Vitamin D was the chosen therapeutic approach. Pain, mobility, and biochemical data, such as serum phosphate levels, BMD, bone microstructure, and virtual osteoid volume, were the main outcome measures. Our results indicate biochemical normalization (eg, phosphate levels pre: 0.50 mmol/L ± 0.23 mmol/L, post: 0.93 mmol/L ± 0.32 mmol/L, p<.001) after stopping the FCM infusion and establishing supportive treatment. Additionally, pain levels on the visual analog scale (VAS) decreased (VASpre 7.31 ± 1.22, VASpost 2.73 ± 1.27, p<.0001) and areal BMD (expressed by T-score) improved significantly (T-scorepre: -1.85 ± 1.84, T-scorepost: -0.91 ± 2.13, p<.05). One patient requiring ongoing FCM infusions experienced significant additional benefits from burosumab treatment. In conclusion, our results highlight the importance of monitoring phosphate in patients treated with FCM infusions. Stopping FCM infusions is effective in addressing the excess of iFGF23 and thereby phosphate wasting. Supportive therapy enables quick recovery of the musculoskeletal system and improves pain levels in these patients.

Management of Iron Deficiency in Heart Failure: Practical Considerations and Implementation of Evidence-Based Iron Supplementation

Iron deficiency (ID) is present in approximately 50% of patients with heart failure (HF) and even higher prevalence rate up to 80% in post-acute HF setting. The current guidelines for HF recommend intravenous (IV) iron replacement in HF with reduced or mildly reduced ejection fraction and ID based on clinical trials showing improvements in quality of life and exercise capacity, and an overall treatment benefit for recurrent HF hospitalization. However, several barriers cause challenges in implementing IV iron supplementation in practice due, in part, to clinician knowledge gaps and limited resource availability to protocolize routine utilization in appropriate patients. Thus, the current review will discuss practical considerations in ID treatment, implementation of evidence-based ID treatment to improve regional health disparities with toolkits, inclusion/exclusion criteria of IV iron supplementation, and clinical controversies in ID treatment, as well as gaps in evidence and questions to be answered.

Recurrent Hypophosphatemia Following a Single Dose of Parenteral Iron Administration

Although parenteral iron is widely used to treat iron deficiency anemia (IDA), some side effects have been inadequately explored. Hypophosphatemia is becoming a well-documented, yet poorly understood, side effect of parenteral iron infusion, oftentimes causing serious and/or prolonged complications. In this article, we discuss the case of a 33-year-old female with IDA who suffered debilitating physical and mental symptoms of significant recurrent hypophosphatemia following a single standard dose of parenteral iron administration. Despite initial management with repeated parenteral and oral phosphate replacement, the hypophosphatemia, along with its symptoms and sequelae, persisted until active vitamin D supplementation with calcitriol was commenced following a multispecialty team decision. This case highlights the deficiencies in the recognition and management of parenteral iron-induced hypophosphatemia and proposes a requirement for standardization in its management strategies, including the use of vitamin D supplementation.

A Cost-Utility Analysis of Ferric Derisomaltose Versus Ferric Carboxymaltose in Patients with Iron Deficiency Anemia in China

INTRODUCTION

Intravenous (IV) iron is the recommended treatment for patients with iron deficiency anemia (IDA) unresponsive to oral iron treatment, in whom oral iron is contraindicated, or where rapid iron replenishment is required. Ferric derisomaltose (FDI) and ferric carboxymaltose (FCM) are high-dose, rapid-infusion, IV iron formulations that have recently been compared in three head-to-head randomized controlled trials (RCTs), which showed significantly higher incidence of hypophosphatemia after administration of FCM than FDI. The present study objective was to evaluate the cost-utility of FDI versus FCM in a population of patients with IDA in China.

METHODS

A previously-published patient-level simulation model was used to model the cost-utility of FDI versus FCM in China. The number of infusions of FDI and FCM was modeled based on the approved posology of the respective formulations using simplified tables of iron need in a population of patients with body weight and hemoglobin levels informed by a Chinese RCT of FCM. Data on the incidence of hypophosphatemia was obtained from the PHOSPHARE-IDA RCT, while data on disease-related quality of life were obtained from SF-36v2 data from the PHOSPHARE-IBD RCT.

RESULTS

Over the 5-year time horizon, patients received 3.98 courses of iron treatment on average, requiring 0.90 fewer infusions of FDI than FCM (7.69 vs. 6.79). This resulted in iron procurement and administration cost savings of renminbi (RMB) 206 with FDI (RMB 3,519 vs. RMB 3,312). Reduced incidence of hypophosphatemia-related fatigue resulted in an increase of 0.07 quality-adjusted life years and further cost savings of RMB 782 over 5 years, driven by reduced need for phosphate testing and replenishment. FDI was therefore the dominant intervention.

CONCLUSIONS

The results showed that FDI would improve patient quality of life and reduce direct healthcare expenditure versus FCM in patients with IDA in China.

Hypophosphatemia attenuates improvements in vitality after intravenous iron treatment in patients with inflammatory bowel disease

PURPOSE

Iron deficiency anemia is common in people with inflammatory bowel disease (IBD), causing deterioration in quality of life, which can be reversed by treatment that increases iron stores and hemoglobin levels. The present post hoc analyses estimate health state utility values for patients with IBD after treatment with ferric derisomaltose or ferric carboxymaltose and evaluate the health domains driving the changes.

METHODS

SF-36v2 responses were recorded at baseline and day 14, 35, 49, and 70 from 97 patients enrolled in the randomized, double-blind, PHOSPHARE-IBD trial (ClinicalTrials.gov ID: NCT03466983), in which patients with IBD across five European countries were randomly allocated to either ferric derisomaltose or ferric carboxymaltose. Changes in SF-36v2 scale scores and SF-6Dv2 health utility values were analyzed by mixed models.

RESULTS

In both treatment arms, SF-6Dv2 utility values and all SF-36v2 scale scores, except Bodily Pain, improved significantly (p =  < 0.0001). The improvement in SF-6Dv2 utility values showed no significant treatment group difference. The improvement in utility values was completely explained by improvement in Vitality scores. Vitality scores showed significantly larger improvement with ferric derisomaltose versus ferric carboxymaltose (p = 0.026). Patients with the smallest decrease in phosphate had significantly larger improvements in Vitality scores at each time point (p =  < 0.05 for all comparisons) and overall (p = 0.0006).

CONCLUSIONS

Utility values improved significantly with intravenous iron treatment. Improvement in utility values was primarily driven by Vitality scores, which showed significantly greater improvement in the ferric derisomaltose arm. Smaller decreases in phosphate were associated with significantly higher Vitality scores, suggesting that quality of life improvement is attenuated by hypophosphatemia. The utility values can inform future cost-utility analysis.

Iron and bones: effects of iron overload, deficiency and anemia treatments on bone

Iron is a vital trace element and exerts opposing effects on bone in both iron overload and iron deficiency situations. Remarkably, iron supplementation through intravenous infusion in patients with iron deficiency can also have detrimental effects on bone in special cases. The diverse mechanisms underlying these effects and their manifestations contribute to the complexity of this relationship. Iron overload impacts both bone resorption and formation, accelerating bone resorption while reducing bone formation. These effects primarily result from the direct action of reactive oxygen species (ROS), which influence the proliferation, differentiation, and activity of both osteoclasts and osteoblasts differently. This imbalance favors osteoclasts and inhibits the osteoblasts. Simultaneously, multiple pathways, including bone morphogenic proteins, RANK ligand, and others, contribute to these actions, leading to a reduction in bone mass and an increased susceptibility to fractures. In contrast, iron deficiency induces low bone turnover due to energy and co-factor deficiency, both of which require iron. Anemia increases the risk of fractures in both men and women. This effect occurs at various levels, reducing muscular performance and, on the bone-specific level, decreasing bone mineral density. Crucially, anemia increases the synthesis of the phosphaturic hormone iFGF23, which is subsequently inactivated by cleavage under physiological conditions. Thus, iFGF23 levels and phosphate excretion are not increased. However, in specific cases where anemia has to be managed with intravenous iron treatment, constituents-particularly maltoses-of the iron infusion suppress the cleavage of iFGF23. As a result, patients can experience severe phosphate wasting and, consequently, hypophosphatemic osteomalacia. This condition is often overlooked in clinical practice and is often caused by ferric carboxymaltose. Ending iron infusions or changing the agent, along with phosphate and vitamin D supplementation, can be effective in addressing this issue.

Intravenous ferric carboxymaltose is associated with lowering of plasma phosphate levels in patients with gastric bypass surgery: a retrospective case series

AIMS

Bariatric surgery induces several micronutrient deficiencies that require supplementation. For iron, parenteral infusions are usually preferred over oral supplementation. Ferric carboxymaltose infusion has been associated with hypophosphataemia, mostly transient and asymptomatic. However, in some cases, ferric carboxymaltose-induced hypophosphataemia may persist for weeks to months and may induce muscle weakness, osteomalacia and bone fractures. The aim of this study was to identify possible predictors of a clinically relevant decrease in serum phosphate after ferric carboxymaltose infusion in patients with previous Roux-en-Y gastric bypass.

METHODS

Patients with previous Roux-en-Y gastric bypass who received ferric carboxymaltose infusions between January 2018 and September 2019 and had recorded phosphataemia before and after ferric carboxymaltose infusion at the Lausanne University Hospital, Lausanne, Switzerland, were studied retrospectively. A multiple linear regression model was built with delta phosphataemia as the outcome to investigate the factors related to magnitude of serum phosphate lowering.

RESULTS

Seventy-seven patients (70 females and 7 males) with previous Roux-en-Y gastric bypass were studied. Mean age (SD) was 43.2 (10.7) years and median BMI was 30.9 kg/m2 (IQR 27.9-36.4). Sixty-eight patients (88.3%) received an infusion of 500 mg ferric carboxymaltose and 9 patients (11.7%) received 250 mg ferric carboxymaltose. Forty-nine patients (63.6%) developed hypophosphataemia (<0.8 mmol/l) after ferric carboxymaltose infusion. Median plasma phosphate significantly decreased by 0.33 mmol/l (IQR 0.14-0.49) (p<0.0001). Multiple linear regression identified the ferric carboxymaltose dose as the only risk factor significantly associated with the magnitude of serum phosphate lowering, with an additional mean loss of 0.26 mmol/l with a 500 mg infusion compared to a 250 mg infusion (p = 0.020).

CONCLUSION

Ferric carboxymaltose infusions substantially decreased plasma phosphate levels in patients with previous Roux-en-Y gastric bypass. Compared to a dose of 250 mg, infusion of a dose of 500 mg ferric carboxymaltose decreased the plasma phosphate further in this population.

Expert consensus guidelines: Intravenous iron uses, formulations, administration, and management of reactions

Intravenous iron has become an essential component for the treatment of iron deficiency and iron deficiency anemia. Individuals administering Intravenous iron should have knowledge in intravenous iron administration, including a pre-infusion assessment to evaluate infusion reaction risks, pre- and post-infusion monitoring, identification of and management of infusion reactions, accurate documentation of these reactions, laboratory monitoring and recognition and management of treatment-emergent hypophosphatemia. This comprehensive consensus provides step-by-step guidance and tools for practitioners to promote safe delivery of intravenous iron, recognition, and management of infusion reactions and treatment-emergent hypophosphatemia.

Ferric carboxymaltose-induced hypophosphatemia - a case series

Hypophosphatemia may cause serious complications. Depending on its severity and duration, signs and symptoms range from fatigue to life-threatening events, like severe rhabdomyolysis and mental status changes. Long-term consequences include osteomalacia. Hypophosphatemia may be secondary to the use of parental iron, mostly associated with ferric carboxymaltose (FCM), with an incidence of around 45% to 70%. We describe three cases of hypophosphatemia in patients with chronic iron deficiency anemia, requiring repeated FCM infusions. The patients' presentation to the Rheumatology department included musculoskeletal symptoms of severe hypophosphatemia and long-term hypophosphatemic osteomalacia, with fractures. We aim to raise awareness for ferric carboxymaltose-induced hypophosphatemia, an entity increasingly described in the literature that can be responsible for severe disability or potentially life-threatening adverse events.

Intravenous iron-induced hypophosphatemia and kidney stone disease

Patients with Crohn's disease are at increased risk for symptomatic nephrolithiasis. Stones in these patients are most commonly composed of calcium oxalate monohydrate or mixed calcium-oxalate and calcium-phosphate. Precipitation of both minerals depends on urinary pH, calcium, phosphate and oxalate excretion. The present manuscript reports on two patients with Crohn's disease and bowel resection, in whom the onset of symptomatic urolithiasis occurred after repeated infusions of ferric carboxymaltose - a drug, which is known to cause hyperphosphaturia. The present study shows that ferric carboxymaltose-induced hyperphosphaturia can be associated with kidney stone formation and symptomatic urolithiasis, especially in patients treated with calcitriol. Calcitriol has been shown to mitigate ferric carboxymaltose-induced secondary hyperparathyroidism and hyperphosphaturia, but is known to increase urinary calcium excretion. Chemical analysis of recovered stones revealed that they were mixed calcium oxalate and phosphate stones. Ring-like deposition of iron detected by spatially resolved elemental analysis using laser ablation-inductively coupled plasma mass spectrometry, showed that the stones also contained iron. Based on our findings, we propose that patients with inflammatory bowel disease requiring intravenous iron therapy should be carefully monitored for the development of hypophosphatemia and urolithiasis. If hypophosphatemia occurs in such patients, calcitriol should be used with caution.

Intravenous iron in patients with iron deficiency and heart failure: a review of modern evidence

PURPOSE OF REVIEW

Iron deficiency is common in patients with heart failure, affecting up to half of ambulatory patients and an even greater percentage of patients admitted for acute decompensation. Iron deficiency in this population is also associated with poor outcomes, including worse quality of life in addition to increased hospitalizations for heart failure and mortality. Evidence suggests that patients with iron deficiency in heart failure may benefit from repletion with IV iron.

RECENT FINDINGS

In this review, we outline the etiology and pathophysiology of iron deficiency in heart failure as well as various iron formulations available. We discuss evidence for intravenous iron repletion with a particular focus on recent studies that have evaluated its effects on hospitalizations and mortality. Finally, we discuss areas of uncertainty and future study and provide practical guidance for iron repletion.

SUMMARY

In summary, there is overwhelming evidence that intravenous iron repletion in patients with iron deficiency in heart failure is both beneficial and safe. However, further evidence is needed to better identify which patients would most benefit from iron repletion as well as the ideal repletion strategy.

The differential effect of modern intravenous iron on fibroblast growth factor 23 and phosphate in non-dialysis dependent CKD - the exploratory randomized controlled double-blind ExplorIRON-CKD study

BACKGROUND

Intravenous iron is commonly used in patients with non-dialysis-dependent chronic kidney disease (CKD). Modern intravenous iron compounds (e.g. ferric derisomaltose (FDI), ferric carboxymaltose (FCM)) are increasingly utilized with similar efficacy. A differential effect in terms of hypophosphatemia has been noted following administration of FCM, which may be related to fibroblast growth factor 23 (FGF23). This study was designed to examine the comparative effects of FDI and FCM on FGF23, phosphate and other markers of bone turnover.

METHODS

The single-center double-blind randomized controlled trial "Iron and Phosphaturia - ExplorIRON-CKD" primarily assessed the effects of FCM and FDI on intact FGF23 and phosphate, whilst also studying the impact on vitamin D, parathyroid hormone and phosphaturia. Bone markers including alkaline phosphatase, bone-specific alkaline phosphatase, procollagen type 1 N-terminal propeptide and carboxy-terminal collagen cross-linked telopeptide were monitored. Non-dialysis-dependent CKD patients (stage 3a-5) with iron deficiency with/without anemia (serum ferritin < 200 µg/L or transferrin saturation = 20% and serum ferritin 200-299 µg/L) were randomized to receive FDI or FCM in a 1:1 ratio. At baseline 1000 mg of intravenous iron was administered followed by 500-1000 mg at 1 month to achieve replenishment. Measurements were performed at baseline, 1-2 days following iron administration, 2 weeks, 1 month (second iron administration), 1-2 days following second administration, 2 months and 3 months following initial infusion.

RESULTS

Twenty-six patients participated in the trial; 14 randomized to FDI and 12 to FCM. Intact FGF23 increased following administration of iron, and the increase was significantly higher with FCM compared to FDI (Baseline to 1-2 days following 1st administration: FDI: 3.0 (IQR: - 15.1 - 13.8) % vs. FCM: 146.1 (IQR: 108.1-203.1) %; p < 0.001 and Baseline to 1-2 days following 2nd administration: FDI: 3.2 (IQR: - 3.5 - 25.4) % vs. FCM: 235.1 (138.5-434.6) %; p = 0.001). Phosphate levels decreased in the FCM group, causing a significant difference versus FDI 2 weeks following administration of the first dose. A significantly greater decrease in 1,25 (OH)2 Vitamin D was noted with FCM. Several markers of bone turnover significantly changed following administration of FCM but not FDI.

CONCLUSIONS

The study suggests a differential effect on FGF23 following administration of FCM compared to FDI in non-dialysis-dependent CKD patients, similar to other patient groups. This may lead to changes consistent with hypovitaminosis D and alterations in bone turnover with potential clinical consequences. Further definitive studies are required to understand these differences of intravenous iron compounds.

TRIAL REGISTRATION

European Union Drug Regulating Authorities Clinical Trials Database (EudraCT) number: 2019-004370-26 ( https://www.clinicaltrialsregister.eu/ctr-search/trial/2019-004370-26/GB ) (First date of trial registration: 03/12/2019).

Intravenous iron: an update

Iron deficiency is the most common nutritional deficiency worldwide, with significant adverse health consequences in the presence or absence of anaemia. Total dose intravenous iron replacement is recommended for replacement of iron in patients with severe iron deficiency, especially in the presence of anaemia, intolerance or inefficacy following oral iron, or states of inflammation where upregulation of hepcidin may impair gastrointestinal absorption of iron. Currently, available intravenous iron formulations have been demonstrated to have an excellent overall safety profile, but potential adverse effects, including skin staining, infusion-related reactions and hypophosphataemia, have been described. Knowledge of differences in administration and safety profiles of currently available iron formulations will allow appropriate prescription, counselling, as well as recognition and management of adverse events in patients requiring intravenous iron.

Mineral Supplements in Ageing

With advancing age, achievement of dietary adequacy for all nutrients is increasingly difficult and this is particularly so for minerals. Various factors impede mineral acquisition and absorption including reduced appetite, depressed gastric acid production and dysregulation across a range of signalling pathways in the intestinal mucosa. Minerals are required in sufficient levels since they are critical for the proper functioning of metabolic processes in cells and tissues, including energy metabolism, DNA and protein synthesis, immune function, mobility, and skeletal integrity. When uptake is diminished or loss exceeds absorption, alternative approaches are required to enable individuals to maintain adequate mineral levels. Currently, supplementation has been used effectively in populations for the restoration of levels of some minerals like iron, zinc, and calcium, but these may not be without inherent challenges. Therefore, in this chapter we review the current understanding around the effectiveness of mineral supplementation for the minerals most clinically relevant for the elderly.

Pharmacological Treatment of Heart Failure: Recent Advances

BACKGROUND

Heart failure is a clinical condition with high mortality and morbidity that occurs when the heart is unable to pump enough blood to meet the metabolic demands of the body. The pharmacological management of heart failure has been revolutionized over the past decade with novel treatments.

OBJECTIVE

The aim of the review is to highlight the recent pharmacological advances in the management of heart failure.

RESULTS

Sodium-glucose cotransporter-2 inhibitor (SGLT2i), iron carboxymaltose, finerenone, omecamtiv mecarbil, and vericiguat have been shown to reduce hospitalization for heart failure. However, only SGLT2i, vericiguat, and omecamtiv mecarbil have been shown to reduce cardiovascular death. Finerenone has been shown to reduce cardiovascular events and renal adverse outcomes in patients with diabetes and kidney disease. Currently, only SGLT2i has been studied in patients beyond the heart failure with reduced ejection fraction population.

CONCLUSION

The current quadruple therapy in the treatment of heart failure has demonstrated a reduction in the hospitalization of patients and a decrease in mortality associated with the condition. Individualized heart failure therapy research have shown some benefit in select heart failure patients. Further research on novel therapies will help improve heart failure patient outcomes.

Cost-utility analysis of ferric derisomaltose versus ferric carboxymaltose in patients with inflammatory bowel disease and iron deficiency anemia in England

AIMS

Anemia is the most common extraintestinal complication of inflammatory bowel disease (IBD), with approximately half of cases caused by iron deficiency (ID). Intravenous iron is the preferred ID anemia (IDA) treatment where oral iron is contraindicated, ineffective or not tolerated, or where ID correction is urgent. The objective was to evaluate the cost-utility of ferric derisomaltose (FDI) versus ferric carboxymaltose (FCM) in patients with IBD and IDA in England, in whom IV iron treatment is preferred.

MATERIALS AND METHODS

A patient-level simulation model was developed, capturing quality of life (QoL) differences based on SF-36v2 data from the PHOSPHARE-IBD randomized controlled trial, monitoring and incidence of post-infusion hypophosphatemia, and number of iron infusions required. Analyses were conducted over a five-year time horizon from the Department of Health and Social Care (DHSC) perspective, with healthcare provider and societal perspectives adopted in separate analyses. Future costs and effects were discounted at 3.5% per annum and one-way and probabilistic sensitivity analyses were performed.

RESULTS

FDI increased quality-adjusted life expectancy by 0.075 QALYs versus FCM from 2.57 QALYs to 2.65 QALYs per patient. Patients receiving FDI required 1.63 fewer iron infusions over the five-year time horizon, driving infusion-related cost savings of GBP 496 per patient (GBP 2,188 versus GBP 1,692) from the DHSC perspective. Costs of monitoring and treating hypophosphatemia after FCM were GBP 226, yielding total savings of GBP 722 per patient (GBP 2,414 versus GBP 1,692) over the five-year time horizon. FDI also led to reduced costs versus FCM in the societal and provider analyses and was therefore the dominant intervention across all three perspectives.

LIMITATIONS

The analysis did not capture patient adherence, hypophosphatemic osteomalacia, or fractures.

CONCLUSIONS

Results showed that FDI improved patient QoL and reduced direct healthcare expenditure versus FCM in patients with IBD and IDA in England.

[Hypophosphatemia associated with use of intravenous ferric carboxymaltose]

Introduction

Introduction: ferric carboxymaltose (CF) is an intravenous preparation that helps the rapid correction of anemia with a lower risk of adverse reactions. However, an association has been found between the administration of CF and the development of hypophosphatemia. Case report: we present the clinical case of a 57-year-old patient with a history of iron de-ficiency anemia who, after receiving treatment with CF (Ferinjet®) chronically, develops a clinical of severe muscle weakness. Laboratory tests showed hypophosphatemia, normocalcemia, normal vitamin D level (after correction) and increased renal excretion of phosphorus. After study, the diagnosis of chronic hypophosphatemia secondary to the use of CF is reached. Discussion: CF can cause an increase in FGF-23 which acts at the renal level inducing phosphaturia, which can generate severe hypophosphatemia. This case demonstrates the importance of recognizing and treating this clinical entity in time.

Hypophosphatemia related to intravenous iron therapy with ferric carboxymaltose: A case series

OBJECTIVES

This case series would like to highlight hypophosphatemia related to ferric carboxymaltose and its adverse clinical consequences.

BACKGROUND

Intravenous iron supplementation is a good alternative to oral iron replacement in iron deficiency anaemia due to its ability to correct iron deficit with minimal infusions without incurring the gastrointestinal side effects of oral iron replacement. Ferric carboxymaltose is one common formula for intravenous iron supplementation. However, an increasingly recognised adverse side-effect of intravenous ferric carboxymaltose is hypophosphatemia. There has been increasing reports and studies highlighting hypophosphatemia related to intra-venous iron therapy. Though initially thought to be transient and asymptomatic, recent studies have shown that persistent hypophosphatemia in iron therapy can result in debilitating disease including myopathy, fractures and osteomalacia.

METHODS

A retrospective analysis of all patients who had ferric carboxymaltose was performed.

RESULTS

We highlight 3 cases where hyposphatemia affected the clinical outcomes.

CONCLUSION

With the increased use of IV iron it is important to be aware of the high potential for hypophosphatemia secondary to ferric carboxymaltose.

The effect of iron therapy on oxidative stress and intestinal microbiota in inflammatory bowel diseases: A review on the conundrum

One in five patients with Inflammatory Bowel Disease (IBD) suffers from anemia, most frequently caused by iron deficiency. Anemia and iron deficiency are associated with worse disease outcomes, reduced quality of life, decreased economic participation, and increased healthcare costs. International guidelines and consensus-based recommendations have emphasized the importance of treating anemia and iron deficiency. In this review, we draw attention to the rarely discussed effects of iron deficiency and iron therapy on the redox status, the intestinal microbiota, and the potential interplay between them, focusing on the clinical implications for patients with IBD. Current data are scarce, inconsistent, and do not provide definitive answers. Nevertheless, it is imperative to rule out infections and discern iron deficiency anemia from other types of anemia to prevent untargeted oral or intravenous iron supplementation and potential side effects, including oxidative stress. Further research is necessary to establish the clinical significance of changes in the redox status and the intestinal microbiota following iron supplementation.

Bone marrow sinusoidal endothelial cells are a site of Fgf23 upregulation in a mouse model of iron deficiency anemia

Iron deficiency is a potent stimulator of fibroblast growth factor 23 (FGF23), a hormonal regulator of phosphate and vitamin D metabolism, that is classically thought to be produced by bone-embedded osteocytes. Here, we show that iron-deficient transmembrane serine protease 6 knockout (Tmprss6-/-) mice exhibit elevated circulating FGF23 and Fgf23 messenger RNA (mRNA) upregulation in the bone marrow (BM) but not the cortical bone. To clarify sites of Fgf23 promoter activity in Tmprss6-/- mice, we introduced a heterozygous enhanced green fluorescent protein (eGFP) reporter allele at the endogenous Fgf23 locus. Heterozygous Fgf23 disruption did not alter the severity of systemic iron deficiency or anemia in the Tmprss6-/- mice. Tmprss6-/-Fgf23+/eGFP mice showed green fluorescence in the vascular regions of BM sections and showed a subset of BM endothelial cells that were GFPbright by flow cytometry. Mining of transcriptomic data sets from mice with normal iron balance revealed higher Fgf23 mRNA in BM sinusoidal endothelial cells (BM-SECs) than that in other BM endothelial cell populations. Anti-GFP immunohistochemistry of fixed BM sections from Tmprss6-/-Fgf23+/eGFP mice revealed GFP expression in BM-SECs, which was more intense than in nonanemic controls. In addition, in mice with intact Tmprss6 alleles, Fgf23-eGFP reporter expression increased in BM-SECs following large-volume phlebotomy and also following erythropoietin treatment both ex vivo and in vivo. Collectively, our results identified BM-SECs as a novel site for Fgf23 upregulation in both acute and chronic anemia. Given the elevated serum erythropoietin in both anemic models, our findings raise the possibility that erythropoietin may act directly on BM-SECs to promote FGF23 production during anemia.

Incidence and predictors of hypophosphataemia after ferric carboxymaltose use-A 3-year experience from a single institution in Singapore

Ferric carboxymaltose (FCM) administration helps reduce transfusion requirements in the perioperative situation, which improves patient outcomes and reduces healthcare costs. However, there is increasing evidence of hypophosphataemia after FCM use. We aim to determine the incidence of hypophosphataemia after FCM administration and elucidate potential biochemical factors associated with the development of subsequent hypophosphataemia. A retrospective review of anonymised data of all FCM administrations in a single institution was conducted from August 2018 to August 2021. Each unique FCM dose administered was examined to assess its effect on Hb and serum phosphate levels within the subsequent 28 days from each FCM administration. Phosphate levels were repeatedly measured within the 28-day interval and the lowest phosphate level within that period was determined. Patients' serum phosphate levels within 28 days of FCM administration were compared against normal serum phosphate levels within 2 weeks before FCM administration. The odds ratios of various pre-FCM serum markers were calculated to elucidate potential biochemical predictors of post-FCM hypophosphataemia. In 3 years, a total of 1296 doses of FCM were administered to 1069 patients. The mean improvement in Hb was 2.45 g/dL (SD = 1.94) within 28 days of FCM administration, with the mean time taken to peak Hb levels being 6.3 days (SD = 8.63), which is earlier than expected, but was observed in this study and hence reported. The incidence of hypophosphataemia <0.8 mmol/L was 22.7% (n = 186), and <0.4 mmol/L was 1.6% (n = 9). This figure is lower than the numbers reported in previously published meta-analyses given that routine checks of serum phosphate levels were not conducted initially and hence could possibly be higher. The odds of developing hypophosphataemia (<0.8 mmol/L) were 27.7 (CI: 17.3-44.2, p < 0.0001) if baseline serum phosphate was less than 1 mmol/L. The odds of developing hypophosphataemia (<0.8 mmol/L) were 1.3 (CI: 1.08-1.59, p < 0.01) if the change in Hb levels observed after FCM administration were more than 4 g/dL. Hypophosphataemia after FCM administration is significant and FCM should be used by clinicians with caution.

Hypophosphatemic osteomalacia induced by intravenous iron therapy: a case report

OBJECTIVE

Osteomalacia is an uncommon, overlooked and debilitating metabolic bone disease with numerous aetiologies. Herein, we report an atypical cause of osteomalacia - intravenous iron therapy.

METHODS

Description of a case report of hypophophatemic osteomalacia induced by ferric carboxymaltose infusions.

RESULTS

A 70-year-old male with Rendu-Osler-Weber syndrome requiring repeated infusions of ferric carboxymaltose was admitted for disabling lower limb pain associated with persistent hypophosphatemia (1.6mg/dL) and increased urinary fractional excretion of phosphate (43%, UP04=118.3mg/dL), serum fibroblast growth factor 23 (324UA/mL), intact parathyroid hormone (110pg/mL) and bone alkaline phosphatase (40.1mcg/L). X-ray and CT of the feet showed severe diffuse bone demineralization. Feet MRI displayed a subchondral fracture of the cuneiform-navicular joints. Spine X-ray revealed dorsolumbar vertebral flattening. Somatostatin receptor PET scan excluded an occult tumor. Bone biopsy with histomorphometry confirmed the presence of osteomalacia. After excluding other causes, a diagnosis of hypophosphatemic osteomalacia induced by frequent ferric carboxymaltose infusions was made. The iron formulation was replaced by saccharated ferric oxide infusions and progressive titration of calcitriol up to 1.5mg/day and oral disodium phosphate up to 5740mg/day was started. After 6 months, there was a clear clinical and analytical improvement.

CONCLUSION

Osteomalacia may be a consequence of prolonged hypophosphatemia induced by recurrent ferric infusions, which is an uncommon and neglected bone adverse event of this therapy. Phosphate levels and bone symptoms should be monitored during repetitive iron infusions, maintaining a high level of suspicion for osteomalacia as it is important to identify and treat it in a timely manner, minimizing its severe morbidity.

[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.

What is wrong in doing good?

Hypophosphataemia is a common side-effect in patients with iron deficiency anaemia treated with ferric carboxymaltose, which is not a class effect of all intravenous (IV) iron formulations. The report by Chu et al. shows that moderate and severe hypophosphataemia is common and can even require IV supplementation of phosphate with unknown long-term consequences. Commentary on: Chu et al. Incidence and predictors of hypophosphataemia after ferric carboxymaltose use-a 3-year experience from a single institution in Singapore. Br J Haematol 2023;202:1199-1204.

Multifocal Abscesses, Necrotizing Fasciitis, Iron Deficiency Anemia, and Hypophosphatemia Induced by Ferric Carboxymaltose Infusions: Report of a Case of Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant vascular dysplasia in which disrupted angiogenesis leads to increased formation of mucocutaneous telangiectasias or major vascular malformations. Iron deficiency anemia and recurrent abscesses are commonly reported in these patients, reinforcing screening and targeted therapies for these conditions. We report a 50-year-old man with HHT affected by repeated episodes of iron deficiency anemia secondary to recurrent epistaxis requiring frequent intravenous iron infusions. He eventually developed hypophosphatemia and hyperphosphaturia secondary to ferric carboxymaltose. He also had a history of recurrent multifocal abscesses, including a severe presentation of necrotizing fasciitis, requiring multiple surgical interventions. Despite the identification of hypogammaglobulinemia, only after consistent dental treatment and antibiotic prophylaxis did the abscesses stop recurring. We highlight the need for careful consideration of all possible complications inherent to the disease itself but also those related to comorbidities or existing treatments.

Impact of Intravenous Iron Substitution on Serum Phosphate Levels and Bone Turnover Markers-An Open-Label Pilot Study

The association between intravenous iron substitution therapy and hypophosphatemia was previously reported in patients with iron deficiency anemia. However, the extent of hypophosphatemia is thought to depend on the type of iron supplementation. We hypothesized that the intravenous application of ferric carboxymaltose and iron sucrose leads to a different longitudinal adaptation in serum phosphate levels. In this open-label pilot study, a total of 20 patients with inflammatory bowel diseases or iron deficiency anemia were randomly assigned to one of two study groups (group 1: ferric carboxymaltose, n = 10; group 2: iron sucrose, n = 10). Serum values were controlled before iron substitution therapy, as well as 2, 4, and 12 weeks after the last drug administration. The primary objective of the study was the longitudinal evaluation of serum phosphate levels after iron substitution therapy with ferric carboxymaltose and iron sucrose. The secondary objective was the longitudinal investigation of calcium, 25-hydroxyvitamin D (25(OH)D), intact parathyroid hormone, procollagen type 1 amino-terminal propeptide (P1NP), beta-CrossLaps (CTX), hemoglobin (Hb), iron, ferritin, and transferrin saturation levels. Two weeks after drug administration, phosphate levels were significantly lower (p < 0.001) in group 1 and ferritin levels were significantly higher (p < 0.001) in group 1. Phosphate levels (0.8-1.45 mmol/L) were below the therapeutic threshold and ferritin levels (10-200 ng/mL for women and 30-300 ng/mL for men) were above the therapeutic threshold in group 1. P1NP (15-59 µg/L) and CTX (<0.57 ng/mL) levels were above the therapeutic threshold in group 2. Four weeks after drug administration, significant differences were still observed between both study groups for phosphate (p = 0.043) and ferritin (p = 0.0009). All serum values except for Hb were within the therapeutic thresholds. Twelve weeks after drug administration, no differences were observed in all serum values between both study groups. Hb values were within the therapeutic threshold in both study groups. Serum 25(OH)D levels did not differ between both study groups throughout the whole study period and remained within the therapeutic threshold.

Hypophosphataemia risk associated with ferric carboxymaltose in heart failure: A pooled analysis of clinical trials

AIMS

Iron deficiency is a common finding among patients with heart failure (HF) and is associated with adverse outcomes, including decreased quality of life, increased risk of hospitalization, and decreased survival. Intravenous ferric carboxymaltose (FCM) has been shown to improve outcomes among patients with HF and concomitant iron deficiency, but FCM is associated with an increased risk of hypophosphataemia. We aimed to better characterize this risk among HF populations.

METHODS AND RESULTS

This pooled analysis examined data from 41 studies of adults with iron deficiency across disease states and therapeutic areas. Among the 7931 patients treated with FCM available for analysis, 14% made up the HF subgroup. Additional subgroups included women's health (36%), non-dialysis-dependent chronic kidney disease (NDD-CKD; 27%), haemodialysis-dependent chronic kidney disease (HD-CKD; 1%), gastrointestinal (10%), neurology (3%), and other (10%). The incidence of post-baseline moderate or severe hypophosphataemia (i.e. serum phosphate [PO4 3- ] level <2.0 mg/dL) varied across the therapeutic areas, with the lowest incidences observed in the HD-CKD (0%), HF (8.1%), and NDD-CKD (12.8%) subgroups. The prevalence of moderate or severe hypophosphataemia among the women's health, other, gastrointestinal, and neurology subgroups was 30.1%, 40.6%, 51.0%, and 55.6%, respectively. In the HF subgroup, one patient (<0.1%) had a serum PO4 3- of <1.0 mg/dL recorded, compared with 4.8% and 4.0% of the subjects in the neurology and gastrointestinal groups, respectively. With the exception of the HD-CKD subgroup, mean serum PO4 3- levels decreased through weeks 2 to 4, and then returned toward baseline and plateaued by week 8. The strongest predictor of hypophosphataemia was preserved kidney function (estimated glomerular filtration rate: >60 mL/min/1.73 m2 vs. <30 mL/min/1.73 m2 ; odds ratio: 12.2). Among patients in the HF subgroup, the incidence of treatment-emergent adverse events potentially related to hypophosphataemia (e.g. cardiac failure, ventricular tachyarrhythmias, fatigue, muscle weakness, bone pain, neurological symptoms, and muscle pain) was lower among FCM-treated patients than among those receiving placebo, and lower among patients with a post-baseline PO4 3- <2 mg/dL vs. those not meeting such criteria.

CONCLUSIONS

The risk of laboratory-assessed hypophosphataemia in HF patients treated with FCM was lower than that seen in patients in other therapeutic areas treated with FCM, and clinical events associated with hypophosphataemia are uncommon with FCM therapy in this population. Appropriate monitoring, particularly soon after administration in the unlikely event of repeated dosing in HF patients, will allow for further refinement of management strategies. [Correction added on 24 February 2023, after first online publication: In the preceding sentence, "…administration, will allow…" has been corrected to "…administration in the unlikely event of repeated dosing in HF patients, will allow…" in this version.].

Hypophosphataemia following ferric derisomaltose and ferric carboxymaltose in patients with iron deficiency anaemia due to inflammatory bowel disease (PHOSPHARE-IBD): a randomised clinical trial

OBJECTIVE

Intravenous iron-a common treatment for anaemia and iron deficiency due to inflammatory bowel disease (IBD)-can cause hypophosphataemia. This trial compared the incidence of hypophosphataemia after treatment with ferric carboxymaltose (FCM) or ferric derisomaltose (FDI).

DESIGN

This randomised, double-blind, clinical trial was conducted at 20 outpatient hospital clinics in Europe (Austria, Denmark, Germany, Sweden, UK). Adults with IBD and iron deficiency anaemia (IDA) were randomised 1:1 to receive FCM or FDI at baseline and at Day 35 using identical haemoglobin- and weight-based dosing regimens. The primary outcome was the incidence of hypophosphataemia (serum phosphate <2.0 mg/dL) at any time from baseline to Day 35 in the safety analysis set (all patients who received ≥1 dose of study drug). Markers of mineral and bone homeostasis, and patient-reported fatigue scores, were measured.

RESULTS

A total of 156 patients were screened; 97 (49 FDI, 48 FCM) were included and treated. Incident hypophosphataemia occurred in 8.3% (4/48) FDI-treated patients and in 51.0% (25/49) FCM-treated patients (adjusted risk difference: -42.8% (95% CI -57.1% to -24.6%) p<0.0001). Both iron formulations corrected IDA. Patient-reported fatigue scores improved in both groups, but more slowly and to a lesser extent with FCM than FDI; slower improvement in fatigue was associated with greater decrease in phosphate concentration.

CONCLUSION

Despite comparably effective treatment of IDA, FCM caused a significantly higher rate of hypophosphataemia than FDI. Further studies are needed to address the longer-term clinical consequences of hypophosphataemia and to investigate mechanisms underpinning the differential effects of FCM and FDI on patient-reported fatigue.

Physiopathology of Phosphate Disorders

Intracellular phosphate is critical for cellular processes such as signaling, nucleic acid synthesis, and membrane function. Extracellular phosphate (Pi) is an important component of the skeleton. Normal levels of serum phosphate are maintained by the coordinated actions of 1,25-dihydroxyvitamin D3, parathyroid hormone and fibroblast growth factor-23, which intersect in the proximal tubule to control the reabsorption of phosphate via the sodium-phosphate cotransporters Npt2a and Npt2c. Furthermore, 1,25-dihydroxyvitamin D3 participates in the regulation of dietary phosphate absorption in the small intestine. Clinical manifestations associated with abnormal serum phosphate levels are common and occur as a result of genetic or acquired conditions affecting phosphate homeostasis. For example, chronic hypophosphatemia leads to osteomalacia in adults and rickets in children. Acute severe hypophosphatemia can affect multiple organs leading to rhabdomyolysis, respiratory dysfunction, and hemolysis. Patients with impaired kidney function, such as those with advanced CKD, have high prevalence of hyperphosphatemia, with approximately two-thirds of patients on chronic hemodialysis in the United States having serum phosphate levels above the recommended goal of 5.5 mg/dL, a cutoff associated with excess risk of cardiovascular complications. Furthermore, patients with advanced kidney disease and hyperphosphatemia (>6.5 mg/dL) have almost one-third excess risk of death than those with phosphate levels between 2.4 and 6.5 mg/dL. Given the complex mechanisms that regulate phosphate levels, the interventions to treat the various diseases associated with hypophosphatemia or hyperphosphatemia rely on the understanding of the underlying pathobiological mechanisms governing each patient condition.

Anemia and Iron Deficiency in Outpatients with Inflammatory Bowel Disease: Ubiquitous Yet Suboptimally Managed

Background: Iron deficiency (ID) and anemia in patients with Inflammatory Bowel Disease (IBD) are associated with a reduced quality of life. We assessed the prevalence of ID and anemia in Dutch outpatients with IBD and compared routine ID(A) management among medical professionals to the European Crohn’s and Colitis Organisation (ECCO) treatment guidelines. Methods: Between January and November 2021, consecutive adult outpatients with IBD were included in this study across 16 Dutch hospitals. Clinical and biochemical data were extracted from medical records. Additionally, medical professionals filled out questionnaires regarding routine ID(A) management. Results: In total, 2197 patients (1271 Crohn’s Disease, 849 Ulcerative Colitis, and 77 IBD-unclassified) were included. Iron parameters were available in 59.3% of cases. The overall prevalence of anemia, ID, and IDA was: 18.0%, 43.4%, and 12.2%, respectively. The prevalence of all three conditions did not differ between IBD subtypes. ID(A) was observed more frequently in patients with biochemically active IBD than in quiescent IBD (ID: 70.8% versus 23.9%; p < 0.001). Contrary to the guidelines, most respondents prescribed standard doses of intravenous or oral iron regardless of biochemical parameters or inflammation. Lastly, 25% of respondents reported not treating non-anemic ID. Conclusions: One in five patients with IBD suffers from anemia that—despite inconsistently measured iron parameters—is primarily caused by ID. Most medical professionals treat IDA with oral iron or standard doses of intravenous iron regardless of biochemical inflammation; however, non-anemic ID is often overlooked. Raising awareness about the management of ID(A) is needed to optimize and personalize routine care.

Serum Phosphate Levels Modify the Impact of FGF23 Levels on Hemoglobin in Chronic Kidney Disease

Anemia is a complication of chronic kidney disease (CKD). Phosphate and fibroblast growth factor-23 (FGF23) have a close relationship, as both are related to the pathogenesis of anemia. However, the possible interplay between them regarding their effect on anemia has not been evaluated. This was a cross-sectional study of 896 participants from the NEFRONA study (273 CKD3, 246 CKD4-5, 282 dialysis and 95 controls). The levels of 25(OH) and 1,25(OH)2 vitamin D, intact FGF23 (iFGF23) and soluble Klotho were measured, together with standard blood biochemistries. Anemia was defined as hemoglobin levels < 13 g/dL in men and <12 g/dL in women. Patients with anemia (407, 45.4%) were younger, mostly men and diabetic; were in advanced CKD stages; had lower calcium, 1,25(OH)2 vitamin D and albumin levels; and had higher ferritin, phosphate, intact PTH, and iFGF23. An inverse correlation was observed between hemoglobin and both iFGF23 and phosphate. The multivariate logistic regression analyses showed that the adjusted risk of anemia was independently associated with higher serum phosphate and LogiFGF23 levels (ORs (95% CIs) of 4.33 (2.11−8.90) and 8.75 (3.17−24.2), respectively (p < 0.001)). A significant interaction between phosphate and iFGF23 (OR of 0.66 (0.53−0.83), p < 0.001) showed that the rise in the adjusted predicted risk of anemia with the increase in iFGF23 was steeper when phosphate levels were low. Phosphate levels acted as modifiers of the effect of iFGF23 concentration on anemia. Thus, the effect of the increase in iFGF23 levels was stronger when phosphate levels were low.

Patient blood management and patient safety

PURPOSE OF REVIEW

The particular fields within patient blood management (PBM) and patient safety reviewed here include novel insights into bleeding therapy, autologous cell salvage, and perioperative anemia therapy.

RECENT FINDING

World Health Organization has published that implementation of PBM is important but has not yet been performed in all hospitals. Two antibodies that mimic the function of FVIII, Emicizumab, and Mim8 have been developed. Tranexamic acid (TXA) has been investigated further in patients with hip surgery and shows reduction of bleeding. Thrombocytopenia in patients undergoing cardiac surgery is a particular concern that has been investigated in another trial. The use of autologous cell salvage was updated in form of a review and meta-analysis. And last but not least, intravenous iron in preoperative anemia therapy can reduce the number of transfusions, but especially iron carboxymaltose can cause hypophosphatemia.

SUMMARY

PBM should be further implemented in more hospitals. Emicizumab and Mim8 are indicated in acquired hemophilia or hemophilia A with inhibitors. TXA was confirmed to reduce bleeding. Autologous cell salvage is state of the art to reduce transfusion requirements in major cardiac and noncardiac surgery. Serum phosphate concentrations should be monitored after administration of intravenous iron compounds.

PTH, FGF-23, Klotho and Vitamin D as regulators of calcium and phosphorus: Genetics, epigenetics and beyond

The actions of several bone-mineral ion regulators, namely PTH, FGF23, Klotho and 1,25(OH)2 vitamin D (1,25(OH)2D), control calcium and phosphate metabolism, and each of these molecules has additional biological effects related to cell signaling, metabolism and ultimately survival. Therefore, these factors are tightly regulated at various levels - genetic, epigenetic, protein secretion and cleavage. We review the main determinants of mineral homeostasis including well-established genetic and post-translational regulators and bring attention to the epigenetic mechanisms that affect the function of PTH, FGF23/Klotho and 1,25(OH)2D. Clinically relevant epigenetic mechanisms include methylation of cytosine at CpG-rich islands, histone deacetylation and micro-RNA interference. For example, sporadic pseudohypoparathyroidism type 1B (PHP1B), a disease characterized by resistance to PTH actions due to blunted intracellular cAMP signaling at the PTH/PTHrP receptor, is associated with abnormal methylation at the GNAS locus, thereby leading to reduced expression of the stimulatory G protein α-subunit (Gsα). Post-translational regulation is critical for the function of FGF-23 and such modifications include glycosylation and phosphorylation, which regulate the cleavage of FGF-23 and hence the proportion of available FGF-23 that is biologically active. While there is extensive data on how 1,25(OH)2D and the vitamin D receptor (VDR) regulate other genes, much more needs to be learned about their regulation. Reduced VDR expression or VDR mutations are the cause of rickets and are thought to contribute to different disorders. Epigenetic changes, such as increased methylation of the VDR resulting in decreased expression are associated with several cancers and infections. Genetic and epigenetic determinants play crucial roles in the function of mineral factors and their disorders lead to different diseases related to bone and beyond.

Advances in understanding of phosphate homeostasis and related disorders

Inorganic phosphate (Pi) in the mammalian body is balanced by its influx and efflux through the intestines, kidneys, bones, and soft tissues, at which several sodium/Pi co-transporters mediate its active transport. Pi homeostasis is achieved through the complex counter-regulatory feedback balance between fibroblast growth factor 23 (FGF23), 1,25-dihydroxyvitamin D (1,25(OH)₂D), and parathyroid hormone. FGF23, which is mainly produced by osteocytes in bone, plays a central role in Pi homeostasis and exerts its effects by binding to the FGF receptor (FGFR) and αKlotho in distant target organs. In the kidneys, the main target, FGF23 promotes the excretion of Pi and suppresses the production of 1,25(OH)₂D. Deficient and excess FGF23 result in hyperphosphatemia and hypophosphatemia, respectively. FGF23-related hypophosphatemic rickets/osteomalacia include tumor-induced osteomalacia and various genetic diseases, such as X-linked hypophosphatemic rickets. Coverage by the national health insurance system in Japan for the measurement of FGF23 and the approval of burosumab, an FGF23-neutralizing antibody, have had a significant impact on the diagnosis and treatment of FGF23-related hypophosphatemic rickets/osteomalacia. Some of the molecules responsible for genetic hypophosphatemic rickets/osteomalacia are highly expressed in osteocytes and function as local regulators of FGF23 production. A number of systemic factors also regulate FGF23 levels. Although the mechanisms responsible for Pi sensing in mammals have not yet been elucidated in detail, recent studies have suggested the involvement of FGFR1. The further clarification of the mechanisms by which osteocytes detect Pi levels and regulate FGF23 production will lead to the development of better strategies to treat hyperphosphatemic and hypophosphatemic conditions.