Ferrous versus ferric oral iron formulations for the treatment of iron deficiency: a clinical overview

Refining Treatment Strategies for Iron Deficient Athletes

Iron deficiency (ID) is a prevailing nutritional concern amongst the athletic population due to the increased iron demands of this group. Athletes' ability to replenish taxed iron stores is challenging due to the low bioavailability of dietary sources, and the interaction between exercise and hepcidin, the primary iron-regulatory hormone. To date, copious research has explored the link between exercise and iron regulation, with a more recent focus on optimising iron treatment applications. Currently, oral iron supplementation is typically the first avenue of iron replacement therapy beyond nutritional intervention, for treatment of ID athletes. However, many athletes encounter associated gastrointestinal side-effects which can deter them from fulfilling a full-term oral iron treatment plan, generally resulting in sub-optimal treatment efficacy. Consequently, various strategies (e.g. dosage, composition, timing) of oral iron supplementation have been investigated with the goal of increasing fractional iron absorption, reducing gastric irritation, and ultimately improving the efficacy of oral iron therapy. This review explores the various treatment strategies pertinent to athletes and concludes a contemporary strategy of oral iron therapy entailing morning supplementation, ideally within the 30 min following morning exercise, and in athletes experiencing gut sensitivity, consumed on alternate days or at lower doses.

Iron Deficiency Anemia in Children Residing in High and Low-Income Countries: Risk Factors, Prevention, Diagnosis and Therapy

Iron deficiency and iron-deficiency anemia (IDA) affects approximately two billion people worldwide, and most of them reside in low- and middle-income countries. In these nations, additional causes of anemia include parasitic infections like malaria, other nutritional deficiencies, chronic diseases, hemoglobinopathies, and lead poisoning. Maternal anemia in resource-poor nations is associated with low birth weight, increased perinatal mortality, and decreased work productivity. Maintaining a normal iron balance in these settings is challenging, as iron-rich foods with good bioavailability are of animal origin and either expensive and/or available in short supply. Apart from infrequent consumption of meat, inadequate vitamin C intake, and diets rich in inhibitors of iron absorption are additional important risk factors for IDA in low-income countries. In-home iron fortification of complementary foods with micronutrient powders has been shown to effectively reduce the risk of iron deficiency and IDA in infants and young children in developing countries but is associated with unfavorable changes in gut flora and induction of intestinal inflammation that may lead to diarrhea and hospitalization. In developed countries, iron deficiency is the only frequent micronutrient deficiency. In the industrialized world, IDA is more common in infants beyond the sixth month of life, in adolescent females with heavy menstrual bleeding, in women of childbearing age and older people. Other special at-risk populations for IDA in developed countries are regular blood donors, endurance athletes, and vegetarians. Several medicinal ferrous or ferric oral iron products exist, and their use is not associated with harmful effects on the overall incidence of infectious illnesses in sideropenic and/or anemic subjects. However, further research is needed to clarify the risks and benefits of supplemental iron for children exposed to parasitic infections in low-income countries, and for children genetically predisposed to iron overload.

Iron and Physical Activity: Bioavailability Enhancers, Properties of Black Pepper (Bioperine®) and Potential Applications

Black pepper (Piper nigrum L.) has been employed in medicine (epilepsy, headaches, and diabetes), where its effects are mainly attributed to a nitrogen alkaloid called piperidine (1-(1-[1,3-benzodioxol-5-yl]-1-oxo-2,4 pentenyl) piperidine). Piperine co-administered with vitamins and minerals has improved its absorption. Therefore, this study aimed to describe the impact of the joint administration of iron (Fe) plus black pepper in physically active healthy individuals. Fe is a micronutrient that aids athletic performance by influencing the physiological functions involved in endurance sports by improving the transport, storage, and utilization of oxygen. Consequently, athletes have risk factors for Fe depletion, Fe deficiency, and eventually, anemia, mainly from mechanical hemolysis, gastrointestinal disturbances, and loss of Fe through excessive sweating. Declines in Fe stores have been reported to negatively alter physical capacities such as aerobic capacity, strength, and skeletal muscle recovery in elite athletes. Thus, there is a need to maintain Fe storage, even if Fe intake meets the recommended daily allowance (RDA), and Fe supplementation may be justified in physically active individuals, in states of Fe deficiency, with or without anemia. Females, in particular, should monitor their Fe hematological profile. The recommended oral Fe supplements are ferrous or ferric salts, sulfate, fumarate, and gluconate. These preparations constitute the first line of treatment; however, the high doses administered have gastrointestinal side effects that reduce tolerance and adherence to treatment. Thus, a strategy to counteract these adverse effects is to improve the bioavailability of Fe. Therefore, piperine may benefit the absorption of Fe through its bioavailability enhancement properties. Three research studies of Fe associated with black pepper have reported improvements in parameters related to the metabolism of Fe, without adverse effects. Although more research is needed, this could represent an advance in oral Fe supplementation for physically active individuals.

Ferric citrate in the management of hyperphosphataemia and iron deficiency anaemia: A meta-analysis in patients with chronic kidney disease

AIMS

Phosphate-lowering effects of ferric citrate were reported in several clinical trials, but mostly in small-scale studies. The aim of this meta-analysis was to investigate the efficacy and safety of ferric citrate in controlling hyperphosphataemia and iron-deficiency anaemia in chronic kidney disease (CKD) patients.

METHODS

PubMed, Embase and Cochrane Library were searched for clinical trials that enrolled CKD patients receiving ferric citrate for hyperphosphataemia. Two investigators performed systematic literature search to identify eligible studies, evaluated risk of bias and extracted relevant data.

RESULTS

Sixteen studies were included in the meta-analysis. Phosphate-lowering effects of ferric citrate were greater compared to no active treatment (standardized mean difference [SMD] = -1.15; P < 0.001) and comparable to other phosphate binders (SMD = 0.03; P = 0.61). Calcium concentrations post ferric citrate treatment did not differ compared to no active treatment (SMD = 0.15; P = 0.21) but were significantly lower compared to other phosphate binders (SMD = -0.14; P = 0.01). These led to significant reductions in calcium-phosphorus product with ferric citrate versus no active control (SMD = -1.02; P < 0.001) but no difference versus active control (SMD = -0.01; P = 0.93). Intact parathyroid hormone showed no substantial between-group difference in both comparison against no active and active controls. Ferric citrate improved iron stores and anaemia parameters, but increased risk of diarrhoea, abdominal pain and discoloured faeces.

CONCLUSION

Ferric citrate was effective in lowering phosphorus and phosphorus-calcium product versus no active treatment and had comparable effects versus other phosphate binders. Calcium levels were significantly lower with ferric citrate than with other phosphate-lowering treatment. Ferric citrate had additive effects on iron repletion and anaemia control and was associated with mostly gastrointestinal side effects.

Advances in Nanoliposomes Production for Ferrous Sulfate Delivery

In this study, a continuous bench scale apparatus based on microfluidic fluid dynamic principles was used in the production of ferrous sulfate-nanoliposomes for pharmaceutical/nutraceutical applications, optimizing their formulation with respect to the products already present on the market. After an evaluation of its fluid dynamic nature, the simil-microfluidic (SMF) apparatus was first used to study the effects of the adopted process parameters on vesicles dimensional features by using ultrasonic energy to enhance liposomes homogenization. Subsequently, iron-nanoliposomes were produced at different weight ratios of ferrous sulfate to the total formulation components (0.06, 0.035, 0.02, and 0.01 w/w) achieving, by using the 0.01 w/w, vesicles of about 80 nm, with an encapsulation efficiency higher than 97%, an optimal short- and long-term stability, and an excellent bioavailability in Caco-2 cell line. Moreover, a comparison realized between the SMF method and two more conventional production techniques showed that by using the SMF setup the process time was drastically reduced, and the process yield increased, achieving a massive nanoliposomes production. Finally, duty-cycle sonication was detected to be a scalable technique for vesicles homogenization.

Evaluating the nutritional content of an insect-fortified food for the child complementary diet in Ghana

BACKGROUND

Due to rising food insecurity, natural resource scarcity, population growth, and the cost of and demand for animal proteins, insects as food have emerged as a relevant topic. This study examines the nutrient content of the palm weevil larva (Rhynchophorus phoenicis), a traditionally consumed edible insect called akokono in Ghana, and assesses its potential as an animal-source, complementary food.

METHODS

Akokono in two "unmixed" forms (raw, roasted) and one "mixed" form (akokono-groundnut paste) were evaluated for their macronutrient, micronutrient, amino acid, and fatty acid profiles.

RESULTS

Nutrient analyses revealed that a 32 g (2 tbsp.) serving of akokono-groundnut paste, compared to recommended daily allowances or adequate intakes (infant 7-12 months; child 1-3 years), is a rich source of protein (99%; 84%), minerals [copper (102%; 66%), magnesium (54%; 51%), zinc (37%; 37%)], B-vitamins [niacin (63%; 42%), riboflavin (26%; 20%), folate (40%; 21%)], Vitamin E (a-tocopherol) (440%; 366%), and linoleic acid (165%; 108%). Feed experiments indicated that substituting palm pith, the typical larval diet, for pito mash, a local beer production by-product, increased the carbohydrate, potassium, calcium, sodium, and zinc content of raw akokono. Akokono-groundnut paste meets (within 10%) or exceeds the levels of essential amino acids specified by the Institute of Medicine criteria for animal-source foods, except for lysine.

CONCLUSIONS

Pairing akokono with other local foods (e.g., potatoes, soybeans) can enhance its lysine content and create a more complete dietary amino acid profile. The promotion of akokono as a complementary food could play an important role in nutrition interventions targeting children in Ghana.

Efficacy and tolerability of oral iron protein succinylate: a systematic review of three decades of research

Objective: Oral supplementation with iron is a standard intervention for treating or preventing iron deficiency with or without anemia. Over the last few decades, various forms of oral iron have been developed to improve treatment tolerability and iron bioavailability. In this review, we gathered research data regarding the use of iron protein succinylate since it was first marketed in the 1980s.Methods: Electronic databases - PubMed and the Cochrane Library - were searched for studies published up to March 2019. Clinical or observational studies reporting data on the tolerability of oral iron protein succinylate were included. Results were statistically described to evaluate and compare the efficacy and safety of iron protein succinylate with the comparators under study.Results: Iron protein succinylate was investigated in 54 studies: 38 randomized clinical trials and 16 observational studies, with a total of 8454 subjects. Of them, 8142 were included in the efficacy analysis: patients were divided into three population subtypes: general (n = 1899), gynecological/obstetric (n = 5283), and pediatric (n = 960). In total, 6450 patients received iron protein succinylate, experiencing a significant change in hemoglobin and ferritin in all populations. The change in all parameters was similar or higher with iron protein succinylate compared to other iron treatments evaluated. Overall, study groups receiving iron protein succinylate reported the lowest rate of adverse events.Conclusions: Although all iron treatments analyzed are effective and safe, our results suggest that iron protein succinylate may be an excellent choice to treat iron deficiency and anemia due to its superior effectiveness and tolerability.

The Effectiveness of Transdermal Iron Patches in Athletes With Suboptimal Iron Status (Part 1)

The authors compared the effectiveness of two modes of daily iron supplementation in athletes with suboptimal iron stores: oral iron (PILL) versus transdermal iron (PATCH). Endurance-trained runners (nine males and 20 females), with serum ferritin concentrations <50 μg/L, supplemented with oral iron or iron patches for 8 weeks, in a parallel group study design. Serum ferritin was measured at baseline and fortnightly intervals. Hemoglobin mass and maximal oxygen consumption (V˙O2max) were measured preintervention and postintervention in PATCH. A linear mixed effects model was used to assess the effectiveness of each mode of supplementation on sFer. A repeated-measures analysis of variance was used to assess hemoglobin mass and V˙O2max outcomes in PATCH. There was a significant time effect (p < .001), sex effect (p = .013), and Time × Group interaction (p = .009) for sFer. At Week 6, PILL had significantly greater sFer compared with PATCH (15.27 μg/L greater in PILL; p = .019). Serum ferritin was 15.53 μg/L greater overall in males compared with females (p = .013). There were no significant differences in hemoglobin mass (p = .727) or V˙O2max (p = .929) preintervention to postintervention in PATCH. Finally, there were six complaints of severe gastrointestinal side effects in PILL and none in PATCH. Therefore, this study concluded that PILL effectively increased sFer in athletes with suboptimal iron stores, whereas PATCH showed no beneficial effects.

The role of iron repletion in adult iron deficiency anemia and other diseases

Iron deficiency anemia (IDA) is the most prevalent and treatable form of anemia worldwide. The clinical management of patients with IDA requires a comprehensive understanding of the many etiologies that can lead to iron deficiency including pregnancy, blood loss, renal disease, heavy menstrual bleeding, inflammatory bowel disease, bariatric surgery, or extremely rare genetic disorders. The treatment landscape for many causes of IDA is currently shifting toward more abundant use of intravenous (IV) iron due to its effectiveness and improved formulations that decrease the likelihood of adverse effects. IV iron has found applications beyond treatment of IDA, and there is accruing data about its efficacy in patients with heart failure, restless leg syndrome, fatigue, and prevention of acute mountain sickness. This review provides a framework to diagnose, manage, and treat patients presenting with IDA and discusses other conditions that benefit from iron supplementation.

Iron Deficiency in Chronic Kidney Disease: Updates on Pathophysiology, Diagnosis, and Treatment

Anemia is a complication that affects a majority of individuals with advanced CKD. Although relative deficiency of erythropoietin production is the major driver of anemia in CKD, iron deficiency stands out among the mechanisms contributing to the impaired erythropoiesis in the setting of reduced kidney function. Iron deficiency plays a significant role in anemia in CKD. This may be due to a true paucity of iron stores (absolute iron deficiency) or a relative (functional) deficiency which prevents the use of available iron stores. Several risk factors contribute to absolute and functional iron deficiency in CKD, including blood losses, impaired iron absorption, and chronic inflammation. The traditional biomarkers used for the diagnosis of iron-deficiency anemia (IDA) in patients with CKD have limitations, leading to persistent challenges in the detection and monitoring of IDA in these patients. Here, we review the pathophysiology and available diagnostic tests for IDA in CKD, we discuss the literature that has informed the current practice guidelines for the treatment of IDA in CKD, and we summarize the available oral and intravenous (IV) iron formulations for the treatment of IDA in CKD. Two important issues are addressed, including the potential risks of a more liberal approach to iron supplementation as well as the potential risks and benefits of IV versus oral iron supplementation in patients with CKD.

Monitoring oral iron therapy in children with iron deficiency anemia: an observational, prospective, multicenter study of AIEOP patients (Associazione Italiana Emato-Oncologia Pediatrica)

Oral ferrous salts are standard treatment for children with iron deficiency anemia (IDA). The objective of our study was to monitor oral iron therapy in children, aged 3 months-12 years, with IDA. We prospectively collected clinical and hematological data of children with IDA, from 15 AIEOP (Associazione Italiana di Ematologia ed. Oncologia Pediatrica) centers. Response was measured by the increase of Hb from baseline. Of the 107 analyzed patients, 18 received ferrous gluconate/sulfate 2 mg/kg (ferrous 2), 7 ferrous gluconate/sulfate 4 mg/kg (ferrous 4), 7 ferric iron salts 2 mg/kg (ferric), 62 bis-glycinate iron 0.45 mg/kg (glycinate), and 13 liposomal iron 0.7-1.4 mg/kg (liposomal). Increase in reticulocytes was evident at 3 days, while Hb increase appeared at 2 weeks. Gain of Hb at 2 and 8 weeks revealed a higher median increase in both ferrous 2 and ferrous 4 groups. Gastro-intestinal side effects were reported in 16% (ferrous 2), 14% (ferrous 4), 6% (glycinate), and 0 (ferric and liposomal) patients. The reticulocyte counts significantly increased after 3 days from the start of oral iron supplementation. Bis-glycinate iron formulation had a good efficacy/safety profile and offers an acceptable alternative to ferrous iron preparations.

Recovery after surgery: do not forget to check iron status before

The perioperative period poses a risk for anemia due to the high prevalence of pre-existing anemia secondary to underlying pathologies in patients who are candidates for surgery, and as a result of the increased blood loss caused by surgery. Pre-operative anemia is an independent risk factor associated with higher risk of blood transfusion and negative surgery outcomes. Anemia and iron deficiency (ID), the main causes of pre-operative anemia, can be easily diagnosed with blood testing and are readily treated before elective surgery. However, pre-surgical screening and treatment of anemia and ID are frequently overlooked. These topics were presented and discussed at the symposium entitled "Recovery after Surgery: Don't Forget to Check Iron Status Before", held at the 11th Annual Meeting of the European Urogynaecological Association (EUGA) in October 2018 in Milan. The objectives of the symposium were to stress the high prevalence and the consequences of pre-operative anemia, illustrated with three clinical cases of women undergoing surgery, and to choose the best option for iron supplementation. In conclusion, it is essential to take time to diagnose and treat iron deficiency anemia (IDA) before surgery. The first-line treatment is oral iron when surgery can be delayed and when there is no intolerance to oral treatment or inefficient uptake, as in the case of iron sequestration or absorption disorders. Among iron preparations, ferrous sulfate in a polymeric complex (FSPC) was found to be one of the treatments of choice to improve hemoglobin iron stores and quality of life in IDA patients.

Magnetic nanoparticles-loaded liposomes as a novel treatment agent for iron deficiency anemia: In vivo study

Iron deficiency anemia (IDA) is a major worldwide public health problem. This is due to its prevalence among infants, children, adolescents, pregnant and reproductive age women. Ferrous sulfate (FeSO₄) is the first line therapy for iron IDA. Unfortunately, it is reported that FeSO₄ suffers from low absorption rate in the body and itself exhibits severe side effects. Herein, iron oxide magnetic nanoparticles-loaded liposomes (LMNPs) are prepared, characterized and evaluated as a treatment regimen for IDA in Wistar rats (as an animal model). Iron oxide magnetic nanoparticles (MNPs) are prepared and loaded into liposomes using the thin film hydration method. The size of the prepared formulations is in the range 10-100 nm, thus it can avoid the reticular endothelial system (RES), and increased their blood circulation time. For in vivo assessment, thirty-five Wistar rats are divided into 5 groups (n = 7): negative control group, positive control group, and three groups treated with different iron formulations (FeSO₄, MNPs and LMNPs). Anemia is induced in the anemic groups by the bleeding method and then treatment started with different iron compounds administrated orally for 13 days. Hematological parameters are followed up during the treatment period. Results indicate that, in the LMNPs group, the hematological parameters turn to normal values and the histopathological structures of the liver, spleen and kidney remain normal. This proves that liposome increases the bioavailability of MNPs. In conclusion, LMNPs demonstrate superiority as a therapeutic regimen for the treatment of IDA among the tested iron formulations.

Novel Oral Iron Therapies for Iron Deficiency Anemia in Chronic Kidney Disease

Iron deficiency anemia (IDA) is a frequent complication of chronic kidney disease (CKD) and is associated with adverse outcomes in these patients. Patients with CKD and IDA remain largely undertreated. Conventional oral iron agents are insufficiently effective due to poor absorption and cause gastrointestinal side effects; thus, novel oral iron preparations are needed. This article covers current treatment guidelines for patients with anemia and CKD and clinical trial data for iron-repletion agents currently in use, as well as for novel oral iron therapies in development. Ferric citrate, a novel oral iron-repletion agent approved for patients with non-dialysis-dependent CKD and IDA, demonstrated improvements in hemoglobin levels and iron parameters, with good tolerability in patients with non-dialysis-dependent CKD. When used as a phosphate binder, ferric citrate also improves hemoglobin and iron parameters in dialysis-dependent CKD, but additional trials are needed to evaluate its efficacy as an iron-repletion agent in this setting. Other novel oral iron preparations in development for IDA in patients with CKD include ferric maltol, which is approved in Europe and the United States for IDA in adult patients, and sucrosomial iron, which has been evaluated in IDA associated with CKD and several other clinical settings.

Effects of 6-months of oral ferrous and ferric supplement therapy in patients who were hospitalized for decompensated chronic heart failure

Objective

Anemia is common in patients with chronic heart failure (CHF). This study aimed to examine the frequency of iron deficiency anemia in patients with CHF. We investigated the effects of oral ferrous or ferric supplementation on prognosis of CHF and quality of life.

Methods

A total of 201 patients with chronic decompensated heart failure were enrolled in a 6-month prospective study. Patients were randomly assigned to two groups. Patients in group I (n = 100) received ferrous fumarate and those in group II (n = 101) received ferric hydroxide polymaltose complex. Quality of life was measured by the 6-minute walking test (6MWT).

Results

A total of 49% of the patients had iron-dependent anemia in group I and 53.3% were anemic in group II. In group I, the number of anemic patients was significantly lower at 6 months after admission compared with at initial admission (49% versus 45%). Significant improvements were observed in hemoglobin values, the 6MWT distance, and New York Heart Association class after 6 months in both groups.

Conclusions

Iron deficiency is a significant comorbidity in CHF, even without anemia. Iron should be replaced orally or intravenously because it significantly improves the quality of life of patients.

Preventing complications by persistence with iron replacement therapy: a comprehensive literature review

OBJECTIVE

Iron deficiency and particularly iron deficiency anemia (IDA) can lead to negative health consequences. This review describes the importance of adherence and persistence (adhering to treatment for the recommended duration) with iron replacement therapy in the prevention of complications, particularly regarding its recommended dosing schedule.

METHODS

Comprehensive literature searches were performed of Medline and the Cochrane library from 2000 to 2018. Keywords included iron deficiency or IDA, compliance or adherence, persistence, health beliefs, risk factor, complications, dosing cycles, oral iron replacement therapy and recommendations for duration, ferrous compounds, iron supplementation, dietary iron, and delayed-action/slow-release preparations.

RESULTS

Identified articles focused on IDA as a risk factor (particularly for worsened comorbidities or surgical outcomes), guidelines, adherence and persistence, and differences between iron formulations. Current guidelines and expert opinion continue to support oral iron supplementation as first-line therapy. While it is recommended to take iron therapy for 2 months to normalize hemoglobin, then 2-3 months to build up iron stores, many patients face difficulties in adhering to and persisting with the full iron treatment regimen. Patient education and understanding, social support, simple dosing, perceived efficacy including reduced symptoms and tolerability were factors noted to promote medication adherence and persistence. Adherence to iron therapies appears to be facilitated by using ferrous sulfate due to its optimal absorption, and particularly extended-release forms due to their improved tolerability for iron deficiency.

CONCLUSIONS

Proper adherence and persistence with iron supplementation may prevent or reduce the risk of complications of iron deficiency and IDA.

Mechanism of Action and Clinical Attributes of Auryxia® (Ferric Citrate)

Chronic kidney disease (CKD) is a major cause of morbidity and premature mortality and represents a significant global public health issue. Underlying this burden are the many complications of CKD, including mineral and bone disorders, anemia, and accelerated cardiovascular disease. Hyperphosphatemia and elevated levels of fibroblast growth factor 23 (FGF23) have been identified as key independent risk factors for the adverse cardiovascular outcomes that frequently occur in patients with CKD. Auryxia® (ferric citrate; Keryx Biopharmaceuticals, Inc., Boston, MA, USA) is an iron-based compound with distinctive chemical characteristics and a mechanism of action that render it dually effective as a therapy in patients with CKD; it has been approved as a phosphate binder for the control of serum phosphate levels in adult CKD patients treated with dialysis and as an iron replacement product for the treatment of iron deficiency anemia in adult CKD patients not treated with dialysis. This review focuses on Auryxia, its mechanism of action, and the clinical attributes that differentiate it from other, non-pharmaceutical-grade, commercially available forms of ferric citrate and from other commonly used phosphate binder and iron supplement therapies for patients with CKD. Consistent with the chemistry and mechanism of action of Auryxia, multiple clinical studies have demonstrated its efficacy in both lowering serum phosphate levels and improving iron parameters in patients with CKD. Levels of FGF23 decrease significantly with Auryxia treatment, but the effects associated with the cardiovascular system remain to be evaluated in longer-term studies.

Iron considerations for the athlete: a narrative review

Iron plays a significant role in the body, and is specifically important to athletes, since it is a dominant feature in processes such as oxygen transport and energy metabolism. Despite its importance, athlete populations, especially females and endurance athletes, are commonly diagnosed with iron deficiency, suggesting an association between sport performance and iron regulation. Although iron deficiency is most common in female athletes (~ 15-35% athlete cohorts deficient), approximately 5-11% of male athlete cohorts also present with this issue. Furthermore, interest has grown in the mechanisms that influence iron absorption in athletes over the last decade, with the link between iron regulation and exercise becoming a research focus. Specifically, exercise-induced increases in the master iron regulatory hormone, hepcidin, has been highlighted as a contributing factor towards altered iron metabolism in athletes. To date, a plethora of research has been conducted, including investigation into the impact that sex hormones, diet (e.g. macronutrient manipulation), training and environmental stress (e.g. hypoxia due to altitude training) have on an athlete's iron status, with numerous recommendations proposed for consideration. This review summarises the current state of research with respect to the aforementioned factors, drawing conclusions and recommendations for future work.

DMT1 and iron transport

Many past and recent advances in the field of iron metabolism have relied upon the discovery of divalent metal transporter 1, DMT1 in 1997. DMT1 is the major iron transporter and contributes non-heme iron uptake in most types of cell. Each DMT1 isoform exhibits different expression patterns in cell-type specificity and distinct subcellular distribution, which enables cells to uptake both transferrin-bound and non-transferrin-bound irons efficiently. DMT1 expression is regulated by iron through the translational and degradation pathways to ensure iron homeostasis. It is considered that mammalian iron transporters including DMT1 cannot transport ferric iron but ferrous iron. Being reduced to ferrous state is likely to damage cells and tissues through the production of reactive oxygen species. Recently, iron chaperones have been identified, which can provide an answer to how ferrous iron is transported safely in cytosol. We summarize DMT1 expression depending on the types of cell or tissue and the function and mechanism of one of the iron chaperones, PCBP2.

Role of intravenous iron in the treatment of anemia in patients with gastrointestinal tract tumors undergoing chemotherapy: a single-center, observational study

Purpose

The prevalence of anemia ranges between 30% and 90% in cancer patients, affecting the health status, quality of life, and treatment outcome. Therefore, a proper diagnosis and management of anemia is crucial in these patients. Iron deficiency is diagnosed in~32%–60% of the cases. In this observational study, we evaluated the efficacy and safety of intravenous iron (ferric carboxymaltose [FCM], Ferinject^®) in the treatment of iron-deficiency anemia in patients with gastrointestinal tumors undergoing palliative or adjuvant chemotherapy.

Patients and methods

Thirty patients with gastrointestinal tumors undergoing chemotherapy diagnosed with iron-deficiency anemia were included in the study and received at least one FCM administration. The need for iron replacement therapy was evaluated by the assessment of hemoglobin and iron status parameters, and patients could be treated with FCM during 12–14 weeks. Paired t-test approach was used to evaluate the mean differences between the baseline and the end of the study. A p-value of <0.05 was considered statistically significant.

Results

Data showed that there was a statistically significant increase in the mean of hemoglobin (10.3 vs 11.2 g/dL), ferritin (230.3 vs 877.0 ng/mL), transferrin saturation (13.0% vs 19.7%), and serum iron (42.3 vs 59.6 mg/mL) from the baseline to the end of the study in cancer patients. Most of the patients (n=25) were only administered one dose of FCM. There was one FCM-related adverse event during the study.

Conclusion

FCM was well tolerated and had a positive impact in the treatment of iron-deficiency anemia in patients with gastrointestinal tract tumors undergoing chemotherapy.

The evaluation of alternative method of ferrous ions assessment in pharmaceutical preparations

ABSTRACT

The atomic absorption spectrometry (AAS) method is one of the most accessible procedures for ferrous ions testing in various compositions including pharmaceutical preparations. The aim of the study was to develop and partially validate analytical method which could be an excellent alternative to the routine procedure performed within dissolution studies. Electric conductivity is simple, fast, and hassle-free method. The samples during dissolution process were measured using conductivity probe in entire dissolution assessment protocol. The conductivity results were compared to data obtained from AAS. The dissolution studies were performed according to modified pharmacopoeial standards, in 900 cm3 of purified water as an acceptor medium, at 37 °C, until the achievement of an equilibrium state for every tested composition. Validity study of the developed method confirmed acceptable linearity of obtained calibration plots (r2 > 0.9553). Linearity at 100% level was found to be 100.59, 97.49, and 94.82, respectively, for drug compositions A, B, and C. Precision results were 100.45, 95.97, and 95.73, respectively, for A, B, and C, with RSD below 2% between all samples in all above mentioned formulations. The drug composition D hindered the proper validation of the method due to the high variability between samples. The method has acceptable performance features for evaluation of three of four solid drug composition containing ferrous ions.

GRAPHICAL ABSTRACT

Rational Management of Iron-Deficiency Anaemia in Inflammatory Bowel Disease

Anaemia is the most frequent, though often neglected, comorbidity of inflammatory bowel disease (IBD). Here we want to briefly present (1) the burden of anaemia in IBD, (2) its pathophysiology, which mostly arises from bleeding-associated iron deficiency, followed by (3) diagnostic evaluation of anaemia, (4) a balanced overview of the different modes of iron replacement therapy, (5) evidence for their therapeutic efficacy and subsequently, (6) an updated recommendation for the practical management of anaemia in IBD. Following the introduction of various intravenous iron preparations over the last decade, questions persist about when to use these preparations as opposed to traditional and other novel oral iron therapeutic agents. At present, oral iron therapy is generally preferred for patients with quiescent IBD and mild iron-deficiency anaemia. However, in patients with flaring IBD that hampers intestinal iron absorption and in those with inadequate responses to or side effects with oral preparations, intravenous iron supplementation is the therapy of choice, although information on the efficacy of intravenous iron in patients with active IBD and anaemia is scare. Importantly, anaemia in IBD is often multifactorial and a careful diagnostic workup is mandatory for optimized treatment. Nevertheless, limited information is available on optimal therapeutic start and end points for treatment of anaemia. Of note, neither oral nor intravenous therapies seem to exacerbate the clinical course of IBD. However, additional prospective studies are still warranted to determine the optimal therapy in complex conditions such as IBD.

Considerations for Secondary Prevention of Nutritional Deficiencies in High-Risk Groups in High-Income Countries

Surveys in high-income countries show that inadequacies and deficiencies can be common for some nutrients, particularly in vulnerable subgroups of the population. Inadequate intakes, high requirements for rapid growth and development, or age- or disease-related impairments in nutrient intake, digestion, absorption, or increased nutrient losses can lead to micronutrient deficiencies. The consequent subclinical conditions are difficult to recognize if not screened for and often go unnoticed. Nutrient deficiencies can be persistent despite primary nutrition interventions that are aimed at improving dietary intakes. Secondary prevention that targets groups at high risk of inadequacy or deficiency, such as in the primary care setting, can be a useful complementary approach to address persistent nutritional gaps. However, this strategy is often underestimated and overlooked as potentially cost-effective means to prevent future health care costs and to improve the health and quality of life of individuals. In this paper, the authors discuss key appraisal criteria to consider when evaluating the benefits and disadvantages of a secondary prevention of nutrient deficiencies through screening.

Modern iron replacement therapy: clinical and pathophysiological insights

Iron deficiency, with or without anemia, is extremely frequent worldwide, representing a major public health problem. Iron replacement therapy dates back to the seventeenth century, and has progressed relatively slowly until recently. Both oral and intravenous traditional iron formulations are known to be far from ideal, mainly because of tolerability and safety issues, respectively. At the beginning of this century, the discovery of hepcidin/ferroportin axis has represented a turning point in the knowledge of the pathophysiology of iron metabolism disorders, ushering a new era. In the meantime, advances in the pharmaceutical technologies are producing newer iron formulations aimed at minimizing the problems inherent with traditional approaches. The pharmacokinetic of oral and parenteral iron is substantially different, and diversities have become even clearer in light of the hepcidin master role in regulating systemic iron homeostasis. Here we review how iron therapy is changing because of such important advances in both pathophysiology and pharmacology.

Management of inflammatory bowel disease-related anemia and iron deficiency with specific reference to the role of intravenous iron in current practice

Anemia is a common extraintestinal manifestation in patients with inflammatory bowel disease, impacting disease prognosis, morbidity, hospitalization rates and time lost from work. While iron deficiency anemia and anemia of chronic inflammation predominate, combinations of hematimetric and biochemical markers facilitate the diagnosis and targeted therapy of other etiologies according to their underlying pathophysiological causes. Intravenous iron replacement is currently recommended in IBD patients with moderate to severe anemia or intolerance to oral iron. Areas covered: This review examines the impact, pathophysiology and diagnostics of iron deficiency and anemia, compares the characteristics and safety profiles of available oral and intravenous iron preparations, and highlights issues which require consideration in decision making for therapy administration and monitoring. Expert opinion: Modern intravenous iron formulations have been shown to be safe and effective in IBD patients, allowing rapid anemia correction and repletion of iron stores. While traditional oral iron preparations are associated with increased inflammation, negative effects on the microbiome, and poor tolerance and compliance, first clinical trial data indicate that newer oral compounds such as ferric maltol and sucrosomial iron offer improved tolerability and may thus offer a viable alternative for the future.

Iron deficiency anemia in pregnant women

Screening for iron deficiency anemia (IDA) in all pregnant women is recommended. IDA is a prevalent cause of nutritional deficiency anemia, and oral iron is the first line of treatment. Other treatments include parenteral iron or blood transfusion(s). Untreated IDA in pregnancy can result in complications for the mother and fetus.

Insights into the diagnosis and management of iron deficiency in inflammatory bowel disease

INTRODUCTION

Iron deficiency is a frequent comorbidity of chronic diseases such as inflammatory bowel disease that can severely impact the health and quality of life of affected individuals. It can exist as a silent condition and manifest in non-specific symptoms even in the absence of anemia. Even though iron deficiency anemia is the most common complication and extra-intestinal manifestation of inflammatory bowel disease, the majority of inflammatory bowel disease patients who are diagnosed with iron deficiency anemia are not treated. Areas covered: In this review, we discuss iron deficiency and iron deficiency anemia in patients with inflammatory bowel disease, and review diagnostic and therapeutic options. Expert commentary: We invite international gastroenterological societies and associations to refine the practice guidelines and include iron deficiency as a potential morbidity associated with IBD in analogy to arthritis, uveitis or any other extra intestinal manifestations. There should a more unanimous agreement among different societies on the specific diagnostic cutoff values for C-reactive protein levels, serum ferritin, and transferrin saturation in order to differentiate iron deficiency anemia from anemia of chronic disease.

Iron Therapy in Patients with Heart Failure and Iron Deficiency: Review of Iron Preparations for Practitioners

In patients with heart failure (HF), iron deficiency (ID) correlates with decreased exercise capacity and poor health-related quality of life, and predicts worse outcomes. Both absolute (depleted iron stores) and functional (where iron is unavailable for dedicated tissues) ID can be easily evaluated in patients with HF using standard laboratory tests (assessment of serum ferritin and transferrin saturation). Intravenous iron therapy in iron-deficient patients with HF and reduced ejection fraction has been shown to alleviate HF symptoms and improve exercise capacity and quality of life. In this paper, we provide information on how to diagnose ID in HF. Further we discuss pros and cons of different iron preparations and discuss the results of major trials implementing iron supplementation in HF patients, in order to provide practical guidance for clinicians on how to manage ID in patients with HF.

Effect of Ayurveda Medications (Kasīsa Bhasma and Dhātrī Avaleha) on Iron Deficiency Anaemia: A Randomized Controlled Study

Background:

This paper explores the role that Ayurveda can play in the management of Iron Deficiency Anaemia, a major nutritional deficiency disorder affecting people across the globe.

Methodology:

Forty (40) patients suffering from Iron deficiency anaemia as per WHO guidelines, between the age group of 20 to 60 yrs of either sex participated in the study. Study was a randomized, controlled, open label clinical study. Patients were randomly divided into two groups: Group D (n = 20) received Dhārī avaleha 10 g twice a day after food. Group K (n = 20) received capsules Kasīsa bhasma 125 mg thrice a day. Both interventions were administered for 30 days and the subjects were followed up for next 30 days with placebo capsules to assess the sustainability of the effects. Assessments were done at baseline, 30^th and 60^th days. Primary outcome measure was hemoglobin estimation (Hb) and secondary outcome measures were the other hematological parameters such as Red blood cell (RBC) indices, total RBC count, Packed Cell volume (PCV) and Peripheral Blood smear study.

Results:

Both interventions produced significant improvements (P < 0.001). Kasīsa bhasma was better compared to dhātrī avaleha in terms of primary (P < 0.0001) and secondary outcomes. Comparison of outcomes from base line – 30^th day, base line – 60^th day and 30^th – 60^th day showed significant (P < 0.0001) improvement in both the groups in parameters such as haemoglobin, MCV and MCH. Hence improvements sustained during placebo intervened sustainability period also.

Conclusions:

Study effectively shows that Kasīsa bhasma is better then Dhātrī avaleha. Improvements by both interventions were sustained even during the sustainability period.

Silkworm feces extract improves iron deficiency anemia via suppressing hepcidin expression and promoting iron-regulatory proteins expression

In this study, we aimed to explore the preventive efficacy of SFE toward iron deficiency anemia in rats and clarify the underlying mechanisms. Findings suggest that SFE may be an efficient oral iron supplement to ameliorate iron deficiency anemia.

Using Hematology Data from Malaria Vaccine Research Trials in Humans and Rhesus Macaques (Macaca mulatta) To Guide Volume Limits for Blood Withdrawal

Guidelines on safe volume limits for blood collection from research participants in both humans and laboratory animals vary widely between institutions. The main adverse event that may be encountered in large blood volume withdrawal is iron-deficiency anemia. Monitoring various parameters in a standard blood panel may help to prevent this outcome. To this end, we analyzed the Hgb and MCV values from 43 humans and 46 macaques in malaria vaccine research trials. Although the percentage of blood volume removed was greater for macaques than humans, macaques demonstrated an overall increase of MCV over time, indicating the ability to respond appropriately to frequent volume withdrawals. In contrast, humans showed a consistent declining trend in MCV. These declines in human MCV and Hgb were significant from the beginning to end of the study despite withdrawals that were smaller than recommended volume limits. Limiting the volume withdrawn to no more than 12.5% seemed to be sufficient for macaques, and at 14% or more individual animals tended to fail to respond appropriately to large-volume blood loss, as demonstrated by a decrease in MCV. The overall positive erythropoietic response seen in macaques was likely due to the controlled, iron-fortified diet they received. The lack of erythropoietic response in the human subjects may warrant iron supplementation or reconsideration of current blood volume withdrawal guidelines.

Preparation and Bioavailability Analysis of Ferrous Bis Alanine Chelate as a New Micronutrient for Treatment of Iron Deficiency Anemia

Purpose: One of the most nutritional disorders around the world is iron deficiency. A novel iron compound was synthesized by chelating ferrous ions with alanine for prevention and treatment of iron deficiency anemia. Methods: The newly synthesized compound was characterized both qualitatively and quantitatively by Fourier Transform Infrared (FT-IR) spectroscopy. The bioavailability of newly synthesized iron micronutrient was evaluated in four groups of Wistar rats. The group I was a negative control group and the other three groups received three different iron formulations. After 14 days, the blood samples were taken and analyzed accordingly. Results: Calculations showed that more than 91.8% of iron was incorporated in the chelate formulation. In vivo studies showed that serum iron, total iron binding capacity and hemoglobin concentrations were significantly increased in group IV, which received ferrous bis alanine chelate compared with the negative control group (p<0.05) and also group II, which received ferrous sulfate.7H2O (p<0.05). It indicates that the new formulation considerably improves the blood iron status compared with the conventional iron compounds. There were no significant differences (p<0.05) in the serum iron between group IV and group III, which received ferrous bis glycine. Conclusion: The results showed better bioavailability of ferrous bis alanine as a new micronutrient for treatment of iron deficiency anemia in comparison with ferrous sulfate. Ferrous bis alanine could be considered as a suitable supplement for prevention and treatment of iron deficiency anemia.

A novel oral iron-complex formulation: Encapsulation of hemin in polymeric micelles and its in vitro absorption

Anemia resulting from iron deficiency is one of the most prevalent diseases in the world. As iron has important roles in several biological processes such as oxygen transport, DNA synthesis and cell growth, there is a high need for iron therapies that result in high iron bioavailability with minimal toxic effects to treat patients suffering from anemia. This study aims to develop a novel oral iron-complex formulation based on hemin-loaded polymeric micelles composed of the biodegradable and thermosensitive polymer methoxy-poly(ethylene glycol)-b-poly[N-(2-hydroxypropyl)methacrylamide-dilactate], abbreviated as mPEG-b-p(HPMAm-Lac₂). Hemin-loaded micelles were prepared by addition of hemin dissolved in DMSO:DMF (1:9, one volume) to an aqueous polymer solution (nine volumes) of mPEG-b-p(HPMAm-Lac₂) followed by rapidly heating the mixture at 50°C to form hemin-loaded micelles that remain intact at room and physiological temperature. The highest loading capacity for hemin in mPEG-b-p(HPMAm-Lac₂) micelles was 3.9%. The average particle diameter of the hemin-micelles ranged from 75 to 140nm, depending on the concentration of hemin solution that was used to prepare the micelles. The hemin-loaded micelles were stable at pH 2 for at least 3 h which covers the residence time of the formulation in the stomach after oral administration and up to 17 h at pH 7.4 which is sufficient time for uptake of the micelles by the enterocytes. Importantly, incubation of Caco-2 cells with hemin-micelles for 24 h at 37°C resulted in ferritin levels of 2500ng/mg protein which is about 10-fold higher than levels observed in cells incubated with iron sulfate under the same conditions. The hemin formulation also demonstrated superior cell viability compared to iron sulfate with and without ascorbic acid. The study presented here demonstrates the development of a promising novel iron complex for oral delivery.

Iron replacement therapy: do we need new guidelines?

PURPOSE OF REVIEW

Approximately, one-third of the world's population suffers from anemia, and at least half of these cases are because of iron deficiency. With the introduction of new intravenous iron preparations over the last decade, uncertainty has arisen when these compounds should be administered and under which circumstances oral therapy is still an appropriate and effective treatment.

RECENT FINDINGS

Numerous guidelines are available, but none go into detail about therapeutic start and end points or how iron-deficiency anemia should be best treated depending on the underlying cause of iron deficiency or in regard to concomitant underlying or additional diseases.

SUMMARY

The study points to major issues to be considered in revisions of future guidelines for the true optimal iron replacement therapy, including how to assess the need for treatment, when to start and when to stop treatment, when to follow-up for relapse, which dosage and type of therapy should be recommended or not recommended, and if some patients should not be treated.

The role of ferric carboxymaltose in the treatment of iron deficiency anemia in patients with gastrointestinal disease

Iron deficiency anemia (IDA) is the most common form of nutritional anemia worldwide. Iron plays a pivotal role in vital functioning of almost every organ system. IDA affects both physical and psychological functioning of humans. Oral iron is considered as first-line therapy for the treatment of IDA due to low cost, good safety profile and ease of administration. However, the absorption of oral iron is affected by several factors and incidence of gastrointestinal side effects can lead to lack of adherence to therapy as well as poor efficacy. This has led to the emergence of intravenous iron therapy which is clearly superior to oral iron with higher increment of hemoglobin levels and rapid replenishment of iron stores. Ferric carboxymaltose (FCM) is a novel non-dextran intravenous iron form which has been approved for use in patients with iron deficiency who have had inadequate response to oral iron therapy, intolerance to oral iron, or nondialysis-dependent chronic kidney disease. The safety and efficacy of using FCM for the treatment of IDA has been demonstrated in several clinical trials. One dose can provide a large amount of iron and has a very short infusion time. It should be considered as first-line therapy in patients with active inflammation like inflammatory bowel disease when gastrointestinal absorption of oral iron may be compromised. It should also be given to patients who have inadequate response to oral iron therapy. It has been shown to be noninferior to other intravenous iron formulations with a good safety profile and produced fewer anaphylactic reactions.

Ferric maltol (ST10): a novel oral iron supplement for the treatment of iron deficiency anemia in inflammatory bowel disease

INTRODUCTION

Iron deficiency anemia affects up to three quarters of patients with inflammatory bowel disease (IBD). It can significantly impact the quality of life and the ability to work by impairing physical, emotional, and cognitive functioning. The etiology of iron deficiency anemia is multifactorial and oral or intravenous iron replacement is necessary. However, oral iron supplements are often discontinued prematurely due to poor tolerability or insufficient efficacy. Moreover, intravenous supplementation is inconvenient, associated with potentially serious safety risks, and a burden on healthcare resources.

AREAS COVERED

Ferric maltol is a novel ferric iron compound with potential use as an oral therapy for iron deficiency anemia. This overview explains how the molecule's design impacts clinical outcomes and summarizes available clinical data (ranging from early comparisons with ferrous sulfate to randomized, placebo-controlled, Phase III data in patients with IBD known to be intolerant of oral ferrous products).

EXPERT OPINION

Ferric maltol offers the ability to treat iron deficiency anemia in mild-to-moderate IBD without resorting to intravenous therapy, even in those who are intolerant of oral ferrous products. This clinical benefit has the potential to change treatment pathways and increase choice, not only in IBD but also perhaps in many areas beyond gastroenterology.

Iron deficiency anemia in pregnancy

Anemia is the most frequent derailment of physiology in the world throughout the life of a woman. It is a serious condition in countries that are industrialized and in countries with poor resources. The main purpose of this manuscript is to give the right concern of anemia in pregnancy. The most common causes of anemia are poor nutrition, iron deficiencies, micronutrients deficiencies including folic acid, vitamin A and vitamin B12, diseases like malaria, hookworm infestation and schistosomiasis, HIV infection and genetically inherited hemoglobinopathies such as thalassemia. Depending on the severity and duration of anemia and the stage of gestation, there could be different adverse effects including low birth weight and preterm delivery. Treatment of mild anemia prevents more severe forms of anemia, strictly associated with increased risk of fetal-maternal mortality and morbidity.

Management of Iron-Deficiency Anemia in Inflammatory Bowel Disease: A Systematic Review

Anemia is the most frequent complication of inflammatory bowel disease (IBD), but anemia, mostly due to iron deficiency, has long been neglected in these patients. The aim was to briefly present the pathophysiology, followed by a balanced overview of the different forms of iron replacement available, and subsequently, to perform a systematic review of studies performed in the last decade on the treatment of iron-deficiency anemia in IBD. Given that intravenous therapies have been introduced in the last decade, a systematic review performed in PubMed, EMBASE, the Cochrane Library, and the websites of WHO, FDA, and EMA covered prospective trials investigating the management of iron-deficiency anemia in IBD published since 2004. A total of 632 articles were reviewed, and 13 articles (2906 patients) with unique content were included. In general, oral supplementation in iron-deficiency anemia should be administered with a target to restore/replenish the iron stores and the hemoglobin level in a suitable way. However, in patients with IBD flares and inadequate responses to or side effects with oral preparations, intravenous iron supplementation is the therapy of choice. Neither oral nor intravenous therapy seems to exacerbate the clinical course of IBD, and intravenous iron therapy can be administered even in active disease stages and concomitantly with biologics. In conclusion, because many physicians are in doubt as to how to manage anemia and iron deficiency in IBD, there is a clear need for the implementation of evidence-based recommendations on this matter. Based on the data presented, oral iron therapy should be preferred for patients with quiescent disease stages and trivial iron deficiency anemia unless such patients are intolerant or have an inadequate response, whereas intravenous iron supplementation may be of advantage in patients with aggravated anemia or flares of IBD because inflammation hampers intestinal absorption of iron.

Population pharmacokinetic meta-analysis to bridge ferumoxytol plasma pharmacokinetics across populations

BACKGROUND

Ferumoxytol is approved for the treatment of iron-deficiency anaemia (IDA) in adult patients with chronic kidney disease (CKD). Ferumoxytol has recently been investigated for use in all-cause IDA. This analysis was employed to bridge ferumoxytol pharmacokinetics (PK) across populations of healthy subjects and patients with CKD on haemodialysis, and to then make informed inferences regarding the PK behaviour of ferumoxytol in the all-cause IDA population.

METHODS

The data analysis was performed using NONMEM. Selected parameters were included for covariate testing. Investigations to determine if changes in volume of distribution during haemodialysis improved the model fit were also conducted. The final model was used to simulate PK in healthy volunteers (HVs) and CKD patients with and without haemodialysis.

RESULTS

The final model was a two-compartment model with non-linear elimination. During haemodialysis, the central volume V1 was estimated to be reduced by 0.198 L/h. A positive relationship was identified between initial V1 and observed weight loss during haemodialysis. V1 increased by 0.614 % per kilogram of body weight, and females had an 18.3 % lower V1 than males. Differences between simulated profiles for different populations were marginal: maximum concentration (Cmax) of 209 vs. 204 ng/mL and area under the curve from time zero to infinity (AUCinf) of 5,980 vs. 5,920 ng·h/mL in HVs and CKD non-haemodialysis patients, respectively, for a single dose of 510 mg.

CONCLUSIONS

The results indicate that ferumoxytol PK are comparable between HVs and CKD patients. Furthermore, the results are representative of the PK in other populations and can be used to bridge to subjects with general IDA.

Ferrous sulfate supplementation causes significant gastrointestinal side-effects in adults: a systematic review and meta-analysis

Background

The tolerability of oral iron supplementation for the treatment of iron deficiency anemia is disputed.

Objective

Our aim was to quantify the odds of GI side-effects in adults related to current gold standard oral iron therapy, namely ferrous sulfate.

Methods

Systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating GI side-effects that included ferrous sulfate and a comparator that was either placebo or intravenous (IV) iron. Random effects meta-analysis modelling was undertaken and study heterogeneity was summarised using I² statistics.

Results

Forty three trials comprising 6831 adult participants were included. Twenty trials (n = 3168) had a placebo arm and twenty three trials (n = 3663) had an active comparator arm of IV iron. Ferrous sulfate supplementation significantly increased risk of GI side-effects versus placebo with an odds ratio (OR) of 2.32 [95% CI 1.74–3.08, p<0.0001, I² = 53.6%] and versus IV iron with an OR of 3.05 [95% CI 2.07-4.48, p<0.0001, I² = 41.6%]. Subgroup analysis in IBD patients showed a similar effect versus IV iron (OR = 3.14, 95% CI 1.34-7.36, p = 0.008, I² = 0%). Likewise, subgroup analysis of pooled data from 7 RCTs in pregnant women (n = 1028) showed a statistically significant increased risk of GI side-effects for ferrous sulfate although there was marked heterogeneity in the data (OR = 3.33, 95% CI 1.19-9.28, p = 0.02, I² = 66.1%). Meta-regression did not provide significant evidence of an association between the study OR and the iron dose.

Conclusions

Our meta-analysis confirms that ferrous sulfate is associated with a significant increase in gastrointestinal-specific side-effects but does not find a relationship with dose.