Soluble transferrin receptor in Aboriginal children with a high prevalence of iron deficiency and infection

INFERR-Iron infusion in haemodialysis study: INtravenous iron polymaltose for First Nations Australian patients with high FERRitin levels on haemodialysis-a protocol for a prospective open-label blinded endpoint randomised controlled trial

BACKGROUND

The effectiveness of erythropoiesis-stimulating agents, which are the main stay of managing anaemia of chronic kidney disease (CKD), is largely dependent on adequate body iron stores. The iron stores are determined by the levels of serum ferritin concentration and transferrin saturation. These two surrogate markers of iron stores are used to guide iron replacement therapy. Most Aboriginal and/or Torres Islander Australians of the Northern Territory (herein respectfully referred to as First Nations Australians) with end-stage kidney disease have ferritin levels higher than current guideline recommendations for iron therapy. There is no clear evidence to guide safe and effective treatment with iron in these patients. We aim to assess the impact of intravenous iron treatment on all-cause death and hospitalisation with a principal diagnosis of all-cause infection in First Nations patients on haemodialysis with anaemia, high ferritin levels and low transferrin saturation METHODS: In a prospective open-label blinded endpoint randomised controlled trial, a total of 576 participants on maintenance haemodialysis with high ferritin (> 700 μg/L and ≤ 2000 μg/L) and low transferrin saturation (< 40%) from all the 7 renal units across the Northern Territory of Australia will be randomised 1:1 to receive intravenous iron polymaltose 400 mg once monthly (200 mg during 2 consecutive haemodialysis sessions) (Arm A) or no IV iron treatment (standard treatment) (Arm B). Rescue therapy will be administered when the ferritin levels fall below 700 μg/L or when clinically indicated. The primary outcome will be the differences between the two study arms in the risk of hospitalisation with all-cause infection or death. An economic analysis and several secondary and tertiary outcomes analyses will also be performed.

DISCUSSION

The INFERR clinical trial will address significant uncertainty on the safety and efficacy of iron therapy in First Nations Australians with CKD with hyperferritinaemia and evidence of iron deficiency. This will hopefully lead to the development of evidence-based guidelines. It will also provide the opportunity to explore the causes of hyperferritinaemia in First Nations Australians from the Northern Territory.

TRIAL REGISTRATION

This trial is registered with The Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12620000705987 . Registered 29 June 2020.

Narrative Review of Hyperferritinemia, Iron Deficiency, and the Challenges of Managing Anemia in Aboriginal and Torres Strait Islander Australians With CKD

Aboriginal and Torres Strait Islander Australians (Indigenous Australians) suffer some of the highest rates of chronic kidney disease (CKD) in the world. Among Indigenous Australians in remote areas of the Northern Territory, prevalence rates for renal replacement therapy (RRT) are up to 30 times higher than national prevalence. Anemia among patients with CKD is a common complication. Iron deficiency is one of the major causes. Iron deficiency is also one of the key causes of poor response to the mainstay of anemia therapy with erythropoiesis-stimulating agents (ESAs). Therefore, the effective management of anemia in people with CKD is largely dependent on effective identification and correction of iron deficiency. The current identification of iron deficiency in routine clinical practice is dependent on 2 surrogate markers of iron status: serum ferritin concentration and transferrin saturation (TSAT). However, questions exist regarding the use of serum ferritin concentration in people with CKD because it is an acute-phase reactant that can be raised in the context of acute and chronic inflammation. Serum ferritin concentration among Indigenous Australians receiving RRT is often markedly elevated and falls outside reference ranges within most national and international guidelines for iron therapy for people with CKD. This review explores published data on the challenges of managing anemia in Indigenous people with CKD and the need for future research on the efficacy and safety of treatment of anemia of CKD in patients with high ferritin and evidence iron deficiency.

Assessing the Association between Serum Ferritin, Transferrin Saturation, and C-Reactive Protein in Northern Territory Indigenous Australian Patients with High Serum Ferritin on Maintenance Haemodialysis

Objective. To determine the significance of high serum ferritin observed in Indigenous Australian patients on maintenance haemodialysis in the Northern Territory, we assessed the relationship between ferritin and transferrin saturation (TSAT) as measures of iron status and ferritin and C-reactive protein (CRP) as markers of inflammation. Methods. We performed a retrospective cohort analysis of data from adult patients (≥18 years) on maintenance haemodialysis (>3 months) from 2004 to 2011. Results. There were 1568 patients. The mean age was 53.9 (11.9) years. 1244 (79.3%) were Indigenous. 44.2% (n = 693) were male. Indigenous patients were younger (mean age [52.3 (11.1) versus 57.4 (15.2), p < 0.001]) and had higher CRP [14.7 mg/l (7–35) versus 5.9 mg/l (1.9–17.5), p < 0.001], higher median serum ferritin [1069 µg/l (668–1522) versus 794.9 µg/l (558.5–1252.0), p < 0.001], but similar transferrin saturation [26% (19–37) versus 28% (20–38), p = 0.516]. We observed a small positive correlation between ferritin and TSAT (r² = 0.11, p < 0.001), no correlation between ferritin and CRP (r² = 0.001, p < 0.001), and positive association between high serum ferritin and TSAT (p < 0.001), Indigenous ethnicity (p < 0.001), urea reduction ratio (p = 0.001), and gender (p < 0.001) after adjustment in mixed regression analysis. Conclusion. Serum ferritin and TSAT may inadequately reflect iron status in this population. The high ferritin was poorly explained by inflammation.

Using Soluble Transferrin Receptor and Taking Inflammation into Account When Defining Serum Ferritin Cutoffs Improved the Diagnosis of Iron Deficiency in a Group of Canadian Preschool Inuit Children from Nunavik

The prevalence of iron depletion, iron deficient erythropoiesis (IDE), and iron deficiency anemia (IDA) was assessed in preschool Inuit children using soluble transferrin receptor (sTfR) and traditional indicators of iron status while disregarding or taking inflammation into account when defining SF cutoffs. Iron depletion was defined as follows: (1) SF < 15 μg/L regardless of the C-reactive protein (CRP) level and (2) SF < 15 or <50 μg/L with CRP ≤ 5 or >5 mg/L, respectively. IDE corresponded to iron depletion combined with total iron binding capacity > 72 μmol/L and/or transferrin saturation < 16%. Iron depletion and IDE affected almost half of the children when accounting for inflammation, compared to one-third when the SF cutoff was defined regardless of CRP level (P < 0.0001). The prevalence of IDE adjusted for inflammation (45.1%) was very similar to the prevalence observed when sTfR was used as a sole marker of IDE (47.4%). The prevalence of anemia was 15%. The prevalence of IDA (IDE + hemoglobin < 110 g/L) was higher when accounting for than when disregarding inflammation (8.0% versus 6.2%, P = 0.083). Using sTfR and different SF cutoffs for children with versus without inflammation improved the diagnosis of iron depletion and IDE. Our results confirm that Inuit children are at particularly high risk for iron deficiency.

Inflammation, high ferritin, and erythropoietin resistance in indigenous maintenance hemodialysis patients from the Top End of Northern Australia

Use of erythropoiesis-stimulating agents (ESAs) has improved the management of anemia in patients on maintenance hemodialysis (MHD). Iron deficiency and inflammation cause ESAs resistance and are both common among indigenous people of Northern Australia. As part of quality assurance in our Renal Anaemia Management program, we observed that there was use of higher doses of ESAs and adjuvant iron therapy in our MHD patients. This study aimed to explore the relationship among iron studies, inflammation, ESA responsiveness, and ESAs and iron requirements in indigenous patients on MHD from the Top End of Northern Australia. We performed a retrospective cohort analysis of anemia management in a cohort of our patients on MHD. We extracted data for 178 indigenous and 19 non-indigenous patients from 1 March 2009 to 28 February 2010 from the Renal Anaemia Management database, which collects data prospectively in MHD patients. Ninety-nine percent of the whole sample had a ferritin level above the international guidelines threshold of >500 µg/L. Indigenous patients had higher ferritin (1534 ± 245.5 µg/L vs. 1013 ± 323.3 µg/L, P = 0.002). C-reactive protein (CRP) was high in 56.9% of the total cohort. One hundred percent of those with normal CRP had high ferritin (>500 µg/L). C-reactive protein was higher in indigenous than in non-indigenous patients. Erythropoiesis-stimulating agents hyporesponsiveness was higher in indigenous patients (P < 0.0001). There was no significant difference in ESAs hyporesponsiveness among different levels of CRP (P = 0.116), ferritin (P = 0.408), and transferrin saturation (P = 0.503). Indigenous patients required higher total iron dose (2820.30 [2000-4350] vs. 2336.12 [1912-2900], P = 0.02). There was no significant relationship between the high ferritin and CRP. In indigenous dialysis patients, iron therapy and ESAs use are higher. The high iron use is due to a lack of published evidence to guide the administration of iron in patients with high ferritin. The high ferritin and ESAs resistance could not be fully explained by inflammation and need further evaluation. Further studies are required to determine the safe use of iron and management of ESAs resistance in our hemodialysis population.

Iron deficiency in children with global developmental delay and autism spectrum disorder

AIM

To investigate the prevalence of and risk factors for iron deficiency in children with global developmental delay and/or autism spectrum disorder (ASD).

METHOD

A retrospective review was conducted of the files of children referred to community paediatric clinics in South West Sydney from May 2009 to July 2011 who were diagnosed with global developmental delay and/or ASD. Data were extracted on iron studies and potential risk factors. Data were analysed using Pearson's ÷(2) -test and Fisher's exact test.

RESULTS

Subjects included 122 children. The prevalence of iron depletion was 2.5% (95% CI 0.5-7.0%); that of iron deficiency was 6.6% (95% CI 2.9-12.5%), and that of iron deficiency anaemia was 4.1% (95% CI 1.3-9.3%). In children with global developmental delay without ASD, the prevalence of iron depletion was 1.8% (95% CI 0-9.7%), that of iron deficiency 5.5% (95% CI 1.1-15.1%) and that of iron deficiency anaemia 5.5% (95% CI 1.1-15.1%). In children with ASD with or without global developmental delay, the prevalence of iron depletion was 3.0% (95% CI 0.4-10.4%), that of iron deficiency 7.5% (95% CI 2.5-16.6%) and that of iron deficiency anaemia 3.0% (95% CI 0.4-10.4%). Univariate analysis demonstrated three significant potential risk factors for iron depletion, iron deficiency and iron deficiency anaemia: problems sucking, swallowing or chewing (P = 0.002); poor eating behaviour (P = 0.008); and inadequate amounts of meat, chicken, eggs or fish (P = 0.002).

CONCLUSION

Iron deficiency and iron deficiency anaemia were more common in this clinical sample of children with global developmental delay and/or ASD than in the general population.

Iron supplementation for breath-holding attacks in children

BACKGROUND

Breath-holding attacks are common during childhood. Iron supplementation has been claimed to reduce the frequency or severity, or both, of breath-holding attacks in children.

OBJECTIVES

To assess the effect of iron supplementation on the frequency and severity of breath-holding attacks in children.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE, PsycINFO, CINAHL and the metaRegister of Controlled Trials (up to April 2009). We scanned references of included trials. Pharmaceutical companies manufacturing oral iron supplements and some trial authors were contacted for any unpublished data or trials.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing iron supplementation with placebo or no therapy in children < 18 years with recurrent (more than three) breath-holding episodes. These were reported by an observer.

DATA COLLECTION AND ANALYSIS

The primary outcome was reduction in the frequency (number over time) or severity (leading to cessation of loss of consciousness or convulsive movements), or both, of breath-holding attacks. Two authors (AZ and NO) independently selected studies and extracted data. Study authors were contacted for missing data, where necessary. Risk of bias was assessed using domain-based evaluation. In the presence of low heterogeneity, a fixed-effect meta-analysis was performed with pooled results presented as odds ratios (OR) and 95% confidence intervals (CIs).

MAIN RESULTS

Two trials (87 children) fulfilled the inclusion criteria. In these trials, iron supplementation significantly reduced the frequency of breath-holding attacks in children (OR 76.48; 95% CI 15.65 to 373.72; P < 0.00001). A meta-analysis that solely examined iron supplementation causing complete resolution of breath-holding attacks maintained this significance (OR 53.43; 95% CI 6.57 to 434.57; P = 0.0002).

AUTHORS' CONCLUSIONS

Iron supplementation (at 5 mg/kg/day of elemental iron for 16 weeks) appears to be useful in reducing the frequency and severity of breath-holding attacks. Supplementation is of particular benefit in children with iron deficiency anaemia, responses correlating with the improvements in haemoglobin values. Iron may still be of assistance in children who are not anaemic or who have low, normal haemoglobin levels. Further high-quality randomised control trials of iron supplementation to treat breath-holding attacks in children are required.

Short-term micronutrient supplementation reduces the duration of pneumonia and diarrheal episodes in HIV-infected children

The duration of pneumonia and of diarrhea is reported to be longer in HIV-infected than in uninfected children. We assessed the effect of a multi-micronutrient supplement on the duration of hospitalization in HIV-infected children. In a double-blind, randomized trial, HIV-infected children (4-24 mo) who were hospitalized with diarrhea or pneumonia were enrolled (n = 118) and given a daily dose of a multi-micronutrient supplement (containing vitamins A, B complex, C, D, E, and folic acid, as well as copper, iron, and zinc at levels based on recommended daily allowances) or a placebo until discharge from the hospital. Children's weights and heights were measured after enrollment and micronutrient concentrations were measured before discharge. On recovery from diarrhea or pneumonia, the children were discharged and the duration of hospitalization was noted. Anthropometric indices and micronutrient concentrations did not differ between children who received supplements and those who received placebos. Overall, the duration of hospitalization was shorter (P < 0.05) among children who were receiving supplements (7.3 +/- 3.9 d) (mean +/- SD) than in children who were receiving placebos (9.0 +/- 4.9); this was independent of admission diagnosis. In children admitted with diarrhea, the duration of hospitalization was 1.6 d (19%) shorter among children receiving supplements than in those receiving placebos, and hospitalization for pneumonia was 1.9 d (20%) shorter among children receiving supplements. Short-term multi-micronutrient supplementation significantly reduced the duration of pneumonia or diarrhea in HIV-infected children who were not yet receiving antiretroviral therapy and who remained alive during hospitalization.

Effectiveness of a large-scale iron-fortified milk distribution program on anemia and iron deficiency in low-income young children in Mexico

BACKGROUND

Anemia during infancy impairs neurodevelopment. Little information has been published about the effectiveness of large-scale programs on anemia and iron-deficiency prevention.

OBJECTIVE

The objective was to assess the effectiveness of a large-scale program that distributes subsidized iron-fortified milk in Mexico on anemia and iron deficiency in children aged 12-30 mo.

DESIGN

A double-blinded, group-randomized effectiveness trial was conducted in 12 milk distribution clusters assigned to consume iron-fortified (FM; n = 7) or nonfortified (NFM; n = 5) milk. A daily portion of FM contained 5.28 mg Fe (ferrous gluconate) and 48 mg sodium ascorbate.

RESULTS

Overall treatment effects were documented at 6 and 12 mo for anemia and for iron deficiency assessed by both serum ferritin (SF) and serum soluble transferrin receptor (sTfR) (interaction: P < 0.10). Differential effects at 6 mo (P = 0.004) and 12 mo (P = 0.664) were documented only for sTfR. Estimated prevalences (EPs) of anemia (hemoglobin < 110 g/L) from baseline to 6 and 12 mo decreased from 42.6% to 19.7% and 9.4%, respectively, in the NFM group (n = 210) and from 44.5% to 12.7% and 4.0%, respectively, in the FM group (n = 357). EPs of SF < 12 mug/L from baseline to 6 and 12 mo changed from 36.0% to 41.8% and 17.1%, respectively, in the NFM group (n = 43) and from 29.8% to 18.6% and 5.7%, respectively, in the FM group (n = 144). EPs of sTfR > 3.3 mg/L from baseline to 6 and 12 mo decreased from 16.2% to 8.3% and 2.0%, respectively, in the NFM group (n = 114) and from 15.5% to 0.7% and 1.1%, respectively, in the FM group.

CONCLUSION

A large-scale iron-fortified subsidized-milk program was effective at reducing the rates of anemia and iron deficiency in Mexican children during 12 mo of implementation. This trial was registered at clinicaltrials.gov as NCT00508131.

Pediatric reference intervals for soluble transferrin receptor and transferrin receptor-ferritin index

BACKGROUND

Recent studies showing an improved diagnosis of iron deficiency (ID) with soluble transferrin receptor (sTfR) and sTfR-ferritin index did not take into account the age-dependency of sTfR and ferritin. Moreover, there is a paucity of data on pediatric reference intervals for sTfR and sTfR-ferritin index.

METHODS

A study cohort of 436 apparently healthy children was analyzed to establish reference intervals for ferritin, transferrin, sTfR and sTfR-ferritin index. To account for age-dependency, standard deviation scores (Z-scores) for these markers were calculated. The association between these parameters and C-reactive protein (CRP) was analyzed.

RESULTS

The Z-scores of ferritin, transferrin and sTfR had a significant association with CRP, whereas the Z-score of sTfR-ferritin did not correlate with CRP. The reference intervals of these parameters were reported.

CONCLUSION

Among the different markers of ID, the Z-scores of sTfR, transferrin and ferritin, but not sTfR-ferritin index, associate with the inflammatory status.

Policy statement on iron deficiency in pre-school-aged children

AIM

We aimed to develop policy in relation to three areas: (i) the diagnosis of iron deficiency; (ii) maternal-infant issues and the prevention of iron deficiency; and (iii) the treatment of iron deficiency.

METHODS

Within each of these topic areas we completed a literature review and developed recommendations to help direct activities of the Royal Australasian College of Physicians, update paediatricians and guide clinical practice.

RESULTS

Iron deficiency can be defined using cut-off values for laboratory measures of iron status or, if an intercurrent infection is not present, by demonstrating a response to a therapeutic trial of iron. The appropriate measures of iron status vary depending upon the presence of intercurrent infection. Full-term babies are born with iron stores sufficient to meet their needs to age 4-6 months but premature infants are not. After age 6 months infants are dependent upon dietary iron from complementary foods even with continued breastfeeding. Infants <33 weeks gestation or <1800 g birthweight should receive iron from 4 weeks of age. In most settings recommended treatment of iron deficiency is with oral ferrous sulphate as a single or twice daily dose of between 3 and 6 mg/kg/day.

CONCLUSIONS

Iron deficiency is prevalent and an important determinant of child health. Precise and accurate diagnosis remains challenging. Iron supplementation is required for premature and low-birthweight infants. Oral iron salts remain the recommended treatment of choice in most instances.

The effect of iron fortification and de-worming on anaemia and iron status of Vietnamese schoolchildren

Previous data from Vietnam show that anaemia is highly prevalent among schoolchildren, who are considered not to be iron deficient.Trichurisinfection doubled the risk of anaemia. The present study aimed to evaluate the hypothesis that de-worming is more effective than iron fortification in an anaemic, infection-prone population. In a trial with a 2 × 2 factorial design, 425 anaemic children aged 6–8 years were randomly assigned to receive either iron-fortified noodles or placebo, and mebendazole or placebo. Outcomes considered were change in haematological indicators of iron status (Hb, serum ferritin (SF), serum transferrin receptor (TfR) and haemoglobinopathies analysis); inflammations (C-reactive protein (CRP)); parasite infection status (hookworm,TrichurisandAscarisinfection); and IgE. ANOVA and logistic regression were used to assess the effects of iron fortification and de-worming on Hb, SF, TfR, body iron and anaemia. Hb improved in all groups after 6 months of intervention. Iron fortification significantly improved Hb, SF and body iron (2·6 g/l, 16·3 μg/l and 1 mg/kg, respectively). Prevalence of elevated IgE was very high at baseline (99 %) and significantly reduced to about 75 % in all groups after intervention. De-worming unexpectedly showed no effect on Hb, iron status and IgE level. It is concluded that iron fortification slightly improved anaemia and iron status in anaemic schoolchildren in rural Vietnam that were not considered iron deficient. Chronic infection or other unidentified factors may play an important role in the seasonal reduction of anaemia seen in all treatment groups.

Critical appraisal of the management of severe malnutrition: 2. Dietary management

In the dietary management of severe acute malnutrition in children, there is evidence to support the WHO Manual's protocol of cautious feeding of a low energy and protein formula with small frequent feeds in the initial phase of treatment, particularly in kwashiorkor. However, this initial milk diet (WHO F-75) might benefit from increasing the sulphur amino acid, phosphorus and potassium content and reducing the lactose content, but further studies are needed. Careful tube-feeding results in faster initial recovery and weight gain, but has a significant risk of aspiration in poorly supervised settings. Ready-to-use therapeutic food is an important recent advance in the dietary management of malnutrition in ambulatory settings, allowing more effective prevention programmes and earlier discharge from hospital where community follow-up is available. It should be included in future protocols. There is very good evidence on the use of micronutrients such as zinc, and preliminary evidence suggests that smaller doses of daily vitamin A are preferable to a single large dose on admission for severe malnutrition.

Iron deficiency and anemia prevalence and associated etiologic risk factors in First Nations and Inuit communities in Northern Ontario and Nunavut

BACKGROUND

Anemia is common among children in Aboriginal communities in Canada. The objectives of this study were to determine the prevalence of anemia and to identify its associated risk factors among young children in Aboriginal communities in northern Ontario and Nunavut.

METHODS

115 children from one Inuit and two Cree First Nations communities participated. We collected information on demographic and dietary factors and measured hemoglobin (Hb), ferritin (SF), serum transferrin receptor (sTfR) and Helicobacter pylori IgG antibodies. Odds ratios and 95% confidence intervals were determined to examine risk factors associated with anemia and iron deficiency (ID) and further analyzed using stepwise regression procedures.

RESULTS

Prevalence of anemia (Hb<110 g/L) was 36.0%. Iron deficiency (sTfR>8.5 mg/L) was present in 27.6% of the study population. Approximately 53.3% had depleted iron stores (SF<12 microg/L). Consumption of cow/evaporated milk was the only independent risk factor associated with anemia. Infection with H. pylori and prolonged consumption of breastmilk were also associated, although not independently, with anemia. Formula intake was negatively associated with ID.

INTERPRETATION

The prevalence of anemia in Aboriginal children was eight times higher than among similar populations in urban Canada and was especially high among Inuit children. ID was the major cause of anemia, but not the only one, since 10% of anemic children were not iron deficient. Given that the consumption of cow/evaporated milk was found to be a significant independent risk factor associated with anemia, public health strategies should include promotion of breastfeeding, combined with iron-rich complementary foods, while addressing socio-economic conditions that may be preventing these practices from being adopted. H. pylori may be a major contributing factor to anemia, thus improvements in water quality and sanitation also need to be considered.

Serum transferrin receptor and zinc protoporphyrin as indicators of iron status in African children

BACKGROUND

Although transferrin receptor (TfR) and zinc protoporphyrin (ZnPP) are often used to define iron status in school-age children in developing countries, the diagnostic cutoffs for this age group are uncertain.

OBJECTIVE

The objective was to determine the sensitivity and specificity of TfR and ZnPP in predicting iron deficiency in black and white children in Africa.

DESIGN

Hemoglobin, C-reactive protein (CRP), serum ferritin (SF), TfR, and ZnPP were measured in children in Côte d'Ivoire and Morocco. We excluded children with elevated CRP and then used receiver operating characteristic (ROC) curves to evaluate TfR and ZnPP alone and in combination in screening for iron deficiency, defined as an SF concentration <15 mug/L, and iron deficiency anemia (IDA), defined as an SF concentration <15 mug/L and low hemoglobin.

RESULTS

The sample included 2814 children aged 5-15 y. The sensitivity and specificity of TfR and ZnPP were limited by considerable overlap between iron-sufficient, nonanemic children and those with IDA. On the basis of ROC curves, we identified diagnostic cutoffs for TfR and ZnPP that achieved specificities and sensitivities of approximately 60-80%. Separate cutoffs for Côte d'Ivoire and Morocco gave the best performance; the cutoffs for both TfR and ZnPP were higher in Côte d'Ivoire. Moreover, a comparison of nonanemic, iron-sufficient subjects showed that Ivorian children had significantly higher TfR and ZnPP concentrations than did Moroccan children (P < 0.01).

CONCLUSIONS

New diagnostic cutoffs for TfR and ZnPP, based on ROC curve analyses, may improve the performance of these indexes in defining iron status in children. Significant ethnic differences in TfR and ZnPP suggest that separate cutoffs may be needed for black and white children.