Pre-discharge iron status and its determinants in premature infants

Growth and micronutrient status parameters of Nigerian preterm infants consuming preterm formula or breastmilk

BACKGROUND

Moderate-to-late preterm infants (32-34 weeks GA) have increased risk of neonatal morbidities compared to term infants, however dedicated nutritional guidelines are lacking.

METHODS

Moderate-to-late preterm infants received a preterm formula (n = 17) or breastmilk (n = 24) from age 2-10 weeks in a non-randomized, open-label observational study. Anthropometric measurements were assessed bi-weekly. Blood concentrations of hemoglobin, ferritin, serum retinol, and 25-hydroxy-vitamin D (25OHD) were analyzed at age 2 and 10 weeks.

RESULT

Average growth per day was 14.7 g/kg BW/day in formula-fed and 12.8 g/kg BW/day in breastmilk-fed infants but not different from each other. Length and head circumference in both groups were in line with the median reference values of the Fenton growth chart. At 10 weeks of age, hemoglobin tended to be higher in the formula-fed group (10.2 g/dL vs. 9.6 g/dL, p = 0.053). 25OHD increased in formula- and breastmilk-fed infants from 73.8 to 180.9 nmol/L and from 70.7 to 97.6 nmol/L, respectively. Serum retinol only increased in the formula-fed group (0.63 to 1.02 µmol/L, p < 0.001).

CONCLUSION

Breastfeeding resulted in adequate growth in moderate-late preterm infants but was limiting in some micronutrients. The preterm formula provided adequate micronutrients, but weight gain velocity was higher than the Fenton reference value.

IMPACT STATEMENT

Unfortified breastmilk resulted in adequate growth in weight, length and head circumference in Nigerian moderate to late preterm infants during an study period of 8 weeks, but status of vitamin D, vitamin A and iron needs to be monitored. The high-energy formula, developed for very preterm infants, resulted in higher growth in body weight in moderate to late preterm infants than the median of the Fenton preterm growth chart. This study supports the necessity of dedicated nutritional guidelines, and regular monitoring of growth and nutritional status of moderate to late preterm infants.

Ferritin in pediatric critical illness: a scoping review

This scoping review aimed to elucidate and summarize the predictive role of serum ferritin in critical pediatric illness. The Preferred Reporting Items for Systematic reviews and Meta-Analyses methodology was employed to conduct a scoping review of 5 databases (MEDLINE, CENTRAL, ProQuest, ScienceDirect, and Epistemonikos) from the date of inception through January 24, 2022. Primary research studies involving subjects aged <18 years and serum ferritin levels were screened and reviewed independently following an a priori defined protocol. Of the 1,580 retrieved studies, 66 were analyzed. Summary statistics of serum ferritin levels for overall and condition-specific studies were reported in 30 (45.4%) and 47 studies (71.2%), respectively. The normal range was defined in 16 studies (24.2%), whereas the threshold was determined in 43 studies (65.1%). A value of <500 ng/mL was most often the upper limit of the normal range. Serum ferritin as a numerical variable (78.9%) was usually significantly higher (80.8%) in the predicted condition than in controls, while as a categorical variable with preset thresholds, ferritin was a significant predictor in 84.6% of studies. A total of 22 predictive thresholds predicted mortality (12 of 46 [26.1%]), morbidity (18 of 46 [39.1%]), and specific (16 of 46 [34.8%]) outcomes in 15 unique conditions. Increased precision in serum ferritin measures followed by close attention to the threshold modeling strategy and reporting can accelerate the translation from evidence to clinical practice.

Welder's Anthrax: A Tale of 2 Cases

Bacillus anthracis has traditionally been considered the etiologic agent of anthrax. However, anthrax-like illness has been documented in welders and other metal workers infected with Bacillus cereus group spp. harboring pXO1 virulence genes that produce anthrax toxins. We present 2 recent cases of severe pneumonia in welders with B. cereus group infections and discuss potential risk factors for infection and treatment options, including antitoxin.

Postdischarge Iron Status in Very Preterm Infants Receiving Prophylactic Iron Supplementation after Birth

OBJECTIVE

To determine postdischarge iron status and associated factors in very preterm infants.

STUDY DESIGN

A retrospective cohort study was conducted through a provincial database on all very preterm infants born in Nova Scotia between 2005 and 2018. As a standard of care, all infants received prophylactic iron supplements starting at 2-4 weeks of chronological age and were tested for iron deficiency at 4 or 6 months corrected age. Iron deficiency was defined as serum ferritin <20 g/L at 4 months or <12 g/L at 6 months. Multivariate logistic regression analysis identified factors associated with iron deficiency.

RESULTS

Among 411 infants, 132 (32.1%) had iron deficiency and 11 (2.7%) had iron deficiency anemia. The prevalence of iron deficiency decreased over time, from 37.6% in 2005-2011 to 25.8% in 2012-2018. Gestational hypertension in the mother (P = .01) and gestational age <27 weeks (P = .02) were independent risk factors for iron deficiency. In addition, the odds of iron deficiency were lower in the mixed-fed group (ie, with breast milk and formula combined) compared with the exclusive formula-fed group (P = .01).

CONCLUSIONS

Iron deficiency was prevalent in 32% of the very preterm infants despite early iron prophylaxis. These results demonstrate the importance of monitoring iron stores during preterm follow-up. Information about risk factors is important to mitigate iron deficiency in very preterm infants.

Effect of Daily Iron Supplementation on Infantile Iron Homeostasis in Preterm Infants

Objective: The aim of this study was to investigate the effects of unified iron supplementation and identify the factors related to the iron homeostasis among preterm infants. Method: A total of 250 preterm infants were divided into neonatal anemic (NA, n = 154) and non-neonatal anemic group (NNA, n = 96). Iron supplements at a dose of 2 mg/kg per day were given from 40 weeks' gestational age to 6 months. Iron status parameters were measured at 3 and 6 months, respectively. Prevalence of iron deficiency (ID) and iron deficiency anemia (IDA), and the correlated factors were analyzed. Growth and side-effects were monitored. Results: There were no significant differences for the prevalence of ID or IDA between the two groups. Multivariate regression analyses showed that higher Hb at birth and early treatment of blood transfusion reduced the risk of ID/IDA at 3 months (all p < 0.05); while higher level of Hb at 3 months (p = 0.004) and formula feeding reduced the occurrence of ID/IDA at 6 months (p < 0.05); males had a 3.35 times higher risk to develop ID/IDA than girls (p = 0.021). No differences in growth and side effects were found. Conclusion: A daily dose of 2 mg/kg iron supplement is beneficial to maintain iron homeostasis in majority preterm infants within 6 months regardless of their neonatal anemia history. Under the routine iron supplementation, Hb level at birth and at 3 months, early treatment of blood transfusion, gender and feeding patterns are the major factors affecting the prevalence of ID/IDA among preterm infants in infancy.

High Prevalence of Iron Deficiency Despite Standardized High-Dose Iron Supplementation During Recombinant Erythropoietin Therapy in Extremely Low Gestational Age Newborns

OBJECTIVE

To assess the effects of protocolized recombinant human erythropoietin (r-HuEPO) therapy and standardized high dose iron supplementation on hematologic and iron status measures in a cohort of extremely low gestational age newborns (ELGANs).

STUDY DESIGN

Charts of extremely low gestational age newborns admitted from 2006 to 2016 and who had received r-HuEPO per neonatal intensive care unit protocol were reviewed. The r-HuEPO was started at a dose of 900 IU/kg per week after 7 days of age and continued until 35 weeks postmenstrual age. Oral iron supplementation at 6-12 mg/kg per day was used to maintain a transferrin saturation of >20% during r-HuEPO treatment. Data on demographic features, hematologic and iron panel indices, red blood cell transfusions, and clinical outcomes were collected. Quartile groups were created based on serum ferritin levels at the conclusion of the r-HuEPO treatment and the quartiles were compared.

RESULTS

The cohort included 116 infants with mean gestational age 25.8 ± 1.5 weeks and birth weight 793 ± 174.1 g. The r-HuEPO promoted erythropoiesis as indicated by increasing hemoglobin, hematocrit, and reticulocyte count. Serum ferritin decreased over time and was ≤75 ng/mL in 60.2% of infants at the conclusion of r-HuEPO therapy; 87% received packed red blood cell transfusions. Transfusion volume, total iron intake, total iron binding capacity, and transferrin concentration differed among infants in the different serum ferritin quartiles (P < .05).

CONCLUSIONS

In extremely low gestational age newborns, r-HuEPO therapy promoted erythropoiesis. Despite a biomarker-based standardized high-dose iron supplementation, the majority of infants had evidence of iron deficiency to a degree that is associated with reduced brain function.

Reticulocyte hemoglobin content as a function of iron stores at 35-36 weeks post menstrual age in very premature infants

BACKGROUND

Premature infants are born with lower iron stores and are at risk for iron deficiency during early infancy. To prevent iron deficiency, premature infants are routinely supplemented with 2 mg/kg/day oral elemental iron. Reticulocyte hemoglobin content (RET-He), a measure of iron deficiency, has not been well evaluated prior to discharge in premature infants.

OBJECTIVES

Our objectives were to evaluate RET-He and its correlation with serum ferritin (SF), an index of iron stores, at 35-36 weeks postmenstrual age (PMA) in ≤32 weeks gestational age (GA) infants.

METHODS

We performed a prospective nested study involving 24-32 weeks GA infants who were receiving 2 mg/kg/day oral elemental iron with full enteral feedings at 35-36 weeks PMA. Infants with the following conditions were excluded: craniofacial malformation, chromosomal disorders, TORCH (toxoplasmosis, other infections, rubella, cytomegalovirus, and herpes simplex), culture-proven sepsis, C-reactive protein >5 mg/l within 10 days of iron status assessment, or erythropoietin therapy. SF and RET-He were measured at 35-36 weeks PMA using chemiluminescence immunoassay and Sysmex XN hematology analyzer, respectively. RET-He <27 pg was deemed indicative of iron deficiency.

RESULTS

Ninety-eight infants were studied, of which 21 infants had RET-He <27 pg. There was a positive correlation between RET-He and SF (coefficient 0.22, p = .03) that remained significant after controlling for GA (coefficient 0.21, p = .03) and frequency of prior erythrocyte transfusions (coefficient 0.21, p = .03). On stratified analysis, there was a positive correlation between SF and RET-He in females (N = 52, coefficient 0.23, p = .02), but not in males (N = 46, coefficient 0.05).

CONCLUSIONS

Most premature infants receiving 2 mg/kg/day oral elemental iron are iron replete for erythropoiesis at 35-36 weeks PMA. RET-He increases with an increase in iron stores, suggesting that additional iron supplementation prior to discharge to very premature infants with borderline low RET-He may help prevent iron deficiency during early infancy.

Iron Deficiency and Iron Homeostasis in Low Birth Weight Preterm Infants: A Systematic Review

Iron is an essential micronutrient that is involved in many functions in humans, as it plays a critical role in the growth and development of the central nervous system, among others. Premature and low birth weight infants have higher iron requirements due to increased postnatal growth compared to that of term infants and are, therefore, susceptible to a higher risk of developing iron deficiency or iron deficiency anemia. Notwithstanding, excess iron could affect organ development during the postnatal period, particularly in premature infants that have an immature and undeveloped antioxidant system. It is important, therefore, to perform a review and analyze the effects of iron status on the growth of premature infants. This is a transversal descriptive study of retrieved reports in the scientific literature by a systematic technique. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were adapted for the review strategy. The inclusion criteria for the studies were made using the PICO (population, intervention, comparison, outcome) model. Consequently, the systematic reviews that included studies published between 2008–2018 were evaluated based on the impact of iron status on parameters of growth and development in preterm infants.

Latent iron deficiency at birth influences auditory neural maturation in late preterm and term infants

BACKGROUND

In utero latent iron deficiency has been associated with abnormal neurodevelopmental outcomes during childhood. Its concomitant effect on auditory neural maturation has not been well studied in late preterm and term infants.

OBJECTIVE

The objective was to determine whether in utero iron status is associated with auditory neural maturation in late preterm and term infants.

DESIGN

This prospective cohort study was performed at Sir Ganga Ram Hospital, New Delhi, India. Infants with a gestational age ≥34 wk were eligible unless they met the exclusion criteria: craniofacial anomalies, chromosomal disorders, hemolytic disease, multiple gestation, third-trimester maternal infection, chorioamnionitis, toxoplasmosis, other infections, rubella, cytomegalovirus infection, and herpes simplex virus infections (TORCH), Apgar score <5 at 5 min, sepsis, cord blood not collected, or auditory evaluation unable to be performed. Sixty consecutive infants with risk factors for iron deficiency, such as small for gestational age and maternal diabetes, and 30 without risk factors for iron deficiency were enrolled. Absolute wave latencies and interpeak latencies, evaluated by auditory brainstem response within 48 h after birth, were measured and compared between infants with latent iron deficiency (serum ferritin ≤75 ng/mL) and infants with normal iron status (serum ferritin >75 ng/mL) at birth.

RESULTS

Twenty-three infants had latent iron deficiency. Infants with latent iron deficiency had significantly prolonged wave V latencies (7.10 ± 0.68 compared with 6.60 ± 0.66), III-V interpeak latencies (2.37 ± 0.64 compared with 2.07 ± 0.33), and I-V interpeak latencies (5.10 ± 0.57 compared with 4.72 ± 0.56) compared with infants with normal iron status (P < 0.05). This difference remained significant on regression analyses after control for confounders. No difference was noted between latencies I and III and interpeak latencies I-III.

CONCLUSION

Latent iron deficiency is associated with abnormal auditory neural maturation in infants at ≥34 wk gestational age. This trial was registered at clinicaltrials.gov as NCT02503397.

On the source of the non-transferrin-bound iron which accumulates in packed red blood cell units during storage

BACKGROUND

Recent studies have shown large increases in non-transferrin-bound iron (NTBI) and biomarkers of oxidative stress in the extracellular medium of packed red blood cell units during storage. It has been further suggested that transfusion-mediated iron and oxidative load may contribute to transfusion-related morbidity in premature babies. The origin and nature of the NTBI is currently unclear, but the release of iron from oxidatively modified haemoglobin and haem has been suggested. The purpose of this study was to investigate whether this may be the case.

MATERIALS AND METHODS

The concentration of haem in the extracellular fluid of paediatric packed cell units stored from 3 to 35 days was measured using a commercial haem assay. In vitro studies were conducted using haem (haemin; ferriprotoporphyrin IX chloride) to determine whether the NTBI assay was able to react with and measure iron associated with haem in the presence and absence of oxidising agents.

RESULTS

The level of haem in the extracellular fluid of paediatric packed cell units rose gradually from day 3 to day 21, then more rapidly to day 35. Very little NTBI was released from haem in the absence of oxidising agents, but the amount rose in a dose- and time-dependent manner in proportion to the oxidation of haem by incubation with H2O2.

DISCUSSION

The results of the study imply that the NTBI measured in previous studies may derive from the oxidatively modified haem that builds up in the extracellular fluid of packed red blood cell units during storage. The potential influence of this on transfusion mediated morbidity is discussed.