Bone isoenzyme of serum alkaline phosphatase and serum inorganic phosphate in metabolic bone disease of prematurity

Adherence to Nutritional Practice Guideline in Premature Infants: A Nationwide Survey in Taiwan

OBJECTIVES

This study aimed to assess the current neonatal nutritional practices in Taiwan and promote consensus on standardized protocols.

METHODS

An online questionnaire comprising 95 items on parenteral nutrition (PN) and enteral nutrition (EN) practices was distributed to neonatal care units across Taiwan via email between August and December 2022. The responses were compared with the recommendations from the European Society for Pediatric Gastroenterology Hepatology and Nutrition for preterm infant care.

RESULTS

Most of the 35 neonatal units, comprising 17 level III and 18 level II units, that participated in this study adhered to standard PN protocols; however, only 30% of units used protein-containing solutions as the initial fluid. Over half of the neonatal units provided calcium, phosphate, and magnesium at less than the recommended dosage. Trophic feeding commenced within 48 h in 88% of the units, with the mother's milk used as the first choice. All the units preferred commencing advanced feeding at <25 mL/kg/day.

CONCLUSIONS

Most nutrient protocols for preterm infants in neonatal units in Taiwan meet recent guidelines, but discrepancies such as lower mineral supplements in PN and a slower advancement of enteral feeding increase nutritional risk. These issues warrant further research.

Unsupervised Learning-Based Measurement of Ultrasonic Axial Transmission Velocity in Neonatal Bone

OBJECTIVES

To develop a robust algorithm for estimating ultrasonic axial transmission velocity from neonatal tibial bone, and to investigate the relationships between ultrasound velocity and neonatal anthropometric measurements as well as clinical biochemical markers of skeletal health.

METHODS

This study presents an unsupervised learning approach for the automatic detection of first arrival time and estimation of ultrasonic velocity from axial transmission waveforms, which potentially indicates bone quality. The proposed method combines the ReliefF algorithm and fuzzy C-means clustering. It was first validated using an in vitro dataset measured from a Sawbones phantom. It was subsequently applied on in vivo signals collected from 40 infants, comprising 21 males and 19 females. The extracted neonatal ultrasonic velocity was subjected to statistical analysis to explore correlations with the infants' anthropometric features and biochemical indicators.

RESULTS

The results of in vivo data analysis revealed significant correlations between the extracted ultrasonic velocity and the neonatal anthropometric measurements and biochemical markers. The velocity of first arrival signals showed good associations with body weight (ρ = 0.583, P value <.001), body length (ρ = 0.583, P value <.001), and gestational age (ρ = 0.557, P value <.001).

CONCLUSION

These findings suggest that fuzzy C-means clustering is highly effective in extracting ultrasonic propagating velocity in bone and reliably applicable in in vivo measurement. This work is a preliminary study that holds promise in advancing the development of a standardized ultrasonic tool for assessing neonatal bone health. Such advancements are crucial in the accurate diagnosis of bone growth disorders.

Metabolic bone disease of prematurity screening and individualized enteral mineral supplementation in high-risk neonates: a quality improvement initiative

OBJECTIVE

Prompted by an alarmingly low screening rate for metabolic bone disease of prematurity (MBDP), we aimed to increase MBDP screening with serum calcium, phosphorous, and alkaline phosphatase at four to six weeks of life in infants born at <1500 g and <32 gestational weeks from a baseline of 27.37% to 90% within one year.

STUDY DESIGN

We used the Institute for Healthcare Improvement's Model for Improvement as a framework. A key driver diagram informed the interventions which were carried out through four Plan-Do-Study-Act cycles.

RESULTS

There were 129 and 130 neonates in the pre-intervention baseline group and post-intervention MBDP bundle group, respectively. MBDP bundled primary screening rates increased from 27.37% to 95.56% (p < 0.001). Furthermore, 20% of infants had an individualized change in their enteral mineral supplementation after the initiative.

CONCLUSIONS

An interdisciplinary team-based quality improvement approach was effective in altering clinical practice to improve screening and subsequent treatment for MBDP.

Role of fibroblast growth factor-23 as an early marker of metabolic bone disease of prematurity

PURPOSE

Metabolic bone disease of prematurity (MBDP) remains a significant cause of morbidity in extremely premature newborns. In high-risk patients, suspected diagnosis and subsequent treatment modifications, with limitations in terms of sensitivity and specificity, rely on low phosphorus levels and/or high levels of alkaline phosphatase (ALP). We investigated the potential of fibroblast growth factor-23 (FGF23) as an early marker for MBDP when measured at 3-4 weeks of life in at-risk patients.

METHODS

A single-center prospective observational non-interventional study including preterm newborns of both sexes, with a gestational age of less than 32 weeks and/or a birth weight of less than 1500 g. In the standard biochemical screening for MBDP performed between 3 and 4 weeks of life within a nutritional profile, the determination of FGF23 was included along with other clinical and metabolic studies. The study was conducted at Marqués de Valdecilla University Hospital in Santander, Spain, from April 2020 to March 2021. Participants provided informed consent. Biochemical analyses were conducted using various platforms, and follow-up evaluations were performed at the discretion of neonatologists. Patients at high risk for MBDP received modifications in treatment accordingly. The sample was descriptively analyzed, presenting measures of central tendency and dispersion for continuous variables, and absolute numbers/percentages for categorical ones. Tests used included t-tests, Mann‒Whitney U tests, chi-square tests, logistic regressions, Pearson correlation, and ROC curve analysis (IBM SPSS Statistics version 19). Significance level: P < 0.05.

RESULTS

In the study involving 25 at-risk premature newborns, it was found that 20% (n = 5) were diagnosed with MBDP. Three of these patients (60%) were identified as high-risk based on standard biochemical evaluation at 3-4 weeks of age, while the other two patients (40%) were diagnosed in subsequent weeks. However, in all 5 patients, measurement of FGF23 levels would allow for early identification and optimization of treatment before other markers become altered. Low levels of FGF23 at 3-4 weeks, even with normal phosphorus and ALP levels, indicate the need for modifications in nutritional supplementation.

CONCLUSIONS

MBDP remains a significant concern in extremely premature newborns. Current diagnostic methods rely on limited biochemical markers. Early detection of low FGF23 levels enables timely interventions, potentially averting demineralization.

Real-time predictive model of extrauterine growth retardation in preterm infants with gestational age less than 32 weeks

The aim of this study was to develop a real-time risk prediction model for extrauterine growth retardation (EUGR). A total of 2514 very preterm infants were allocated into a training set and an external validation set. The most appropriate independent variables were screened using univariate analysis and Lasso regression with tenfold cross-validation, while the prediction model was designed using binary multivariate logistic regression. A visualization of the risk variables was created using a nomogram, while the calibration plot and receiver operating characteristic (ROC) curves were used to calibrate the prediction model. Clinical efficacy was assessed using the decision curve analysis (DCA) curves. Eight optimal predictors that namely birth weight, small for gestation age (SGA), hypertensive disease complicating pregnancy (HDCP), gestational diabetes mellitus (GDM), multiple births, cumulative duration of fasting, growth velocity and postnatal corticosteroids were introduced into the logistic regression equation to construct the EUGR prediction model. The area under the ROC curve of the training set and the external verification set was 83.1% and 84.6%, respectively. The calibration curve indicate that the model fits well. The DCA curve shows that the risk threshold for clinical application is 0-95% in both set. Introducing Birth weight, SGA, HDCP, GDM, Multiple births, Cumulative duration of fasting, Growth velocity and Postnatal corticosteroids into the nomogram increased its usefulness for predicting EUGR risk in very preterm infants.

Effect of early preventive supplementation with calcium and phosphorus on metabolic bone disease in premature infants

OBJECTIVE

The objective was to study the effect of early preventive calcium and phosphorus supplementation on metabolic bone disease in preterm infants.

METHODS

A retrospective analysis of 234 preterm infants with a gestational age < 32 weeks or birth weight < 1500 g who were hospitalized in the Neonatology Department of the Second Hospital of Shandong University from 01.2018 to 12.2020 was conducted. One hundred thirty-two premature infants hospitalized from 01.2018 to 06.2019 did not receive prophylactic calcium and phosphorus supplementation in the early postnatal period. These infants received calcium or phosphorus supplementation at the time of hypocalcaemia or hypophosphatemia diagnosis. One hundred two premature infants hospitalized from 07.2019 to 12.2020 received early preventive calcium and phosphorus supplementation after birth. The levels of serum calcium and phosphorus, alkaline phosphatase, 25-hydroxyvitamin D, calcitonin, and parathyroid hormone at different time points and growth indicators at six months of age were compared between the two groups of infants. The number of cases of metabolic bone disease and fracture between the two groups was compared.

RESULTS

1) A total of 12 infants (5.13%) among the 234 preterm infants were diagnosed with metabolic bone disease, including 2 (1.96%) in the prophylactic supplementation group and 10 (7.58%) in the nonprophylactic supplementation group. Fractures occurred in 3 premature infants (25.0%) with metabolic bone disease, all of whom were in the group that did not receive prophylactic supplementation. 2) There was no significant difference in serum calcium and calcitonin levels between the two groups. The levels of serum phosphorus and 25 hydroxyvitamin D in the prophylactic supplementation group were higher than those in the nonprophylactic supplementation group (P < 0.05). In comparison, alkaline phosphatase and parathyroid hormone levels were lower in the prophylactic supplementation group than in the nonprophylactic supplementation group (P < 0.05). Preterm infants in the prophylactic supplementation group had higher weight, length, head circumference, and bone density values than those in the nonprophylactic supplementation group (P < 0.05).

CONCLUSION

Preventive supplementation with calcium and phosphorus after birth can effectively improve calcium and phosphorus metabolism, and reduce the incidence of metabolic bone disease and fractures in premature infants. This can be further publicized and used clinically.

Characterisation of parathyroid hormone concentration in extremely preterm or very low birthweight infants in routine clinical screening for metabolic bone disease: A service evaluation cohort study

AIM

To characterise parathyroid hormone (PTH) concentrations in infants at high risk for metabolic bone disease, in order to assist clinical decisions around the use of PTH for screening.

METHODS

Infants born under 28 weeks' postmenstrual age or with birthweight under 1.5 kg in a tertiary neonatal unit in the UK were included. Clinical guidance was to assess PTH concentration in the first 3 weeks after birth. Clinical information was extracted from prospective records.

RESULTS

Sixty-four infants had mean birth gestation of 26 weeks and birthweight of 882 g. Median PTH (sent on median day 18 of life) was 9.2 pmol/L (interquartile range 5.3-17 pmol/L). Sixty-seven per cent of infants had a PTH greater than 7 pmol/L. For 22% of the infants, raised PTH was not accompanied by abnormal phosphate or alkaline phosphatase. Eighty-nine per cent of infants tested were insufficient or deficient for 25-hydroxyvitamin D.

CONCLUSIONS

Universal screening highlights the high frequency of high PTH in this high-risk population, implying a need for calcium supplementation. A considerable number of infants would not be identified as showing potential signs of metabolic bone disease if the assessment excludes the use of PTH. The high level of 25-hydroxyvitamin D deficiency may be a confounder.

Calcium and Phosphorus: All You Need to Know but Were Afraid to Ask

Inadequate intake of calcium and phosphorus during the perinatal period can result in metabolic bone disease (MBD), characterized by decreased bone mass, altered bone mineralization, and increased risk for fractures. Preterm neonates have higher risk of developing MBD. Treating MBD involves ensuring adequate calcium and phosphorus intake, early fortification, and vitamin D supplementation. Health care providers should closely monitor nutrient intake, postnatal growth, and screening of preterm neonates at risk for MBD. This review summarizes the critical roles of calcium and phosphorus in regulating bone physiology, how they regulate bone formation and resorption, and their influence on overall bone health.

Prenatal and Neonatal Bone Health: Updated Review on Early Identification of Newborns at High Risk for Osteopenia

Bone health starts with maternal health and nutrition, which influences bone mass and density already in utero. The mechanisms underlying the effect of the intrauterine environment on bone health are partly unknown but certainly include the 'foetal programming' of oxidative stress and endocrine systems, which influence later skeletal growth and development. With this narrative review, we describe the current evidence for identifying patients with risk factors for developing osteopenia, today's management of these populations, and screening and prevention programs based on gestational age, weight, and morbidity. Challenges for bone health prevention include the need for new technologies that are specific and applicable to pregnant women, the foetus, and, later, the newborn. Radiofrequency ultrasound spectrometry (REMS) has proven to be a useful tool in the assessment of bone mineral density (BMD) in pregnant women. Few studies have reported that transmission ultrasound can also be used to assess BMD in newborns. The advantages of this technology in the foetus and newborn are the absence of ionising radiation, ease of use, and, above all, the possibility of performing longitudinal studies from intrauterine to extrauterine life. The use of these technologies already in the intrauterine period could help prevent associated diseases, such as osteoporosis and osteopenia, which are characterised by a reduction in bone mass and degeneration of bone structure and lead to an increased risk of fractures in adulthood with considerable social repercussions for the related direct and indirect costs.

Effects of mixed oil emulsion on short-term clinical outcomes in premature infants: A prospective, multicenter, randomized controlled trial

OBJECTIVE

This study compared the clinical effects of two different lipid emulsions in premature infants with gestational age < 32 weeks (VPI) or birth weight < 1500 g (VLBWI) to provide an evidence-based medicine basis for optimizing intravenous lipid emulsion.

METHODS

This was a prospective multicenter randomized controlled study. A total of 465 VPIs or VLBWIs, admitted to the neonatal intensive care unit of five tertiary hospitals in China from March 1, 2021 to December 31, 2021, were recruited. All subjects were randomly allocated into two groups, namely, medium-chain triglycerides/long-chain triglycerides (MCT/LCT) group (n = 231) and soybean oil, medium-chain triglycerides, olive oil, and fish oil (SMOF) group (n = 234). Clinical features, biochemical indexes, nutrition support therapy, and complications were analyzed and compared between the two groups.

RESULTS

No significant differences were found in perinatal data, hospitalization, parenteral and enteral nutrition support between the two groups (P > 0.05). Compared with the MCT/LCT group, the incidence of neonates with a peak value of total bilirubin (TB) > 5 mg/dL (84/231 [36.4% vs. 60/234 [25.6%]), a peak value of direct bilirubin (DB) ≥ 2 mg/dL (26/231 [11.3% vs. 14/234 [6.0%]), a peak value of alkaline phosphatase (ALP) > 900 IU/L (17/231 [7.4% vs. 7/234 [3.0%]), and a peak value of triglycerides (TG) > 3.4 mmol/L (13/231 [5.6% vs. 4/234[1.7%]]) were lower in the SMOF group (P < 0.05). Univariate analysis showed that in the subgroup analysis of < 28 weeks, the incidence of parenteral nutrition-associated cholestasis (PNAC) and metabolic bone disease of prematurity (MBDP) were lower in the SMOF group (P = 0.043 and 0.029, respectively), whereas no significant differences were present in the incidence of PNAC and MBDP between the two groups at > 28 weeks group (P = 0.177 and 0.991, respectively). Multivariate logistic regression analysis revealed that the incidence of PNAC (aRR: 0.38, 95% confidence interval [CI]: 0.20-0.70, P = 0.002) and MBDP (aRR: 0.12, 95% CI: 0.19-0.81, P = 0.029) in the SMOF group were lower than that in the MCT/LCT group. In addition, no significant differences were recorded in the incidence of patent ductus arteriosus, feeding intolerance, necrotizing enterocolitis (Bell's stage ≥ 2), late-onset sepsis, bronchopulmonary dysplasia, intraventricular hemorrhage, periventricular leukomalacia, retinopathy of prematurity and extrauterine growth retardation between the two groups (P > 0.05).

CONCLUSIONS

The application of mixed oil emulsion in VPI or VLBWI can reduce the risk of plasma TB > 5 mg/dL, DB ≥ 2 mg/dL, ALP > 900 IU/L, and TG > 3.4 mmol/L during hospitalization. SMOF has better lipid tolerance, reduces the incidence of PNAC and MBDP, and exerts more benefits in preterm infants with gestational age < 28 weeks.

Analysis of risk factors for parenteral nutrition-associated cholestasis in preterm infants: a multicenter observational study

BACKGROUND

It is proposed that the development of parenteral nutrition-associated cholestasis (PNAC) was significantly associated with preterm birth, low birth weight, infection, etc.; however, the etiology and pathogenesis of PNAC are not fully understood. Most of the studies examining PNAC-associated risk factors were single-center studies with relatively small sample sizes.

OBJECTIVE

To analyze the risk factors associated with PNAC in preterm infants in China.

METHODS

This is a retrospective multicenter observational study. Clinical data on the effect of multiple oil-fat emulsions (soybean oil-medium chain triglycerides-olive oil-fish oil, SMOF) in preterm infants were collected from a prospective multicenter randomized controlled study. A secondary analysis was performed in which preterm infants were divided into the PNAC group and the non-PNAC group based on the PNAC status.

RESULTS

A total of 465 cases very preterm infants or very low birth weight infants were included in the study in which 81 cases were assigned to the PNAC group and 384 cases were assigned to the non-PNAC group. The PNAC group had a lower mean gestational age, lower mean birth weight, longer duration of invasive and non-invasive mechanical ventilation, a longer duration oxygen support, and longer hospital stay (P < 0.001 for all). The PNAC group had higher respiratory distress syndrome, hemodynamically significant patent ductus arteriosus, necrotizing enterocolitis (NEC) with stage II or higher, surgically treated NEC, late-onset sepsis, metabolic bone disease, and extrauterine growth retardation (EUGR) compared to the non-PNAC group (P < 0.05 for all). In contrast with the non-PNAC group, the PNAC group received a higher maximum dose of amino acids and fat emulsion, more medium/long-chain fatty emulsion, less SMOF, had a longer duration of parenteral nutrition, lower rates of breastfeeding, higher incidence of feeding intolerance (FI), more accumulated days to achieve total enteral nutrition, less accumulated days of total calories up to standard 110 kcal/kg/day and slower velocity of weight growth (P < 0.05 for all). Logistic regression analysis indicated that the maximum dose of amino acids (OR, 5.352; 95% CI, 2.355 to 12.161), EUGR (OR, 2.396; 95% CI, 1.255 to 4.572), FI (OR, 2.581; 95% CI, 1.395 to 4.775), surgically treated NEC (OR, 11.300; 95% CI, 2.127 ~ 60.035), and longer total hospital stay (OR, 1.030; 95% CI, 1.014 to 1.046) were independent risk factors for the development of PNAC. SMOF (OR, 0.358; 95% CI, 0.193 to 0.663) and breastfeeding (OR, 0.297; 95% CI, 0.157 to 0.559) were protective factors for PNAC.

CONCLUSIONS

PNAC can be reduced by optimizing the management of enteral and parenteral nutrition and reducing gastrointestinal comorbidities in preterm infants.

Diagnostic markers of metabolic bone disease of prematurity in preterm infants

Due to the higher birth rate of preterm infants and improvements in their management, metabolic bone disease of prematurity (MBDP) has a high incidence and is attracting attention. However, clear indicators for the early diagnosis of MBDP are lacking. We aimed to explore simple and feasible early warning indicators for diagnosing MBDP. Our study collected case data of premature infants from two medical centers in Chongqing from January 2020 to February 2022. According to the inclusion and exclusion criteria, data from 136 cases were collected. The correlation between 14 variables in each case and the occurrence of MBDP was analyzed. According to area under the receiver operating characteristic curve (AUROC) analysis, the best cutoff value for each variable was determined. Potential predictors were selected, and Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis was used to establish the association of two models with MBDP, whose results were used to develop a diagnostic nomogram. Furthermore, a model decision curve was analyzed. Four predictors were selected from 14 clinical variables by LASSO regression, and Model I was established, including the following characteristics: height (>36 cm), head circumference (≤29.49 cm), total serum calcium (Ca) (>2.13 mmol/L), and alkaline phosphatase (ALP) (>344 U/L) levels. A single predictor, the ALP level (>344 U/L), was used to establish Model II. The AUROC values of the two models were 0.959 for Model I and 0.929 for Model II. In conclusion, in this study, two diagnostic models of MBDP were developed using four combinations of predictors and ALP as a single predictor. Both models showed good sensitivity and specificity for the early diagnosis of metabolic bone disease (MBD), and an ALP level of 344 U/L was defined as a simple and effective diagnostic threshold. In future studies, using larger samples, diagnostic threshold values of ALP for premature infants of different ages should be established, and internal and external validations are needed to improve the adaptability of the current model.

Bone mineral content for preterm neonates treated with caffeine using dual energy X-ray absorptiometry: An observational study

BACKGROUND

Prematurity is associated with lots of comorbidities. Premature neonates also have lower bone mineral content (BMC) compared to term neonates. Apnea of prematurity is a common complication and caffeine citrate is widely used for its prevention and treatment. Caffeine also affects creatinine clearance, urine flow rate and releases calcium from its storage sites.

OBJECTIVES

The primary objective was to assess BMC in preterm neonates treated with caffeine using dual energy X-ray absorptiometry (DEXA). Secondary objectives were to determine whether caffeine therapy is associated with increased incidence of nephrocalcinosis or bone fracture.

METHODS

Prospective observational study on 42 preterm neonates, 34 weeks' gestation or less; 22 of them received intravenous caffeine (caffeine group) and 20 did not (control group). Serum levels of calcium, phosphorus, alkaline phosphatase, magnesium, sodium, potassium, and creatinine, abdominal ultrasonography, and DEXA scan were done for all included neonates.

RESULTS

BMC showed significant lower levels in the caffeine compared to control group (p = 0.017). Additionally, BMC was significantly lower in neonates who received caffeine for more than 14 days compared to those who received it for 14 days or less(p = 0.04). BMC showed significant positive correlation to birth weight, gestational age, serum P and significant negative correlation to serum ALP. Caffeine therapy duration was negatively correlated to BMC (r = -0.370, p = 0.000) and positively correlated to serum ALP levels (r = 0.667, p = 0.001). None of the neonates had nephrocalcinosis.

CONCLUSIONS

Caffeine administration for more than 14 days in preterm neonates may be associated with lower BMC but not nephrocalcinosis or bone fracture.

Effect of early initiation of enteral nutrition on short-term clinical outcomes of very premature infants: A national multicenter cohort study in China

OBJECTIVES

The management of enteral nutrition in very preterm infants (VPIs) is still controversial, and there is no consensus on the optimal time point after birth at which enteral nutrition can be started. The aim of this study was to investigate the effect of early initiation of enteral nutrition on the short-term clinical outcomes of VPIs.

METHODS

Data of infants (n = 2514) born before 32 wk of gestation were collected from 28 hospitals located in seven different regions of China. Based on whether enteral feeding was initiated within or after 24 h since birth, the infants were divided into an early initiation of enteral feeding (EIEF) group and a delayed initiation of enteral feeding (DIEF) group.

RESULTS

Compared with the DIEF group, the EIEF group was more likely to tolerate enteral nutrition and had less need for parenteral nutrition (all P < 0.05). The EIEF group was associated with lower incidence rates of feeding intolerance, extrauterine growth restriction (EUGR), and late-onset sepsis (LOS) (all P < 0.05). There was no significant difference in the incidence of necrotizing enterocolitis (NEC) (Bell stage ≥2) between the two groups (P = 0.118). The multivariate logistic regression analysis revealed that EIEF was a protective factor against EUGR (odds ratio [OR], 0.621; 95% confidence interval [CI], 0.544-0.735; P < 0.001), feeding intolerance (OR, 0.658; 95% CI, 0.554-0.782; P < 0.001), and LOS (OR, 0.706; 95% CI, 0.550-0.906; P = 0.006).

CONCLUSIONS

Early initiation of enteral feeding was associated with less frequency of feeding intolerance, EUGR, and LOS, and it may shorten the time to reach total enteral feeding without increasing the risk of NEC.

Early elevated alkaline phosphatase as a surrogate biomarker of ongoing metabolic bone disease of prematurity

Very low birth weight (VLBW) neonates present a high risk of metabolic bone disease (MBD). Our main objective was to determine the easiest way to make an early diagnosis of this disease by identifying surrogate biomarkers before any radiological signs occurred. We conducted in our NICU a 6-month observational prospective study, with inclusion of all singleton VLBW neonates. We collected clinical and biological data, and nutritional intakes during hospitalization. We defined biological MBD (bMBD) as alkaline phosphatase (ALP) levels superior to 600 UI/L at day of life 30 (DOL30) and performed a case-control analysis. Nine out of 30 patients (30%) exhibited bMBD. All have extremely low birth weight and were significantly younger in gestational age (GA) and smaller at birth. There was no statistically significant difference in nutritional intake between bMBD and control groups. In the bMBD group, phosphatemia was lower since DOL3. ALP was already significantly higher at DOL15, and way beyond normal range.

CONCLUSIONS

Our results showed that even the strict respect of nutritional guidelines cannot completely prevent bMBD in high-risk patients and suggest that an early screening from DOL15, with ALP levels greater than 500 UI/L, could be sufficient for detection of upcoming MBD.

WHAT IS KNOWN

• Metabolic bone disease of prematurity (MBD) definition is not consensual, but biological changes appear earlier than radiological signs of rickets. • MBD management relies on biological evidence. Treatment is based on phosphate and/or calcium and calcitriol supplementation.

WHAT IS NEW

• Studying phosphocalcic biological assessment in very low birth weight neonates, we showed respect of nutritional guidelines could not protect from biological MBD. • Increase in alkaline phosphatase (ALP), about 500 UI/l at day of life 15, could be a biomarker of MBD with no need of X-ray evaluation and sufficient to begin a treatment to prevent osteopenia.

Sodium Glycerophosphate Use in Parenteral Nutrition Improves Mineral Metabolism in Extremely Low Birth Weight Infants

OBJECTIVE

To evaluate the clinical effect of sodium glycerophosphate (NaGP) in parenteral nutrition solutions on mineral metabolism in extremely low birth weight (ELBW) infants.

STUDY DESIGN

NaGP was introduced for use in place of potassium phosphate (K₃PO₄) in January 2018; this retrospective cohort study included 95 ELBW infants treated with K₃PO₄ between January 2015 and December 2017 and 77 infants treated with NaGP between August 2018 and January 2021. Mineral intake over the first 14 days; changes in serum calcium, phosphorus, sodium, and alkaline phosphatase (ALP) levels over the first 1-3 months; and the rates of electrolyte imbalance and clinical morbidity were compared. High-risk infants who had nil per os (NPO) status for >14 days and prolonged parenteral nutrition exposure were further analyzed as a subgroup.

RESULTS

The use of NaGP instead of K₃PO₄ significantly increased Ca and P intake, but intakes remained below the recommended range (Ca, 64-140 mg/kg/day; P, 50-108 mg/kg/day). Compared with levels in the K₃PO₄ group, the NaGP group had significantly higher serum Ca and P levels after day 14 and lower ALP levels after day 56. In the subgroup analysis, the NaGP group had significantly lower incidences of hypophosphatemia, hyponatremia, bronchopulmonary dysplasia, and ALP >500 IU/L.

CONCLUSIONS

Although the administration of NaGP instead of K₃PO₄ in parenteral nutrition regimens still did not provide adequate Ca and P intake for ELBW infants, higher intake significantly improved serum Ca and P levels, especially in ELBW infants with prolonged parenteral nutrition exposure.

Incidence, Risk Factors and Prediction of Secondary Hyperparathyroidism in Preterm Neonates under 32 Weeks’ Gestational Age

In preterm newborns, secondary hyperparathyroidism (HPTH) is an underdiagnosed and undertreated entity. Its detection in the context of metabolic bone mineral disease (MBD) screening programs may be important to guide nutritional treatment. We designed a retrospective cohort study to determine the incidence of HPTH in very premature infants. As secondary objectives, we studied the risk factors, morbidities, and biochemical alterations associated with HPTH. A total of 154 preterm newborns ≤32 weeks gestational age (GA) were included. Of these, 40.3% (n = 62) presented with HPTH. In the multivariate analysis, independent risk factors for HPTH were cesarean section (OR: 4.00; 95% CI: 1.59–10.06), oxygen during resuscitation (OR: 3.43; 95% CI: 1.09–10.81), invasive mechanical ventilation (OR: 3.56; 95% CI: 1.63–7.77) and anemia requiring transfusion (OR: 2.37; 95% CI: 1.01–5.57). Among the analytical variables, serum calcium (OR: 0.53; 95% CI: 0.29–0.97), serum phosphate (OR: 2.01; 95% CI: 1.39–2.92), vitamin D (OR: 0.96; 95% CI: 0.93–1), and the calcium/creatinine ratio in urine (OR: 0.05; 95% CI: 0.01–0.28) were independently associated with HPTH. The simplified predictive model included GA and calcium/creatinine ratio in urine and demonstrated an AUC of 0.828. We concluded that HPTH is a frequent entity among very premature infants and that further studies are required to determine the role of HPTH in MBD and the clinical applicability of prediction models.

Effectiveness and safety of early versus late caffeine therapy in managing apnoea of prematurity among preterm infants: a retrospective cohort study

BACKGROUND

Early administration of intravenous (IV) caffeine (initiation within 2 days of life) is an effective treatment strategy for the management of apnoea of prematurity among infants. However, the safety and effectiveness of early administration of oral caffeine treatment is not be fully established.

AIM

We aimed to compare the effectiveness and safety of early versus late caffeine therapy on preterm infants' clinical outcomes.

METHOD

A retrospective matched cohort study was conducted using data of patients admitted to neonatal intensive care units of two tertiary care hospitals between January 2016 and December 2018. The clinical outcomes and mortality risk between early caffeine (initiation within 2 days of life) and late caffeine (initiation ≥ 3 days of life) were compared.

RESULTS

Ninety-five pairs matched based on gestational age were included in the study. Compared to late initiation, preterm infants with early caffeine therapy had: a shorter duration of non-invasive mechanical ventilation (median 5 days vs. 12 days; p < 0.001); shorter length of hospital stay (median 26 days vs. 44 days; p  < 0.001); shorter duration to achieve full enteral feeding (median 5 days vs. 11 days; p < 0.001); and lower frequency of bronchopulmonary dysplasia (BPD) (4.5% vs. 12.9%; p = 0.045). They also had a reduced risk of osteopenia of prematurity (OP) (OR 0.209; 95% CI 0.085-0.509; p = 0.001).

CONCLUSION

Early oral caffeine therapy can potentially improve respiratory outcomes among infants with apnoea of prematurity. However, an increase in mortality associated with early caffeine therapy requires further investigation.

Relationship of caffeine regimen with osteopenia of prematurity in preterm neonates: a cohort retrospective study

BACKGROUND

Caffeine is a routinely prescribed pharmacological active compound in neonatal intensive care units (NICU) for treating apnea of prematurity (AOP), which also decreases the risk of bronchopulmonary dysplasia and cerebral palsy in neonates. Caffeine-induced excessive calcium loss can promote the development of metabolic bone disease (MBD) in preterm neonates. This study aimed to evaluate the effect of the caffeine regimen on the development of osteopenia of prematurity (OOP), using serum alkaline phosphatase (serum-ALP) concentrations as a surrogate marker at the 4^th week of life.

METHODS

This retrospective cohort study was conducted including neonates of < 32 weeks gestational age (GA) and birth weight < 1500 g, admitted to NICU from April-2017 to December-2018 and received caffeine therapy till 28 days of life for AOP. Based on serum-ALP levels, formed the high and low-ALP groups. Neonatal characteristics, caffeine regimen, risk factors for OOP, including duration of parenteral nutrition (PN), exposure to medicines associated with MBD, and intake of essential vitamins and minerals, were compared in both groups. Predictors of OOP were analyzed through logistic regression.

RESULTS

From the total of 268 participants, 52 (19%) developed OOP, mostly female (61.5%). In the high ALP group, the serum-ALP levels were significantly higher than in the low-ALP group (725.0 ± 143.8 vs 273.6 ± 55.0 units/L, p < 0.001). The high-ALP group received significantly (p < 0.001) higher daily and cumulative caffeine doses and were associated with a higher likelihood of developing OOP in this study cohort [cumulative dose (mg) (AOR = 1.082 95% CI 1.011 to 1.157) and daily dose (mg/kg/day) (AOR = 2.892 95% CI 1.392 to 6.007)]. Smaller GA was found directly related to OOP. Among the other medical risk factors, phosphorus intake was significantly low in the high-ALP group. No, significant relationship between duration of PN and use of steroids and diuretics, and intake of vitamins and minerals were identified.

CONCLUSION

The daily and cumulative doses of caffeine and smaller GA are associated with the development of OOP in this study cohort. Clinical randomized control studies are needed to validate the outcomes and determine the range of safest and most effective caffeine doses for treating AOP in preterm neonates.

Incidence of extrauterine growth retardation and its risk factors in very preterm infants during hospitalization: a multicenter prospective study

OBJECTIVES

To investigate the incidence of extrauterine growth retardation (EUGR) and its risk factors in very preterm infants (VPIs) during hospitalization in China.

METHODS

A prospective multicenter study was performed on the medical data of 2 514 VPIs who were hospitalized in the department of neonatology in 28 hospitals from 7 areas of China between September 2019 and December 2020. According to the presence or absence of EUGR based on the evaluation of body weight at the corrected gestational age of 36 weeks or at discharge, the VPIs were classified to two groups: EUGR group (n=1 189) and non-EUGR (n=1 325). The clinical features were compared between the two groups, and the incidence of EUGR and risk factors for EUGR were examined.

RESULTS

The incidence of EUGR was 47.30% (1 189/2 514) evaluated by weight. The multivariate logistic regression analysis showed that higher weight growth velocity after regaining birth weight and higher cumulative calorie intake during the first week of hospitalization were protective factors against EUGR (P<0.05), while small-for-gestational-age birth, prolonged time to the initiation of total enteral feeding, prolonged cumulative fasting time, lower breast milk intake before starting human milk fortifiers, prolonged time to the initiation of full fortified feeding, and moderate-to-severe bronchopulmonary dysplasia were risk factors for EUGR (P<0.05).

CONCLUSIONS

It is crucial to reduce the incidence of EUGR by achieving total enteral feeding as early as possible, strengthening breastfeeding, increasing calorie intake in the first week after birth, improving the velocity of weight gain, and preventing moderate-severe bronchopulmonary dysplasia in VPIs.

Comparison of two methods measuring serum alkaline phosphatase in neonates

BACKGROUND

Serum alkaline phosphatase (ALP) is a useful bone turnover marker to diagnose metabolic bone disease in preterm infants. In Japan, serum ALP levels were generally measured using the Japan Society of Clinical Chemistry (JSCC) method. It is problematic that ALP levels measured using the JSCC method tend to be higher in people with blood types B and O regardless of the disease. For international standardization, since 2020, the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) method has been used as a reference method for ALP measurement instead of the JSCC method. However, no report has investigated the correlation between these two methods in neonates. We therefore aimed to compare the JSCC and IFCC methods and demonstrate a conversion formula in neonates.

METHODS

In this retrospective study, we used a total of 402 samples in 49 preterm and 38 term infants. Serum ALP levels were measured using the JSCC and IFCC methods.

RESULTS

Alkaline phosphatase measured using the JSCC method strongly correlated with that measured using the IFCC method in all blood types in preterm and term infants (P < 0.01 for all).

CONCLUSIONS

We found that the serum ALP levels measured using the IFCC method could be calculated as 0.34 times the ALP levels measured using the JSCC method in preterm and term infants with any blood type: ALP levels (IFCC method) = 0.34 × ALP levels (JSCC method).

Risk factors for metabolic bone disease among preterm infants less than 32 weeks gestation with Bronchopulmonary dysplasia

Background

Bronchopulmonary dysplasia (BPD) infants present an increased incidence of metabolic bone disease (MBD), but it is unknown which factors contribute to this. The aim of this study was to determine the risk factors for developing MBD in BPD infants.

Methods

A retrospective review of the medical records of BPD infants admitted to the Neonatal intensive care unit at Zhangzhou Hospital between Jun 2016 and May 2020 was performed. BPD infants with MBD were identified, two contemporaneous without MBD matched by gestational age and gender were randomly selected as controls for each case of MBD. The association between putative risk factors and MBD was estimated with ORs and 95% CIs. A P-value threshold ≤0.2 was used in univariate analysis for inclusion into a multivariate (adjusted) model with a P-value of < 0.05 as statistically significant.

Results

A total of 156 BPD infants were enrolled with 52 cases of MBD and 104 controls. Fetal growth restriction (OR 6.00, 95% CI, 1.81–19.84), extremely low birth weight (OR 3.10, 95% CI, 1.07–8.94), feeding volume < 80 mL/kg/d at the end of the 4th week after birth (OR 14.98, 95% CI, 4.04–55.58), cholestasis (OR 4.44, 95% CI, 1.59–12.40), late onset sepsis (OR 3.95, 95% CI, 1.12–13.98) and prolonged (> 2 weeks) diuretics application (OR 5.45, 95% CI, 1.25–23.84) were found to be statistically significant risk factors for MBD in BPD infants.

Conclusion

In BPD infants of homogeneous gestational age, fetal growth restriction, extremely low birth weight, feeding volume < 80 mL/kg/d at the end of the 4th week after birth, cholestasis and late onset sepsis are significant risk factors for MBD. These findings provide potential predictive factors for MBD in BPD infants and warrant prospective validation.

[Epidemiology and risk factors for bronchopulmonary dysplasia in prematures infants born at or less than 32 weeks of gestation]

OBJECTIVES

To describe risk factors of bronchopulmonary dysplasia in very preterm infants in the first weeks of life.

MATERIAL AND METHODS

Retrospective cohort study of preterm infants ≤ 32 weeks of gestational age and birth weight ≤ 1500 g. A multivariate logistic regression analysis was performed to identify independent risk factors for bronchopulmonary dysplasia in the first weeks of life.

RESULTS

A total of 202 newborns were included in the study (mean gestational age 29.5 ± 2.1 weeks), 61.4% never received invasive mechanical ventilation. The incidence of bronchopulmonary dysplasia was 28.7%, and 10.4% of the patients were diagnosed with moderate-severe bronchopulmonary dysplasia. Bronchopulmonary dysplasia was independently associated with gestational age at birth (p < 0.001; OR = 0.44 [95% CI = 0.30-0.65]), the need for mechanical ventilation on the first day of life (p = 0.001; OR = 8.13 [95% CI = 2.41-27.42]), nosocomial sepsis (p < 0.001; OR = 9.51 [95% CI = 2.99-30.28]) and FiO2 on day 14 (p < 0.001; OR = 1.39 [95% CI = 1.16-1.66]). Receiving mechanical ventilation at the first day of life (p = 0.008; OR = 5.39 [95% CI = 1.54-18.89]) and at the third day of life (p = 0.001; OR = 9.99 [95% CI = 2.47-40.44]) and nosocomial sepsis (p = 0.001; OR = 9.87 [95% CI = 2.58-37.80]) were independent risk factors for moderate-severe bronchopulmonary dysplasia.

CONCLUSIONS

Gestational age at birth, mechanical ventilation in the first days of life and nosocomial sepsis are early risk factors for bronchopulmonary dysplasia. The analysis of simple and objective clinical data, allows us to select a group of patients at high risk of bronchopulmonary dysplasia in whom it could be justified to act more aggressively, and shows areas for improvement to prevent its development or reduce its severity.

Screening of Serum Alkaline Phosphatase and Phosphate Helps Early Detection of Metabolic Bone Disease in Extremely Low Birth Weight Infants

Background: Extremely low birth weight (ELBW, <1,000 g) infants have a high risk of metabolic bone disease (MBD). Because of the late appearance of radiological signs, diagnosis of MBD in ELBW infants might be delayed, and its prevalence underestimated in this group of patients. This study adopted serial screening of serum alkaline phosphatase (ALP) and phosphate (P) of ELBW infants to determine whether such screening is helpful for the early detection of MBD. Materials and Methods: We performed a retrospective study of preterm infants with a gestational age ≤ 31 weeks and birth weight <1,000 g. MBD was absent (ALP ≤500 IU/L), mild (ALP >500 IU/L, P ≥4.5 mg/dL), and severe (ALP >500 IU/L, P <4.5 mg/dL); MBD was divided into early MBD (≤4 weeks after birth) and late MBD (>4 weeks after birth) according to the time of onset. Results: A total of 142 ELBW infants were included, with a median gestational age of 28.1 (26.5-29.7) weeks and a median birth weight of 875 (818-950) g. Seventy-three cases of MBD were diagnosed, and the total prevalence was 51.4% (mild MBD, 10.6%; and severe MBD, 40.8%). Male sex, breastfeeding, and sepsis would increase the risk of severe MBD. Most MBD in ELBW infants occurred at 3-4 weeks after birth. Sixty-two percent (45/73) of infants were diagnosed as having early MBD, which are diagnosed earlier than late MBD [24 (21-26) vs. 39 (36-41), t = -7.161; P < 0.001]. Male sex [odds ratio (OR), 2.86; 95% confidence interval (CI), 1.07-7.64; P = 0.036], initial high ALP levels (OR, 1.02; 95% CI, 1.01-1.03; P < 0.001), and breastfeeding (OR, 5.97; 95% CI, 1.01-25.12; P = 0.049) are independent risk factors for the development of early MBD. Conclusion: The risk of MBD among ELBW infants is very high. Most cases occurred early and were severe. Male sex, initial high ALP levels, and breastfeeding are closely related to the increased risk of early MBD. Serial screening of serum ALP and P helps early detection of MBD; it is recommended to start biochemical screening for ELBW infants 2 weeks after birth and monitor their biochemical markers weekly.

Endocrine Diseases of Newborn: Epidemiology, Pathogenesis, Therapeutic Options, and Outcome "Current Insights Into Disorders of Calcium and Phosphate in the Newborn"

The physiology and regulation of bone minerals in the fetus and the newborn is significantly different from children and adults. The bone minerals calcium, phosphate and magnesium are all maintained at higher concentrations in utero to achieve adequate bone accretion. This is an integral component of normal fetal development which facilitates safe neonatal transition to post-natal life. When deciphering the cause of bone mineral disorders in newborns, the potential differential diagnosis list is broad and complex, including several extremely rare conditions. Also, significant discoveries including new embryological molecular genetic transcription factors, the role of active placental mineral transport, and hormone regulation factors have changed the understanding of calcium and phosphate homeostasis in the fetus and the newborn. This article will guide clinicians through an updated review of calcium and phosphate physiology, then review specific conditions pertinent to successful neonatal care. Furthermore, with the advancement of increasingly rapid molecular genetic testing, genomics will continue to play a greater role in this area of fetal diagnostics and prognostication.

Analysis of the Clinical Features of Intrauterine Ureaplasma urealyticum Infection in Preterm Infants: A Case-Control Study

Objective: To analyze the clinical characteristics of intrauterine Ureaplasma urealyticum (UU) infection in premature infants. Method: In this single-center retrospective case-control study, 291 preterm infants born in our hospital and hospitalized in our department and gestational age no more than 32 weeks, birth weight no more than 2000 g were included from January 2019 to January 2021. Lower respiratory tract secretion, gastric fluid and urine were collected for UU RNA detection within 48 h after birth. Intrauterine UU infection is defined by at least one positive UU-PCR test of secreta or excreta of preterm infants after birth. The UU infection group included 86 preterm infants and the non-UU infection group included 205 preterm infants. We compared their clinical features, hemogram changes and disease outcomes using statistical analyses. Results: The clinical characteristics of premature infants such as the duration of oxygen use and ventilator use in hospital were significantly prolonged in the UU infection group (P < 0.05). The levels of leukocytes, platelet and procalcitonin in the UU infection group were significantly higher than in the non-UU infection group (P < 0.05). In terms of preterm complications, only the incidences of bronchopulmonary dysplasia, retinopathy of prematurity and metabolic bone disease in premature infants in the UU infection group were significantly higher than those in the non-UU infection group (P < 0.05). The mode of delivery, maternal premature rupture of membranes, and postnatal leukocyte level were independent risk factors for UU infection, while gestational hypertension was a protective factor for UU infection. The level of leukocytes in postnatal hemogram of premature infants could be used as a diagnostic index of UU infection, but the diagnostic accuracy was poor. Conclusion: In our study, UU infection can increase the incidence of bronchopulmonary dysplasia, retinopathy of prematurity and metabolic bone disease in preterm infants, but have no effect on the incidence of necrotizing enterocolitis, intracranial hemorrhage, white matter damage and other diseases in preterm infants. For high-risk premature infants, UU should be detected as soon as possible after birth, early intervention and drug treatment necessarily can improve the prognosis as much as possible.

Modified Serum ALP Values and Timing of Apparition of Knee Epiphyseal Ossification Centers in Preterm Infants with Cholestasis and Risk of Concomitant Metabolic Bone Disease of Prematurity

The usefulness of serum alkaline phosphatase (ALP) and phosphorous in screening and monitoring of metabolic bone disease of prematurity (MBDP) still has some limitations, especially in preterm infants with concomitant conditions such as cholestasis. We aimed to assess a modification of serum ALP (M-ALP) as a biomarker for MBDP in preterm infants, and the use of ultrasound monitoring for the apparition of knee ossification centers as marker of bone mineralization. Biochemical and clinical registers were taken from 94 preterm newborns <32 weeks. A significant correlation existed between serum ALP and direct bilirubin (DB), expressed by the regression equation: M-ALP (IU/L) = 302.1 + 96.9 (DB (mg/dL)). The ratio ALP/M-ALP > 1 was demonstrated to be more specific (87.5%) in the diagnosis of MBDP than the cut-off value of serum ALP > 500 IU/L (62.5%). ALP/M-ALP > 1 showed 100% sensitivity and specificity for the diagnosis of MBDP, and a good correlation with specific bone ALP (B-ALP). Patients with the knee nucleus by post-menstrual week 37 had lower B-ALP compared to patients with no nucleus, and no patients with MBDP presented the nucleus by the 40th week. In the absence of reliable specific B-ALP, reinterpreting serum ALP values by M-ALP plus monitoring of knee ossification centers contribute to better management of MBDP in preterm infants with cholestasis.

Metabolic Bone Disease of Prematurity: Risk Factors and Associated Short-Term Outcomes

Despite the importance of early recognition of metabolic bone disease (MBD) of prematurity, there is still significant variability in screening practices across institutions. We conducted an observational study of infants born at ≤32 weeks of gestation with a birth weight of ≤1500 g (n = 218) to identify clinical factors associated with biochemical indicators of MBD. Bone mineral status was assessed by measuring alkaline phosphatase and phosphate levels between weeks 3 and 5 of life. Two comparisons were performed after classifying infants as either MBD (cases) or non-MBD (controls), and as either high or low risk for MBD, as determined based on the results of MBD screening. In total, 27 infants (12.3%) were classified as cases and 96 (44%) as high-risk. Compared with controls, MBD infants had a significantly lower gestational age and birth weight, and a longer duration of parenteral nutrition and hospital stay. Respiratory outcomes were significantly poorer in high- versus low-risk infants. Multivariate logistic regression showed that birth weight was the only independent risk factor for MBD (odds ratio [OR]/100 g, 0.811; confidence interval [CI95%], 0.656-0.992; p = 0.045) and that birth weight (OR/100 g, 0.853; CI95%, 0.731-0.991; p = 0.039) and red blood cell transfusion (OR, 2.661; CI95%, 1.308-5.467; p = 0.007) were independent risk factors for high risk of MBD. Our findings provide evidence of risk factors for MBD that could help clinicians to individualize perinatal management. The association of red blood cell transfusion with MBD is a novel finding that may be related to iron overload and that merits further study.

Appropriate Phosphorus Intake by Parenteral Nutrition Prevents Metabolic Bone Disease of Prematurity in Extremely Low-Birth-Weight Infants

BACKGROUND

Metabolic bone disease (MBD) is a common disorder in extremely low-birth-weight (ELBW) infants. However, no studies have investigated whether high-dose calcium (Ca) and phosphorus (P) supplementation by parenteral nutrition (PN) prevents MBD in ELBW infants. This study aimed to identify the effect of PN on MBD in ELBW infants.

METHODS

We retrospectively analyzed ELBW infants who were admitted between April 2011 and March 2017. ELBW infants were divided into the low-P group (n = 22) and the high-P group (n = 26) according to the dose of parenteral P supply. Biochemical and radiological markers of MBD and treatments were analyzed.

RESULTS

Mean daily parenteral intake of Ca and P in the first week was significantly higher in the high-P group than in the low-P group (both P ≤ .001). Serum alkaline phosphatase (ALP) levels were significantly higher in the low-P group than in the high-P group in the first month. ELBW infants in the low-P group received alfacalcidol much more frequently than those in the high-P group. There was a trend of a higher rate of x-ray changes in the low-P group than in the high-P group. No infants developed bone fractures.

CONCLUSION

Appropriate P intake by PN is required to ensure high Ca intake, reduce ALP levels in the first month, and prevent MBD from hyperparathyroidism and does not worsen x-ray findings in ELBW infants.

Effect on metabolic bone disease markers in the neonatal intensive care unit with implementation of a practice guideline

OBJECTIVES

To determine the effect of implementing a 2015 policy for the screening, prevention, and management of metabolic bone disease for very low birth weight (VLBW) infants in two Level IV NICUs.

STUDY DESIGN

Retrospective cohort study of VLBW infants in the 2 years prior to (2013-2014) and after (2016-2017) policy implementation.

RESULTS

We identified 316 VLBW infants in 2013-2014 and 292 in 2016-2017 who met study criteria. After policy implementation, vitamin D supplementation began earlier (20.1 ± 15.5 days vs 30.2 ± 20.1 days, p < 0.0005), the percentage of infants with alkaline phosphatase obtained increased (89.7% vs 76.3%, p < 0.0005), while the percentage of infants with alkaline phosphatase >800 IU/L (11.7 vs 4.5%, p = 0.0001) and phosphorous <4 mg/dL (14.2% vs 7.9%, p = 0.014) fell significantly.

CONCLUSIONS

After policy implementation, vitamin D supplementation began significantly earlier and the rate of detecting abnormal biochemical markers of metabolic bone disease decreased significantly.

Do preterm bones still break? Incidence of rib fracture and osteopenia of prematurity in very low birth weight infants

AIM

Extremely premature babies are at risk of osteopenia of prematurity (OOP) as bone mineralisation in utero increases exponentially after 24 weeks gestation. Our aim was to assess the bone health of very low birth weight (VLBW) infants. We wanted to establish the incidences of OOP and rib fracture. We also looked at which biochemical markers best predicted OOP. Bone health in this vulnerable population is an important aspect of management which should not be overlooked.

METHODS

This was an observational study which included all VLBW infants, born in a national maternity hospital, over a 5-year period. All X-rays performed on these infants were reviewed. Data were also collected on biochemical markers associated with bone health. The medical records of infants with rib fractures were reviewed looking for causes of bone fragility.

RESULTS

Of the 609 VLBW infants included in the study, only two cases of definitive rib fractures were found. This represents a rib fracture incidence of 3 per 1000. Thirty-nine percent of VLBW babies showed radiological evidence suggestive of OOP.

CONCLUSION

Our findings show a lower rate of rib fracture in preterm infants compared to previous evidence. We also showed that these fractures were not evident on the final X-ray prior to discharge. This implies that when an ex-preterm infant presents to the emergency department with a rib fracture there should be an even higher suspicion for non-accidental injury than previously thought.

A Combined Ultrasonic Backscatter Parameter for Bone Status Evaluation in Neonates

Metabolic bone disease (MBD) is one of the major complications of prematurity. Ultrasonic backscatter technique has the potential to be a portable and noninvasive method for early diagnosis of MBD. This study firstly applied CAS to neonates, which was defined as a linear combination of the apparent integrated backscatter coefficient (AIB) and spectral centroid shift (SCS). The objective was to evaluate the feasibility of ultrasonic backscatter technique for assessing neonatal bone health using AIB, SCS, and CAS. Ultrasonic backscatter measurements at 3.5 MHz, 5.0 MHz, and 7.5 MHz were performed on a total of 505 newborns within 48 hours after birth. The values of backscatter parameters were calculated and compared among gestational age groups. Correlations between backscatter parameters, gestational age, anthropometric indices, and biochemical markers were analyzed. The optimal predicting models for CAS were determined. The results showed term infants had lower SCS and higher AIB and CAS than preterm infants. Gestational age and anthropometric indices were negatively correlated with SCS (|r| = 0.45 – 0.57, P < 0.001), and positively correlated with AIB (|r| = 0.36 – 0.60, P < 0.001) and CAS (|r| = 0.56 – 0.69, P < 0.001). Biochemical markers yielded weak or nonsignificant correlations with backscatter parameters. CAS had relatively stronger correlations with the neonatal variables than AIB and SCS. At 3.5 MHz and 5.0 MHz, only gestational age (P < 0.001) independently contributed to the measurements of CAS, and could explain up to 40.5% – 44.3% of CAS variation. At 7.5 MHz, the combination of gestational age (P < 0.001), head circumference (P = 0.002), and serum calcium (P = 0.037) explained up to 40.3% of CAS variation. This study suggested ultrasonic backscatter technique was feasible to evaluate neonatal bone status. CAS was a promising parameter to provide more information about bone health than AIB or SCS alone.

The long-term impacts of preterm birth and associated morbidities on bone health in preschool children: a prospective cross-sectional study from Turkey

Objective: To evaluate the impact of preterm birth on bone health in preschool children.Methods: A total of 166 preschool children (aged 7-8 years) born preterm (n = 86, <37-week gestation) and at term (n = 80, ≥37 weeks of gestation) in our hospital were included in this prospective cross-sectional study. Data on antenatal, perinatal, and early postnatal characteristics and maternal obstetric history were obtained from medical records. Bone densitometry data including total bone mineral content (BMC), bone mineral density (BMD; total, lumbar, and femoral), z-scores, and bone loss were collected for each participant.Results: Current height, weight, and BMI values were significantly lower in the preterm group (p < .001). Serum calcium, phosphorus and alkaline phosphatase (ALP) levels did not differ among groups, whereas VitD3 levels were significantly higher in the preterm group (p = .039). The mean total BMC, total BMD, lumbar (L2-L4) BMD, femur BMD, total z-score, and L2-L4 z-score values were significantly lower for the preterm group, whereas the total, lumbar, and femoral bone loss were significantly higher (p < .001), regardless of the severity of prematurity. Intraventricular hemorrhage (IVH) and retinopathy were significantly associated with lower total BMC (p = .004, p = .012, respectively). Fortified breastfeeding was associated with lumbar bone loss (p = .043), and formula feeding was associated with both femur and lumbar bone loss (p = .006, p = .012, respectively).Conclusions: Our findings revealed long-term adverse effects of preterm birth on bone health, with significantly lower anthropometric values (weight, height, and BMI), lower scores for total BMC, BMD (total, lumbar, femoral), and z-scores (total, femur), along with higher bone loss (total, lumbar, femoral) and higher rates of osteopenia and osteoporosis in preschool children born preterm (whether moderate or very preterm) compared with those born at term. Exclusive breastfeeding appears to reduce the likelihood of long-term bone loss in preterm infants.

Screening for Metabolic Bone Disease of prematurity

Metabolic bone disease (MBD) of prematurity remains a significant comorbid condition in preterm, low birth weight infants. As the majority of in utero calcium (Ca) and phosphorus (Phos) accretion occurs during the third trimester, many of these children have inadequate mineral stores and are at risk for deficiencies of Ca and Phos. While fortification of formula has allowed for increased mineral delivery to premature infants, intestinal immaturity prevents optimal absorption. This is compounded by immobilization, delayed establishment of enteral feeds, long term parenteral nutrition and medications that may alter mineral levels. Over time, biochemical changes occur and accompany MBD, with poor bone mineralization during this period increasing the risk for complications such as osteopenia, rickets and fractures. Screening is largely based on risk factors, but despite the 2013 AAP Consensus Statement, there remains significant variation in screening practices across institutions. A combination of laboratory and radiologic testing is often used to diagnose and manage MBD of prematurity, but there exists a lack of consensus on which screening tests and thresholds to use. This is in part related to a lack of normative data and clinical trials for preterm infants, and a result, a lack of evidence-based guidelines on the diagnosis and timing of potential treatment. Biochemical markers, such as serum Phos, alkaline phosphatase (ALP) and parathyroid hormone (PTH), have shown some benefit in the diagnosis of MBD in some studies, but have not always been reproducible. Radiographs may identify different degrees of skeletal changes, but these changes may not be detected until later in MBD development. Other modalities, such as DXA and ultrasound, have also been used, but these may be limited by lack of standards in preterm infants or lack of availability in some centers. Further research, more specifically clinical trials, are needed to determine which combination of tests can detect MBD at its earliest, in order to promote early treatment and prevent short- and long-term complications of MBD.

Ultrasonic Backscatter Difference Measurement of Bone Health in Preterm and Term Newborns

Metabolic bone disease of prematurity remains a significant problem for preterm infants. Quantitative ultrasound (QUS) has potential as a non-invasive tool for assessing bone health of newborns. The aim of this study was to assess bone health in preterm and term newborns using ultrasonic backscatter difference measurement. This study analyzed a total of 493 neonates, including 239 full-term infants (gestational age [GA] >37 wk), 201 preterm I infants (GA: 32-37 wk) and 53 extreme preterm II infants (GA <32 wk). Ultrasonic backscatter measurements were performed on the calcaneus of infants at birth, and the normalized mean of the backscatter difference spectrum (nMBD) was calculated as an ultrasonic index of neonatal bone status. Simple and multiple linear regressions were performed to determine the association of ultrasonic nMBD with GA, anthropometric characteristics and biochemical markers. Statistically significant differences in GA, anthropometric characteristics (birth weight, birth length [BL], birth head circumference and body mass index [BMI]) and biochemical markers (alkaline phosphatase, serum calcium and serum phosphate) were observed among preterm and term infants. The nMBD for term infants (median = 3.72 dB/μs, interquartile range [IR] = 1.95 dB/μs) was significantly higher than that for preterm I infants (median = 1.95 dB/μs, IR = 3.12 dB/μs), which was, in turn, significantly higher than that for preterm II infants (median = 0.19 dB/μs, IR = 3.50 dB/μs). The nMBD yielded moderate correlations (ρ = 0.57-0.62, p < 0.001) with GA and anthropometric characteristics and weak correlations (|ρ| = 0.08-0.21, p < 0.001 or not significant) with biochemical markers. Multivariate regressions revealed that only BL (p = 0.002) and BMI (p = 0.032) yielded significantly independent contributions to the nMBD measurement, and combinations of BL and BMI could explain up to 42% of the variation of nMBD in newborn infants. This study found that ultrasonic backscatter difference measurement might be helpful in bone health evaluation in preterm and term newborns. The utility of ultrasonic backscatter measurement in diagnosis of metabolic bone disease in infants should be investigated further.

Association of Protein and Vitamin D Intake With Biochemical Markers in Premature Osteopenic Infants: A Case-Control Study

Osteopenia in preterm infants (OP) remains an important challenge and is largely dependent on nutritional post-natal intake of factors influencing bone mineralization. We conducted a prospective case-control study to evaluate the importance of protein and vitamin D intake in OP among neonates with birth weight <1,250 g. Simultaneous serum parathyroid hormone (PTH), alkaline phosphatase (ALP), calcium (Ca), phosphorus (P), vitamin D and protein levels were measured during the first six post-natal weeks. At 6 weeks of age, OP was evaluated using wrist radiographs. Comparisons were analyzed using multivariate linear regression, receiver operating characteristic curves, χ2 and Wilcoxon Rank Sum. Of the 26 premature infants enrolled, 13 developed radiographic OP. Daily protein intake (coef = -0.40, p = 0.001) and vitamin D concentrations (21 ± 5.7 ng/ml) were significantly lower in the OP group compared to non-OP subjects. ALP concentration exceeding 619 IU/L, sensitivity of 76.9% and specificity of 75%, was predictive of OP at 6 weeks post-natally. PTH levels were higher at 6 weeks in OP subjects (193 ± 102.5 pg/ml, p < 0.001) compared to non-OP subjects. The findings in this study support the role of vitamin D and protein intake in the development of OP in VLBW infants and inform future practice and research on best practices for OP management.

Metabolic Bone Disease of Prematurity: Diagnosis and Management

Metabolic Bone Disease (MBD) of prematurity is a multifactorial disorder commonly observed in very low birth weight (VLBW, <1,500 g) newborns, with a greater incidence in those extremely low birth weight (ELBW, <1,000 g). MBD is characterized by biochemical and radiological findings related to bone demineralization. Several antenatal and postnatal risk factors have been associated to MBD of prematurity, although the main pathogenetic mechanism is represented by the reduced placental transfer of calcium and phosphate related to preterm birth. The diagnosis of MBD of prematurity requires the assessment of several biochemical markers, radiological, and ultrasonographic findings. However, the best approach is the prevention of the symptomatic disease, based on the screening of subjects exposed to the risks of developing MBD. Regarding the subjects who need to be screened, there is a substantial agreement on the potential risk factors for MBD. On the contrary, different recommendations exist on the diagnosis, management and treatment of this disorder of bone metabolism. This review was aimed at: (1) identifying the subjects at risk for MBD of prematurity; (2) indicating the biochemical findings to take in consideration for the prevention of MBD of prematurity; (3) suggesting practical recommendations on nutritional intake and supplementation in these subjects. We searched for papers which report the current recommendations for biochemical assessment of MBD of prematurity and for its prevention and treatment. The majority of the authors suggest that MBD of prematurity is a disease which tends to normalize overtime, thus it is not mandatory to mimic the rate of mineral fetal accretion through parenteral or enteral supplementation. The optimization of total parenteral nutrition (TPN) and the early achievement of a full enteral feeding are important goals for the prevention and management of MBD of prematurity.

Outcomes of standardised approach to metabolic bone disease of prematurity

AIM

To assess the current protocol of metabolic bone disease (MBD) at three Monash Health neonatal units (Melbourne, Australia).

METHODS

Retrospective audit of 171 infants born at <32 weeks' gestation over 18 months. Mean gestational age was 28.6 ± 2.1 weeks, and birthweight was 1190 ± 374 g. Risk factors of MBD include intra-uterine growth retardation (n = 33, 19.3%), maternal pre-eclampsia (n = 17, 9.9%), necrotising enterocolitis (n = 9, 5.4%) and medications like methylxanthines (94.2%; mean 54.8 days), diuretics (38.6%; mean 49.2 days) and glucocorticoids (5.3%; mean 35 days).

RESULTS

In total, 84.8% infants had an initial MBD screen (mean age 36.3 days), with 45% having repeated monitoring (mean age 71.9 days), and 14.2% had initial alkaline phosphatase levels >500 U/L, decreasing to 10.1% on follow-up. All infants received additional vitamin D supplementation of 400 IU/day, phosphate of 25.1% (n = 43) and calcium of 19.9% (n = 34). Fractures were identified from clinical documentation in 2.9% (n = 5) of infants. Stratifying into phosphate-treated and untreated groups revealed significant differences (P < 0.001) for gestational age and birthweight: 26.7 ± 1.7 weeks/918 ± 272 g for treated versus 29.2 ± 1.9 weeks/1283 ± 359 g for untreated. In the phosphate-treated group, improvement was seen in mean alkaline phosphatase (pre-treatment 467 ± 204 U/L and post-treatment 342 ± 221 U/L, P < 0.01) and mean phosphate levels (1.8 ± 0.4 vs. 2.2 ± 1.0 mmol/L, P < 0.01). Linear growth difference between phosphate-treated (n = 10) and untreated groups (n = 24) was insignificant at >6 months of age (P = 0.13), although this may reflect limited data.

CONCLUSION

Adequate first-line supplementation with vitamin D and phosphate appeared to improve biochemical markers of MBD, but given the observational nature of this study, further longitudinal/prospective studies are required to confirm these findings.

Mineral Homeostasis and Effects on Bone Mineralization in the Preterm Neonate

Most bone formation and mineralization occurs late in gestation. Accretion of adequate minerals is a key element of this process and is often interrupted through preterm birth. In utero, mineral transport is accomplished via active transport across the placenta and does not require fetal hormone input. Postnatal mineral homeostasis requires a balance of actions of parathyroid hormone, calcitonin, and vitamin D on target organs. Preterm birth, asphyxia, acidosis, and prolonged parenteral nutrition increase the risk of mineral imbalance and metabolic bone disease (MBD). Aggressive postnatal nutrition is key to preventing and treating MBD in preterm infants.

Incidence of metabolic bone disease in preterm infants of birth weight <1250 g and in those suffering from bronchopulmonary dysplasia

BACKGROUND & AIMS

Preterm infants are exposed to a higher risk of developing Metabolic Bone Disease (MBD) with an increased bone fragility, a higher fracture risk and a long-term reduced linear growth and childhood height. Monitoring bone growth has become mandatory in neonatology. Several risk factors have been identified among the population of extremely low birth weight infants, but we still do not know which is the real incidence of MBD since its evaluation is not routinely performed worldwide. The aim of this study was to evaluate the incidence of MBD in preterm infants and in those suffering from bronchopulmonary dysplasia (BPD).

METHODS

Prospective evaluation of patients who developed BPD (BPD group) versus infants who did not develop it (no-BPD group). We examined, in preterms <1.250 g, the metacarpus bone transmission time (mc-BTT) at birth, 21 days and 36 weeks of gestational age (GA) together with biochemical markers of bone status.

RESULTS

We included 135 patients, 55 with BPD. BPD patients received less total proteins in the first two weeks and less energy in the first month of life (p = 0.007 and p < 0.001 respectively). BPD patients had a worse growth velocity at two weeks of age (12.36 ± 7.86 vs 16.59 ± 7.05 g/kg/day, p = 0.001). At 21 days, BPD patients had lower phosphatemia (1.65 ± 0.031 mmol/L vs 1.85 ± 0.034 mmol/L, p = 0.007) and higher alkaline phosphatase levels (411.62 ± 135.31 IU/l vs 338.98 ± 102.20 IU/l, p = 0.005). BPD patients had significantly worse mc-BTT at 36 weeks GA (0.45 ± 0.06 vs 0.50 ± 0.08 μsec, p < 0.001) and a higher incidence of MBD (60% vs 34%; p = 0.012).

CONCLUSIONS

BPD infants are a special subset of patients among preterms who receive, in the first month of life, a lower energy intake than patients without BPD. BPD patients have a suboptimal bone growth and a higher incidence of MBD. Monitoring growth, bone status and optimizing nutritional intakes need to be further improved in preterm infants with BPD.

Caffeine is a risk factor for osteopenia of prematurity in preterm infants: a cohort study

Background

Caffeine, the most commonly used medication in Neonatal Intensive Care Units, has calciuric and osteoclastogenic effects.

Methods

To examine the association between the cumulative dose and duration of therapy of caffeine and osteopenia of prematurity, a retrospective cohort study was conducted including premature infants less than 31 weeks and birth weight less than 1500 g. Osteopenia of prematurity was evaluated using chest X-rays on a biweekly basis over 12 weeks of hospitalization.

Results

The cohort included 109 infants. 51% had osteopenia of prematurity and 8% had spontaneous rib fractures. Using the generalized linear mixed model, caffeine dose and duration of caffeine therapy showed a strong association with osteopenia of prematurity. Steroids and vitamin D were also significantly correlated with osteopenia of prematurity while diuretic use did not show a statistically significant effect.

Conclusion

The cumulative dose and duration of therapy of caffeine, as well as steroid are associated with osteopenia of prematurity in this cohort. Future studies are needed to confirm these findings and determine the lowest dose of caffeine needed to treat effectively apnea of prematurity.

Growth and neurodevelopment in very preterm infants receiving a high enteral volume-feeding regimen - a population-based cohort study

AIM

The aim of this study is to evaluate a feeding regimen routinely providing >180 ml/kg/d fortified human milk to very preterm infants and impact on in-hospital growth, osteopenia, and neurodevelopment.

METHOD

Retrospective population-based descriptive study of infants <30-week gestation admitted within 24 h of birth and discharged during the 6-year period 2005-2010. Growth and neurodevelopment was assessed until 2 years corrected age, and cerebral palsy up to 4 years corrected age Results: Ninety-nine infants below 30-week gestation were admitted within 24 h of birth during the 6-year period, of which 84 (85%) survived to discharge. Two infants had surgical necrotizing enterocolitis, both survived to 2 years follow up. Seventy-eight infants (mean 27 weeks) had complete growth data until discharge. Full enteral feeds were tolerated after mean 10 d. Average milk volumes were 193 ml/kg/d from 15 to 42 d of life. Rates of weight below 10th centile were 10% at birth and 14% at discharge. Head circumference Z-scores were stable from birth to discharge. Blood values did not indicate osteopenia. Increasing head circumference Z-scores were associated with improved language development.

CONCLUSIONS

This high enteral feeding volume regimen was associated with low rates of in-hospital growth restriction and good head growth. High enteral volume intake seems safe and may improve nutritional status of very preterm infants.

Bone Mineral Density According to Dual Energy X-ray Absorptiometry is Associated with Serial Serum Alkaline Phosphatase Level in Extremely Low Birth Weight Infants at Discharge

BACKGROUND

To examine bone mineral density in extremely low birth weight infants at discharge and investigate whether serial measurements of serum alkaline phosphatase (ALP) and phosphate can predict bone mineralization.

METHODS

The individuals were 70 preterm infants. Serum calcium, phosphate, and ALP were measured at weekly intervals during admission in extremely low birth weight infants (mean gestational age, 25.3±2.1 weeks; birth weight, 812.8±141.1 g). Bone mineral apparent density (BMAD) of the lumbar spine was prospectively evaluated by dual energy X-ray absorptiometry at discharge (n=70).

RESULTS

BMAD was classified as poor (< 25^th percentile) at < 0.014 g/cm³, fair (25^th-75^th percentile) at < 0.014-0.021 g/cm³, and good (> 75^th percentile) at > 0.021 g/cm³, based on the distribution of BMAD values in infants with noncomplicated courses of prematurity (n=43). In a further multivariate analysis, the number of total parenteral nutrition days, phosphate at 2 postnatal weeks and 3 postnatal weeks, and ALP at 4 postnatal weeks and 5 postnatal weeks had an impact on bone mineral density at the lumbar spine, independent of gestational age and body weight. Peak ALP activities exceeding 650 IU/L revealed low bone mineral density with 80% sensitivity and 64% specificity (AUC, 0.70; p=0.005).

CONCLUSION

Serial measurements of serum ALP and phosphate are associated with decreased bone mineralization by dual energy X-ray absorptiometry at discharge in extremely low birth weight infants.

Neonatal Parenteral Nutrition Containing Calcium Chloride and Sodium Phosphate

Objective. The authors’ objectives were to determine mineral as well as Al intakes for ≤1000 g birth weight (ELBW) infants supported with parenteral nutrition (PN) solutions containing calcium chloride (CaCl) and sodium phosphate (NaPhos). Study design. This study was a prospective cohort study of 32 ELBW infants. Nutrient and Al intakes were recorded based on actual fluid intakes and concentrations of nutrients and Al in PN solutions. Growth velocities and peak alkaline phosphatase (AP) levels during the hospital stay were recorded. Result. Mean (±standard deviation) weight, length, and head circumference gains and AP were 13.7 ± 1.8 g/kg/d, 1.0 ± 0.2 cm/wk, 0.7 ± 0.1 cm/wk, and 636 ± 227 U/L, respectively. Al intake was 0.27 ± 0.07 µmol/kg/d (7.2 ± 1.8 µg/kg/d) in infants receiving PN with low Al content. This study documented average parenteral Ca and P intakes of 1.15 to 1.20 and 1.19 to 1.29 mmol/kg/d, (46-48 and 37-40 mg/kg/d), respectively, with PN fluid intakes of 90 to 100 mL/kg/d. Conclusion. AP and growth in ELBW infants receiving PN solutions containing CaCl are comparable to those reported in the literature for ELBW infants. Ca and P intakes approaching those reported for preterm infants receiving PN containing calcium gluconate can be provided with PN solutions containing CaCl. Fluid restriction is a significant factor limiting mineral intakes. Al intake can be limited to near FDA recommended intakes in PN solutions containing CaCl.

Bone fracture in severe small-for-gestational-age, extremely low birth weight infants: A single-center analysis

INTRODUCTION

Bone fracture is a complication of extremely low birth weight infants (ELBWIs). This study aimed to analyze risk factors for bone fracture in a population of severe small-for-gestational-age (SGA) ELBWIs.

METHODS

We retrospectively studied data from ELBWIs with a birth weight <1000g and <-2 standard deviations (SDs) born at the National Center for Child Health and Development, Japan, from 2013 to 2015. Infants were divided into fracture and control groups. Serum calcium (Ca) and phosphorus (P) levels, perinatal factors, and previously reported risk factors were analyzed.

RESULTS

Of 25 cases of severe SGA ELBWIs, 5 cases of bone fracture were identified. Gestational age was 27.7±2.2, 29.1±2.6weeks (mean difference [MD] -1.4, 95% confidence interval [CI]: -4.0, -1.2, p=0.280), birth weight (BW) 448±105, 673±216g (MD -225, 95% CI: -433, -17, p=0.036) and BW-SD -4.1±0.1, -3.4±0.8 (MD -0.8, 95% CI: -1.5, -0.02, p=0.045) in the fracture and control groups, respectively. Minimums of serum Ca and P were 6.6±1.4, 8.1±0.8mg/dl (MD -1.5, 95% CI: -2.5, -0.6), p=0.003) and 2.3±0.6, 3.5±1.1mg/dl (MD -1.2, 95% CI: -2.2, -0.1, p=0.027) in the fracture and control groups, respectively.

CONCLUSION

Lower BW and BW-SD were possible risk factors for bone fracture. Hypocalcemia and hypophosphatemia may also contribute to the condition.

Total parenteral nutrition for the very low birth weight infant

Preterm infants, especially very low birth weight (VLBW; <1500 g) and extremely low birth weight (ELBW; <1000 g) infants, are susceptible to growth failure in postnatal life if nutritional demands are not met. Poor postnatal growth in preterm infants is associated with adverse neurodevelopmental outcomes during childhood. Early parental nutrition is of paramount importance to provide appropriate protein and energy in VLBW infants when enteral nutrition is not feasible or is suboptimal. An "early and aggressive" approach of parenteral nutrition in preterm infants has been shown to prevent protein catabolism, induce positive nitrogen balance and improve postnatal growth.

The Clinical and Biochemical Predictors of Bone Mass in Preterm Infants

BACKGROUND

Metabolic bone disease of prematurity still occurs in preterm infants, although a significant improvement in neonatal care has been observed in recent decades. Dual-energy X-ray absorptiometry (DXA) is the precise technique for assessing bone mineral content (BMC) in preterm infants, but is not widely available.

AIM

To investigate the clinical and biochemical parameters, including bone metabolism markers as potential predictors of BMC, in preterm infants up to 3 months corrected age (CA).

MATERIALS AND METHODS

Ca-P homeostasis, iPTH, 25-hydroxyvitamin D, osteocalcin, N-terminal propeptide, cross-linked C-telopeptide and amino-terminal pro C-type natriuretic peptide and the DXA scans were prospectively performed in 184 preterm infants (≤ 34 weeks' gestation) between term age and 3 mo CA. Lower bone mass was defined as BMC below or equal to respective median value for the whole study group, rounded to the nearest whole number.

RESULTS

The appropriate quality DXA scans were available for 160 infants (87%) examined at term and for 130 (71%) tested at 3 mo CA. Higher iPTH level was the only independent predictor of lower BMC at term, whereas lower BMC at 3 mo CA was associated both with lower urinary phosphate excretion and higher serum osteocalcin level. ROC analysis showed that iPTH >43.6 pg/mL provided 40% sensitivity and 88% specificity in identification of preterm infants with lower BMC at term. In turn, urinary phosphate excretion (TRP>97% or UP/Cr ≤0.74 mg/mg) and serum osteocalcin >172 ng/mL provided 40% sensitivity and 93% specificity in identification of infants with decreased BMC at 3 mo CA.

CONCLUSION

Serum iPTH might to be a simple predictor of reduced BMC in preterm infants at term age, but urinary phosphate excretion and serum osteocalcin might predict reduced BMC at 3 mo CA. These results represent a promising diagnostic tool based on simple, widely available biochemical measurements for bone mass assessment in preterm infants.