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Daily clinical markers in metabolic bone disease of prematurity
Hiroko Tomotaki1, Seiichi Tomotaki2, Ai Yoshimura1
1Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Insights
Monitoring preterm infants
Area of Science:
- Neonatal Medicine
- Pediatric Endocrinology
- Metabolic Bone Disease
Background:
- Timely monitoring of bone metabolism in infants is crucial for preventing metabolic bone disease of prematurity.
- Management of hyperparathyroidism in infants requires tailored supplementation based on clinical guidelines.
- This study investigated daily clinical markers in infants with hyperparathyroidism.
Purpose of the Study:
- To clarify the characteristics of daily clinical markers in infants with hyperparathyroidism.
- To establish thresholds for assessing bone metabolism in preterm infants.
- To aid in the timely and tailored management of infant hyperparathyroidism.
Main Methods:
- Retrospective, single-center study at Kyoto University Hospital.
- Included infants born at ≤37 weeks gestation with birth weight <2500g.
- Analyzed serum calcium, phosphorus, urinary calcium/creatinine ratio (Ur Ca/Cre), and % tubular reabsorption of phosphorus (%TRP) in relation to elevated intact parathyroid hormone (iPTH >100 pg/mL).
Main Results:
- 194 infants (366 data points) were analyzed.
- Infants with elevated iPTH often had serum calcium <9.8 mg/dL and/or serum phosphorus <6.5 mg/dL.
- Elevated iPTH was also associated with Ur Ca/Cre <0.67 and/or %TRP <94%.
Conclusions:
- Elevated iPTH in preterm infants can occur even when other clinical indicators are within normal pediatric or adult ranges.
- Established cutoff values (Ca: 9.8 mg/dL, P: 6.5 mg/dL, Ur Ca/Cre: 0.67, %TRP: 94%) are useful for assessing infant bone metabolism.
- These findings support timely, individualized management of hyperparathyroidism in preterm infants.
Background:
Monitoring the condition of infants' bone metabolism timely and providing tailor-made appropriate supplementation are important to prevent severe metabolic bone disease of prematurity. This study aimed to clarify the characteristics of daily clinical markers in infants with hyperparathyroidism under management based on the clinical guidelines.
Methods:
A single-center, retrospective study was performed at Kyoto University Hospital. Infants born at ≤37 weeks of gestation with a birth weight <2500 g were enrolled. Serum calcium and phosphorus concentrations, the urinary calcium to creatinine ratio (Ur Ca/Cre), and the percent tubular reabsorption rate of phosphorus (%TRP) were analyzed in relation to elevated serum intact parathyroid hormone (iPTH) concentrations (>100 pg/mL).
Results:
One hundred ninety-four infants (366 data points) were analyzed. Most infants with iPTH concentrations >100 pg/mL had serum calcium concentrations <9.8 mg/dL and/or serum phosphorus concentrations <6.5 mg/dL. Most infants with iPTH concentrations >100 pg/mL had Ur Ca/Cre <0.67 and/or %TRP < 94%.
Conclusion:
In preterm infants, iPTH concentrations can be elevated, even when daily clinical indicators are within the normal range in children or adults. These thresholds of daily clinical indicators may be useful for assessing bone metabolism timely and can help provide tailor-made management.
Impact:
We clarified the characteristics of daily clinical indicators in infants with hyperparathyroidism (iPTH >100 pg/mL) under management based on the clinical guidelines. The cutoff values using the Youden index of serum calcium and phosphorus concentrations, Ur Ca/Cre, and %TRP were 9.8 mg/dL, 6.5 mg/dL, 0.67, and 94%, respectively. Most infants with hyperparathyroidism had serum calcium concentrations <9.8 mg/dL and/or serum phosphorus concentrations <6.5 mg/dL. Most infants with hyperparathyroidism had Ur Ca/Cre <0.67 and/or %TRP < 94%. In preterm infants, iPTH can be elevated, even when daily clinical indicators are within the normal range in children or adults.
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