The Use of Tubular Reabsorption of Phosphorus Versus Intact Parathyroid Hormone to Screen for Metabolic Bone Disease of Preterm Infants With Very Low Birthweight or Extremely Low Birthweight

Authors

Kelsey Soppet
Megan Garrido
Ann-Marie Yaroslaski
Rachel Leung
Sarah Laurenzano
Dawn Novak

Document Type

Presentation

Publication Date

4-13-2023

Abstract

Background: Metabolic bone disease (MBD) is a significant comorbidity in preterm infants, occurring in as many as 23% of very low birth weight (VLBW) infants and 55% of extremely low birthweight infants. There is a lack of consensus in diagnostic and screening criteria for MBD, which makes the true incidence of MBD difficult to determine.

Methods: In August 2020, a new protocol was implemented at UNMH using screening labs to calculate tubular reabsorption of phosphorus (TRP) in VLBW preterm infants less than 28 weeks gestational age or considered at risk for MBD. A retrospective chart review was conducted to evaluate if using TRP was effective for identifying MBD. Fifty VLBW preterm infants born from August 2020 to April 2022 were identified. Of these infants, 43 had labs collected, 37 had labs collected to calculate TRP, 13 had TRP that could be calculated, 19 had intact parathyroid hormone (iPTH) collected and 7 had both measurable iPTH and TRP. Alkaline phosphatase was obtained in all infants who had labs collected.

Results: Labs used to calculate TRP were collected in 86% of infants (37/43). These lab values could only be used to calculate TRP in 35% of infants (13/37). Four infants had TRP >95%, and no infants had TRP >95% with phosphorus100 pg/mL (9/19) concerning for MBD. Twenty-six percent of infants had elevated alkaline phosphatase levels concerning for MBD (11/43).

Discussion: Although appropriate labs to calculate TRP were collected in most at-risk infants, our laboratory’s ability to detect serum creatinine less than 0.14 mg/dL and urine creatinine less than 13 mg/dL limited the utility of TRP. Effective screening methods for MBD at our institution should include serum calcium, phosphorus, iPTH and alkaline phosphatase.

Comments

Presentation presented at Pediatric Research Forum

Recommended Citation

Soppet, Kelsey; Megan Garrido; Ann-Marie Yaroslaski; Rachel Leung; Sarah Laurenzano; and Dawn Novak. "The Use of Tubular Reabsorption of Phosphorus Versus Intact Parathyroid Hormone to Screen for Metabolic Bone Disease of Preterm Infants With Very Low Birthweight or Extremely Low Birthweight." (2023). https://digitalrepository.unm.edu/hsc_2023_pediatric_research/19