title: Parathyroid hormone as a marker for metabolic bone disease of prematurity.
abstract: OBJECTIVE
  To compare parathyroid hormone to alkaline phosphatase as a serologic marker for metabolic bone disease (MBD) in preterm infants.
  
  
  METHODS
  An 18-month prospective observational study in neonates with birth weight < 1250 g. Simultaneous serum parathyroid hormone (PTH), alkaline phosphatase (ALP), calcium (Ca) and phosphorus (P) were measured at scheduled intervals during hospitalization. At 6 weeks of age, MBD was evaluated using knee radiographs. Comparisons were analyzed using multivariate logistic regression, receiver operating characteristic (ROC) curves, χ² and Student t-test.
  
  
  RESULTS
  Fourty-nine infants were included in the study: 7 with severe and 42 with mild MBD. Using ROC curves, at 660 U l⁻¹ ALP had a sensitivity of 29% and specificity of 93% for severe MBD, while a cutoff point of 180 pg ml⁻¹ gave PTH a sensitivity of 71% and specificity of 88%. Infants with severe bone disease had a lower birth weight, 21-day serum P, an increased use of glucocorticoids and caffeine, and more likely to have major neonatal morbidities.
  
  
  CONCLUSIONS
  PTH is an early marker with better sensitivity than ALP in screening for MBD. At 3 weeks chronologic age, a PTH level > 180 mg dl⁻¹ or a P level <4.6 pg ml⁻¹ yielded a sensitivity of 100% and specificity of 94% for severe MBD [corrected].
authors.affiliation: Department of Pediatrics, University of Texas Health Science Center, San Antonio, TX, USA.
authors.forename: A
authors.initials: A
authors.lastname: Moreira
authors.affiliation: Department of Pediatrics, University of Texas Medical Branch, Galveston, TX, USA.
authors.forename: L
authors.initials: L
authors.lastname: Swischuk
authors.affiliation: Department of Pediatrics, University of Texas Medical Branch, Galveston, TX, USA.
authors.forename: M
authors.initials: M
authors.lastname: Malloy
authors.affiliation: Marian University, Fond du Lac, WI, USA.
authors.forename: D
authors.initials: D
authors.lastname: Mudd
authors.affiliation: Department of Pediatrics, University of Texas Health Science Center, San Antonio, TX, USA.
authors.forename: C
authors.initials: C
authors.lastname: Blanco
authors.affiliation: Department of Pediatrics, University of Texas Medical Branch, Galveston, TX, USA.
authors.forename: C
authors.initials: C
authors.lastname: Geary
mesh_terms: D000469:Alkaline Phosphatase / Q000032:analysis / Q000097:blood*; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D001851:Bone Diseases, Metabolic / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007363:Intensive Care Units, Neonatal; D008297:Male; D010281:Parathyroid Hormone / Q000032:analysis / Q000097:blood*; D011446:Prospective Studies; D012372:ROC Curve; D011859:Radiography; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D010281:Parathyroid Hormone; D000469:Alkaline Phosphatase