Serum Bone Alkaline Phosphatase in Assessing Illness Severity of Infected Neonates in the Neonatal Intensive Care Unit

Background: Infections can influence bone metabolism of neonates, which may lead to changes in some bone metabolism biomarkers. The purpose of this study was to determine whether serum bone alkaline phosphatase (BALP), osteocalcin (OC) and beta carboxy-terminal peptide of type I collagen (CTX), as specific biomarkers of bone metabolism, can be used to assess the severity of neonatal infections. Methods: Sixty-three neonates in the NICU were enrolled in this study. The neonates were divided into infected group (n=33) and non-infected group (n=30). The scores for neonatal acute physiology-perinatal extension II (SNAPPE-II) were calculated and interleukin-6 (IL-6), procalcitonin (PCT), BALP, OC and CTX were measured among the neonates with or without infections, and among the infected neonates before and after treatment. Results: The serum BALP levels were lower in the infected group than that in the non-infected group (p<0.01). The serum BALP levels increased markedly in the infected neonates after treatment (p<0.01). The serum BALP levels were also inversely correlated with SNAPPE-II of infected neonates before and after treatment (r=-0.56, p<0.05; r=-0.37, p<0.05, respectively). In infected neonates, the differences between serum BALP levels before and after treatment were inversely correlated with those of IL-6 levels (p<0.05). There were no significant changes in the OC, CTX and PCT levels in the infected or non-infected group before and after treatment. Conclusion: Our data suggest that serum BALP level might be used as a marker for assessing the severity of illness in infected neonates.