Metabolic Bone Disease of Prematurity in Very Low Birthweight Infants: Retrospective Observational Study

Abstract

Introduction: Metabolic bone disease of prematurity consists in a decrease of bone matrix mineral content, in comparison with the level expected for gestational age. Screening of this condition is based on serum alkaline phosphatase and phosphate levels. The aim of this study is to evaluate the prevalence of metabolic bone disease of prematurity, to assess the aspects associated with a higher risk of this disease and to describe the growth of newborns with birth weight below 1500 g and metabolic bone disease of prematurity.
Material and Methods: Observational, retrospective, multicenter and descriptive study in three neonatal intensive care units in Portugal, from May 1st 2016 to April 30th 2017. A convenience sample of very low birthweight newborns was obtained. Demographic, clinical, and laboratory variables were described in newborns with and without metabolic bone disease of prematurity.
Results: A total of 53 newborns were included in this study: 30 males, 16 with gestational age ≤ 28 weeks. Five cases of metabolic bone disease of prematurity were diagnosed. In this group, the majority of patients was male and presented a lower gestational age and birth weight, in comparison with the group without metabolic bone disease of prematurity. The average duration of parenteral nutrition was higher in newborns with metabolic bone disease of prematurity and the calcium/phosphate ratio was lower than the recommended values. Growth was similar in both groups. No patient with metabolic bone disease of prematurity underwent physical rehabilitation.
Discussion: The prevalence of metabolic bone disease of prematurity was 9.43%, which is lower than what is described in the literature. However, only 50% of newborns completed the screening according to the recommendations. The main risk factors identified concur with the literature.
Conclusion: Metabolic bone disease of prematurity is a frequent but underdiagnosed comorbidity in very low birthweight newborns. It is essential to screen newborns at risk for this condition, using biochemical markers, as well as structure nutritional interventions and physical stimulation in order to avoid short and long-term consequences of this disease.