Implementation of Parenteral Nutrition Formulations with Increased Calcium and Phosphate Concentrations and Its Impact on Metabolic Bone Disease in Preterm Infants: A Retrospective Single-Centre Study.

Background: Metabolic Bone Disease of Prematurity (MBDP) is common in extremely preterm infants (≤28 weeks gestation). Parenteral nutrition (PN) with higher calcium (Ca) and phosphorus (P) concentration started soon after birth may improve bone health in preterm infants. We compared the effect of two standard PN formulations on the incidence of MBDP and explored the predictive ability of biochemical markers for diagnosing MBDP.

Methods: This retrospective study included eligible preterm infants ≤ 28 weeks gestation. Infants in group 1 (January 2016-December 2017) received PN 1 formulation with lower Ca (1.6 mmol/kg/day) and P concentration (1.4 mmol/kg/day). Infants in group 2 (June 2018-May 2020) received PN 2 formulation with higher Ca (2.3 mmol/kg/day) and P concentration (1.8 mmol/kg/day). We reviewed the biochemical and radiological investigations performed for diagnosing MBDP.

Results: The incidence of MBDP reduced from 82.8% (77/93) in group 1 to 47.3% (27/57) in group 2. Grade 2-3 MBDP reduced significantly from 14% in group 1 to none in group 2 (p < 0.01). Serum phosphate < 1.5 mmol/L had a sensitivity of 79% and specificity of 77%, and alkaline phosphatase > 500 U/L showed a sensitivity of 72% and specificity of 71% for diagnosing radiological MBDP. There was no increase in hypercalcemia, hypophosphatemia or nephrocalcinosis from PN 2 formulation.

Conclusions: A higher Ca and P concentration in PN reduced MBDP and eliminated grade 2-3 MBDP in our cohort without an increase in adverse events. Low serum phosphate and high serum alkaline phosphatase were the best predictors for diagnosing MBDP.