ESPE Abstracts

Background and Aim: Metabolic Bone Disease of Prematurity(MBD) is a condition of reduced bone mineral content(BMC) compared to the expected for gestational age(GA). Preterm birth interrupts the physiological process of calcium(Ca) and phosphorus(P) deposition that occurs mostly in the 3rd-trimester of pregnancy, leading to an inadequate bone mineralization during intrauterine life(IUL). After birth, an insufficient intake of Ca and P carries on this alteration, resulting in overt disease. Despite advances in neonatal intensive care, MBD is still frequent in preterm infants, with an incidence of 16-23% in Very-Low-Birth-Weight(VLBWI, BW<1500g), and 40-60% in Extremely-Low-Birth-Weight(ELBW, BW<1000g) infants. Several risk factors are associated with MBD(e.g. malabsorption, parenteral nutrition(PN), bronchodysplasia(BPD), necrotizing enterocolitis, and chronic medications). The aim of this study was to evaluate incidence of MBD in a cohort of VLBWI and the role of some risk factors.

Material and Methods: VLBWI of a GA≤32weeks were assessed between 3rd-5th weeks of life. Subjects were classified as increased risk(G1) if P≤4.5mg/dl or ALP≥900UI/l, or standard risk(G2) if P≥4.5mg/dl and ALP≤900UI/L. GA, BW, days on PN and invasive ventilation, and occurrence of BPD were evaluated. Differences between G1-G2 were evaluated using t-test for continuous variables and χ2-test for categorical variables. The statistical significance was fixed at 0.05.

Results: We enrolled 238 VLBWI(107male, 52 at increased risk(G1). Mean P(mg/dl) and ALP(UI/L)were 4.2±1.04vs6.15±0.93 in G1 and G2 respectively (P<0.001). G1-subjects have lower GA (28.53±1.99vs29.38±1.94 weeks, P<0.01) and BW(1019.87g±243.57vs 1162.23g±245.16, P<0.001). Moreover, they needed a longer PN support(25.35days±10.51 vs 20.54days±13.55, P<0.05) and invasive ventilation(7.46 days±9.27 vs 3.41days±10.05, P<0.01). G1 presented a higher incidence of BPD(36.5% vs 20.4%, P=0.026). At linear regression analysis, BW and PN resulted as independent predictor of increased risk(P=0.001, P=0.040, respectively). Preventive strategy led to a reduction in NP, LOS and invasive ventilation(930, 1674 and 744 cumulative days respectively).

Conclusions: VLBWI have an increased risk of MBD. Low BW is correlated with alteration in BMC due to an insufficient provision of Ca and P during IUL. Moreover, despite advances in neonatal nutrition and care, is still difficult to guarantee an adequate amount Ca and P in VLBWI. Further studies are needed to explore the pathophysiological mechanisms underlying MBD in order to implement preventive strategies and reduce the incidence of this complication.