431 - Bone Quality Assessment and Growth in Preterm Infants

Poster Number: 431
Publication Number: 431.137

Ariel Tarrell, University of Utah School of Medicine, Salt Lake City, UT, United States; Sabrina Malone Jenkins, University of Utah, Salt Lake City, UT, United States; Matthew Grinsell, University of Utah, Salt lake City, UT, United States; Bradley A. Yoder, University of Utah, Salt Lake City, UT, United States

Background: The diagnosis of metabolic bone disease (MBD) in preterm infants is challenging. The standard for diagnosis is dual energy x-ray absorptiometry (DXA) to measure bone mineral content (BMC). There is evidence for use of quantitative ultrasound (QUS) for bone health assessment via measuring speed of sound (SOS). SOS is a composite measure determined by BMC, elasticity, strength, and microstructure. Each modality offers different insights into bone health status.

Objective: The objective of this study is to evaluate the relationship between BMC by DXA, and SOS by QUS, with growth parameters in preterm infants.

Design/Methods: 41 preterm infants born ≤ 32 weeks or ≤ 1800 grams were included in this prospective observational study secondary analysis. Bone health was assessed by DXA (Hologic) and QUS (Omnisense 8000) at near-term corrected gestational age (CGA). DXA and QUS were obtained within 7 day of each study. Pearson correlations (R2) and linear regression determined the relationship between demographics, growth parameters, and the two modalities.

Results: Infants were born at a mean gestational age 29.8 ± 2.2 weeks and a mean weight of 1315 ± 429 grams. Bone studies were obtained at a mean CGA of 37.7 ± 2.1 weeks. For birth parameters, BMC did not correlate with birth gestational age, weight, or length (R2 = 0.006, 0.071, and 0.040, p > 0.05 respectively). SOS did correlate with birth gestational age (R2 = 0.261, p < 0.05), weight (R2 = 0.090, p = 0.057), and length (R2 = 0.111, p < 0.05). For current parameters, BMC correlated with CGA (R2 = 0.342, p < 0.05), weight (R2 = 0.794, p < 0.05), and length (R2 = 0.739, p < 0.05) at the time of the DXA study. SOS correlated with CGA (R2 = 0.240, p < 0.05), weight (R2 = 0.285, p < 0.05), and length (R2 = 0.142, p < 0.05) at the time of the QUS study. BMC and SOS comparison yielded weak inverse correlation (R2 0.163, p < 0.05).Conclusion(s): SOS, not BMC, correlated with growth parameters at birth. Both SOS and BMC correlated with growth parameters at the time of bone health assessment. SOS and BMC poorly correlate to each other in preterm infants assessed near term CGA. Given these findings, and the availability to perform repeated QUS at the bedside, we speculate that QUS may be a safer alternative and potentially offer more information about bone health status in growing preterm infants compared to BMC. Additional studies are needed to better understand the roles of QUS and DXA in the assessment of preterm infant bone health.