IMPE Abstracts

Introduction: This study aimed to evaluate and compare the trabecular bone scores (TBSs) of 35 patients (11 children and 24 adults) with X-linked hypophosphatemic rickets (XLH) confirmed by PHEX mutations and non-XLH subjects from a tertiary center.

Materials and Methods: The areal bone mineral density at the lumbar spine (LS-aBMD) and LS-aBMD Z score were analyzed by dual-energy X-ray absorptiometry (DXA). The bone mineral apparent density (BMAD) and LS-aBMD Z score adjusted for height Z score (LS-aBMD–HAZ) were also calculated. The TBS was determined using TBS iNsight software (Version 2.1. Med-Imaps. Bordeaux, France) based on DXA images from the Hologic QDR 4500 device and represented the mean measurement of vertebrae L1–L4 within the same region of interest used to measure the LS-aBMD.

Results: The XLH patients exhibited a higher mean LS-aBMD Z score, BMAD, and TBS than the non-XLH subjects (P<0.01). When stratified by age, LS-aBMD–HAZ and BMAD were greater in the XLH children than those in their corresponding non-XLH subjects (P<0.01 and P=0.02), and the XLH children trended toward a greater TBS (P=0.06). The XLH adults had a higher LS-aBMD Z score, BMAD, and TBS than the non-XLH subjects (P<0.01). When stratified by metabolic status according to the serum values of bone formation markers, the compensated adult patients had a higher LS-aBMD Z score, BMAD, and TBS than the non-XLH subjects (P<0.01). Although the noncompensated patients had higher LS-aBMD Z score and BMAD results than the non-XLH subjects, there was no statistically significant difference observed in TBS values between those groups (P=0.45).

Conclusion: The higher LS-aBMD Z score, BMAD, and TBS result in the XLH patients compared to non-XLH subjects indicates an increased amount of trabecular bone within the lumbar spine, regardless of the presence of extraskeletal calcifications.