Abstract Romosozumab is known to markedly increase areal bone mineral density (aBMD) at the lumbar spine and proximal femur assessed by dual-energy X-ray absorptiometry (DXA), however, its effects on peripheral volumetric BMD (vBMD) and bone microarchitecture measured by high-resolution peripheral quantitative computed tomography (HR-pQCT) remain incompletely characterized in postmenopausal women at very high fracture risk. In this single-center, prospective longitudinal observational study, postmenopausal women with primary osteoporosis and a history of fragility fractures received romosozumab for 12 months. DXA (lumbar spine, proximal femur, and radius) and HR-pQCT (distal radius and tibia) were performed at baseline and at 6 and 12 months. Twenty-five patients were enrolled; 22 completed 12 months and were analyzed. Lumbar spine (L1–L4) aBMD increased by 18.0% at 6 months and 24.4% at 12 months (both p0.001), whereas total hip aBMD increased by 4.9% and 7.3%, respectively (p=0.001 and p0.001). In contrast, radius aBMD did not change significantly at either the one-third distal or ultradistal sites. On HR-pQCT, cortical vBMD at distal radius decreased modestly (−1.0% at 6 months, −1.2% at 12 months, p=0.001 and p=0.002), while trabecular thickness increased at 12 months (+2.0%, p=0.001); no other parameters changed significantly at the distal radius. No significant changes in vBMD or bone microarchitecture were observed at the distal tibia. These findings suggest that 12 months of romosozumab treatment resulted in marked increases in central aBMD at the lumbar spine and proximal femur by DXA, while effects on peripheral aBMD, vBMD, and bone microarchitecture at the distal radius and tibia assessed by DXA and HR-pQCT were limited, suggesting site-specific skeletal responses.
Chiba et al. (Wed,) studied this question.