Analysis of Bone Impairment by 3D DXA Hip Measures in Patients With Primary Hyperparathyroidism: A Pilot Study.

CONTEXT: Primary hyperparathyroidism (PHPT) has been related to bone loss. Dual-energy x-ray absorptiometry (DXA) cannot distinguish between trabecular and cortical bone compartments but the recently developed three-dimensional (3D)-DXA software might overcome this issue.

OBJECTIVE

To examine the differences in DXA-derived areal bone mineral density (aBMD) and 3D-DXA parameters at the hip site between patients with PHPT and a healthy control group.

DESIGN

Cross-sectional pilot study.

SETTING

Hospital.

PATIENTS: 80 adults (59.5 ± 9.1 yrs), 40 with PHPT and 40 age- and sex-matched healthy controls.

MEASURES: aBMD (g/cm2) of the femoral neck, trochanter, shaft, and total hip was assessed using DXA. Cortical surface (sBMD, mg/cm2), cortical volumetric BMD (vBMD, mg/cm3), trabecular vBMD (mg/cm3), integral vBMD (mg/cm3) and cortical thickness (mm) was assessed using 3D-DXA software.

RESULTS

Mean-adjusted values showed lower aBMD (7.5%-12.2%, effect size: 0.51-1.01) in the PHPT group compared with the control group (all P < 0.05). 3D-DXA revealed bone impairment (3.7%-8.5%, effect size: 0.47-0.65) in patients with PHPT, mainly in cortical parameters (all P < 0.05). However, differences in trabecular vBMD were not statistically significant (P = 0.055). The 3D mapping showed lower cortical sBMD, cortical vBMD, and cortical thickness at the trochanter and diaphysis in the PHPT group (P < 0.05) compared with the control group. In both groups, the presence of osteopenia or osteoporosis is related to lower cortical bone.

CONCLUSIONS

aBMD and cortical 3D parameters are impaired in patients with PHPT versus healthy controls. The vBMD of the trabecular compartment seems to be affected, although to a lesser extent.