Effects on bone geometry, density, and microarchitecture in the distal radius but not the tibia in women with primary hyperparathyroidism: A case-control study using HR-pQCT.

Patients with primary hyperparathyroidism (PHPT) have continuously elevated parathyroid hormone (PTH) and consequently increased bone turnover with negative effects on cortical (Ct) bone with preservation of trabecular (Tb) bone. High-resolution peripheral quantitative computed tomography (HR-pQCT) is a new technique for in vivo assessment of geometry, volumetric density, and microarchitecture at the radius and tibia. In this study we aimed to evaluate bone status in women with PHPT compared with controls using HR-pQCT. The distal radius and tibia of 54 women--27 patients with PHPT (median age 60, range 44-75 years) and 27 randomly recruited age-matched healthy controls (median age 60, range 44-76 years)--were imaged using HR-pQCT along with areal bone mineral density (aBMD) by dual-energy X-ray absorptiomentry (DXA) of the ultradistal forearm, femoral neck, and spine (L1-L4). Groups were comparable regarding age, height, and weight. In the radius, patients had reduced Ct area (Ct.Ar) (p = .008), Ct thickness (Ct.th) (p = .01) along with reduced total (p = .002), Ct (p = .02), and Tb (p = .02) volumetric density and reduced Tb number (Tb.N) (p = .04) and increased Tb spacing (Tb.sp) (p = .05). Ct porosity did not differ. In the tibia, no differences in HR-pQCT parameters were found. Moreover, patients had lower ultradistal forearm (p = .005), spine (p = .04), and femoral neck (p = 0.04) aBMD compared with controls. In conclusion, a negative bone effect of continuously elevated PTH with alteration of HR-pQCT assessed geometry, volumetric density, and both trabecular and cortical microarchitecture in radius but not tibia was found along with reduced aBMD by DXA at all sites in female patients with PHPT.