Volumetric Bone Density and Geometry Assessed by Peripheral Quantitative Computed Tomography in Uremic Patients on Maintenance Hemodialysis

Abstract

The aim of this study was to establish, by means of peripheral quantitative computed tomography (pQCT) at the distal radius, the existence of cortical and/or trabecular osteopenia, and to assess the integrity of bone geometry in uremic patients undergoing maintenance hemodialysis. Our results show a clearcut selective reduction in volumetric cortical density, more evident in women (p = -0.0001) than men (p = 0.030), which appears to be independent of age and menopausal status. Trabecular density was not significantly changed in either sex. Cortical density of the patients correlated inversely with age (p = 0.003), duration of dialysis (p = 0.002) and parathyroid hormone (PTH) levels (p = 0.03). Trabecular density correlated only with age. Normally, cortical density is age-dependent and its reduction is accompanied by compensatory geometry changes. Compared with control subjects, in our female patients both cortical area and cortical thickness were reduced (p = 0.02 and 0.008), while cross-sectional area did not change (p = 0.67). Conversely, in the males only cross-sectional area was reduced (p = 0.02). In conclusion, in uremic patients we observed a selective cortical osteopenia, more evident in the female sex, and a sex-specific pattern of geometry impairment, with resultant apparent increased bone fragility in the uremic women. We suggest that the prolonged PTH excess could be responsible, directly and/or interacting with estrogen deficiency.

Fracture risk assessment in patients with chronic kidney disease

“…Three studies have reported on the use of pQCT in patients with stage 5 CKD on hemodialysis [3,54,55], while one study reported on using it in patients with stage 5 CKD on continuous ambulatory peritoneal dialysis [56]. All were cross-sectional and report a preferential decrease in cortical but not trabecular density in line with the hypothesis that bone loss in CKD patients is primarily due to elevated PTH.…”

Alterations of bone microstructure and strength in end-stage renal failure

“…The first studies used instruments with a 350-μm resolution and showed a lower cortical vBMD, but no significant differences in trabecular BMD in ESRD patients [34][35][36] compared with healthy controls. A recent crosssectional study in 52 adults on maintenance hemodialysis demonstrated that reductions in pQCT values of the radius cortical bone were strongly predictive of vertebral and fragility peripheral fractures, but not pQCT trabecular vBMD and DXA aBMD [37].…”

Fractures in patients with CKD—diagnosis, treatment, and prevention: a review by members of the European Calcified Tissue Society and the European Renal Association of Nephrology Dialysis and Transplantation

“…Long-term exposure to high PTH could induce a preferential loss of cortical bone, which could be even more pronounced in female than in male patients with CKD stage 5D. 123 Parathyroidectomy reduces bone turnover and may improve BMD and reduce the long-term risk of fractures in CKD stage 5D patients.…”