Volumetric bone density and geometry assessed by peripheral quantitative computed tomography in uremic patients on maintenance hemodialysis

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 independen t of age and menopausal status. Trabecular density was not significantly ch anged in either sex. Cortical density of the patients correlated inversely with age (p = 0.003), duration of dialysis (p = 0.002) and parathyroid horm one (PTH) levels (p = 0.03). Trabecular density correlated only with age. N ormally, cortical density is age-dependent and its reduction is accompanied by compensatory geometry changes. Compared with control subjects, in our f emale 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). Conv ersely, in the males only cross-sectional area was reduced (p = 0.02). In c onclusion, in uremic patients we observed a selective cortical osteopenia, more evident in the female sex, and a sex-specific pattern of geometry impa irment, with resultant apparent increased bone fragility in the uremic wome n. We suggest that the prolonged PTH excess could be responsible, directly and/or interacting with estrogen deficiency.