title: Cortical pQCT measures are associated with fractures in dialysis patients.
abstract: To determine if pQCT could identify HD patients with fractures, we conducted a cross-sectional study in 52 men and women on HD. We found that cortical, but not trabecular, pQCT measures were associated with fractures.
  
  
  BACKGROUND
  Fractures are common in hemodialysis (HD) patients, yet DXA is inconsistently associated with fractures. One explanation for this lack of association may be that HD patients have a selective decrease in cortical density not identified by standard DXA.
  
  
  METHODS
  We used pQCT to examine cross-sectional associations between cortical and trabecular measures and fractures in 36 men and 16 women, > or = 50 years of age, on HD for at least 1 year. We confirmed low-trauma nonspine fractures since starting HD. Prevalent vertebral fractures were identified by morphometry of lateral spine X-rays. pQCT measurements of the nondominant radius included trabecular density, cortical density, total area, cortical area, and cortical thickness. We also obtained DXA measurements of the hip and lumbar spine. We used logistic regression models, adjusted for age, weight, and sex, to examine the association between fracture (vertebral and/or self-reported nonspine) and each pQCT measure. Results are reported as ORs per SD decrease in the independent variable.
  
  
  RESULTS
  The mean age was 65.8 +/- 9.0 (SD) years, the mean weight was 72.3 +/- 15.6 kg, most (32 of 52) subjects were white, and there were 32 fractures in 27 subjects (prevalent vertebral fracture or low-trauma fracture) since starting dialysis. A decrease in cortical density was associated with fractures (OR = 16.67; 95% CI: 2.94-83.33), as was a decrease in cortical area (OR = 3.04; 95% CI: 1.28-7.25) and a decrease in cortical thickness (OR = 3.26; 95% CI: 1.36-7.87). Fractures were not associated with pQCT trabecular density (OR = 1.18; 95% CI: 0.6-2.33), total area (OR = 1.1; 95% CI: 0.59-1.7), or DXA measurements of the hip and spine.
  
  
  CONCLUSIONS
  Cortical parameters of the radius were associated with fractures in HD patients. If confirmed in prospective studies, these findings may explain the lack of association between fracture and standard DXA measurements and raise the possibility that pQCT could be used to identify HD patients at high risk of fracture.
authors.affiliation: Department of Medicine, Division of Endocrinology and Metabolism, St Michael's Hospital, University of Toronto, Toronto, Canada. sophie.jamal@utoronto.ca
authors.forename: Sophie A
authors.initials: SA
authors.lastname: Jamal
authors.forename: Jeremy
authors.initials: J
authors.lastname: Gilbert
authors.forename: Christopher
authors.initials: C
authors.lastname: Gordon
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Bauer
mesh_terms: D000368:Aged; D015519:Bone Density / Q000502:physiology; D003430:Cross-Sectional Studies; D005260:Female; D050723:Fractures, Bone / Q000150:complications / Q000453:epidemiology*; D006615:Hip / Q000033:anatomy & histology; D006801:Humans; D016015:Logistic Models; D008159:Lumbar Vertebrae / Q000033:anatomy & histology; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis; D014057:Tomography, X-Ray Computed