O95
BONE MINERAL DENSITY AND MICRO-ARCHITECTURAL CHANGES IN CKD
STAGES 4-5D.
SN Salam1, R Eastell2, A Khwaja1.
1
Sheffield Kidney Institute, Northern General Hospital, Sheffield.
2
Academic Unit of Bone Metabolism, University of Sheffield.
Background: Risk of fracture in chronic kidney disease (CKD) population is high and it is
associated with increased mortality. CKD affects bone quality through changes in bone
turnover, microarchitecture and mineralization. Furthermore, secondary hyperparathyroidism
has different effects on cortical and trabecular bone but dual-energy X-ray absorptiometry
(DXA) is unable to effectively differentiate these bone compartments. High resolution
peripheral quantitative computed tomography (HRpQCT) can overcome this limitation and
allow accurate calculation of volumetric BMD (vBMD), thus could be a more powerful
assessment of bone structure.
Aim: To compare bone mineral density (BMD) and micro-architectural parameters in CKD
stages 4-5D patients with controls.
Methodology: This is a cross-sectional study of CKD stages 4-5D patients and their age- and
sex-matched controls with estimated glomerular filtration rate (eGFR) >60ml/min/1.73m2. We
used DXA (Hologic Inc) to measure areal BMD (aBMD) of LS, hip and forearm. XtremeCT
(Scanco Medical) was used to obtain HRpQCT images of distal radius and tibia with image
resolution of 82um.
Results: This is preliminary results from 20 CKD patients (13 pre-dialysis, 7 dialysis) in our
study and their age- and gender-matched controls. Mean eGFR was 12ml/min/1.73m2 for predialysis patients and 78ml/min/1.73m2 for controls. 25% of each group were female. We found
that CKD patients had lower BMD measured by both techniques compared to controls. CKD
patients had lower aBMD by DXA but this was only significant at the hip.
At the tibia, total vBMD was significantly lower in CKD compared to controls and there was a
trend towards lower cortical and trabecular vBMD but this was not significant. At the radius,
total vBMD was lower in CKD but trabecular vBMD was significantly lower compared to
controls. Meanwhile, cortical vBMD in CKD at this site was similar to controls. We also found
thinner cortical bone at the tibia and thinner trabeculae at the radius in CKD.
Table 1: Mean vBMD and micro-architectural parameters on HRpQCT in CKD and controls.
CKD
Control
p value*
HRpQCT radius, mean (SD)
Total vBMD (mg/cm3)
281.8 (67.7)
317.1 (73.9)
0.12
Cortical vBMD (mg/cm3)
824.6 (63.4)
822.7 (80.2)
0.93
Trabecular vBMD (mg/cm3)
159.2 (49.8)
195.0 (41.2)
0.02
Trabecular thickness (mm)
0.06 (0.01)
0.07 (0.01)
0.01
HRpQCT tibia, mean (SD)
Total vBMD (mg/cm3)
274.7 (60.4)
322.2 (72.9)
0.03
Cortical vBMD (mg/cm3)
833.2 (68.9)
866.7 (73.2)
0.15
Trabecular vBMD (mg/cm3)
171.9 (38.1)
189.2 (48.0)
0.22
Cortical thickness (mm)
1.04 (0.34)
1.30 (0.39)
0.03
*p values were calculated using t-test.
Limitations: This is preliminary data from our on-going cross sectional study examining the
utility of imaging and bone turnover markers to predict bone histomorphometry.
Conclusion: HRpQCT is a useful research tool which can detect quantitative changes in BMD
and micro-architectural properties in CKD stages 4-5D patients. Provisional data suggests that
CKD is associated with different effects in trabecular and cortical bone. This needs to be
verified in larger study.