Abstract: SA-PO886

Bone Disease Post Kidney Transplantation – Beyond Bone Mineral Density

Session Information

  • Mineral Disease: CKD-Bone
    November 04, 2017 | Location: Hall H, Morial Convention Center
    Abstract Time: 10:00 AM - 10:00 AM

Category: Mineral Disease

  • 1203 Mineral Disease: CKD-Bone

Authors

  • Sharma, Ashish K., The Royal Melbourne Hospital, Parkville, Victoria, Australia
  • Toussaint, Nigel David, The Royal Melbourne Hospital, Parkville, Victoria, Australia
  • Holt, Stephen G., The Royal Melbourne Hospital, Parkville, Victoria, Australia
  • Elder, Grahame J., Westmead Hospital, Sydney, New South Wales, Australia
  • Baldock, Paul A., Garvan Institute, Sydney, New South Wales, Australia
  • Honma, Kiara, University of Pennsylvania, Philadelphia, Pennsylvania, United States
  • Rajapakse, Chamith S., University of Pennsylvania, Philadelphia, Pennsylvania, United States
  • Masterson, Rosemary, The Royal Melbourne Hospital, Parkville, Victoria, Australia
Background

Post-transplant bone disease in kidney transplant recipients (KTRs) is traditionally characterised by severe loss of bone mineral density (BMD) and increased fracture risk. Recent studies have shown less dramatic decrease in BMD at various skeletal sites. Bone microarchitecture changes post-transplant are not well defined and cannot be accurately evaluated with bone biomarkers and dual energy x-ray absorptiometry (DXA). Bone biopsy is invasive and infrequently performed. We longitudinally evaluated changes in BMD, microarchitecture and biomarkers post kidney transplantation, using high-resolution magnetic resonance imaging (MRI, distal tibia), peripheral quantitative computed tomography (pQCT, radius), DXA and biomarkers of mineral metabolism.

Methods

Twelve adult live donor KTRs (mean age 49+/-10.96, 66% M) underwent MRI, pQCT and DXA (hip, spine) at baseline and 12 months post transplantation. Laboratory testing was performed at baseline, 6 and 12 months.

Results

Compared with baseline, 12-month MRI (tibia) showed deterioration in indices of trabecular network integrity - surface to curve ratio (S/C, -15%, p=0.042) and erosion index (EI, +19%, p=0.005). Changes were also seen in cortical thickness (+4.6%, p=0.0269) and cortical area (+11.5%, p=0.03). Numerical changes in areal BMD and volumetric BMD were not statistically significant. Interval changes in S/C and EI correlated with total hip T-score (DS/C; r= 0.70, p=0.01 & EI; r=-71, p=0.009) and trabecular vBMD at radius (DS/C; r= -0.68, p=0.015 & DEI; r=71, p=0.009). There was no significant difference in serum calcium, but PTH and phosphate levels decreased after 12 months (-80.5%, p=0.03 & -49.3%, p<0.001 respectively). Changes in PTH were inversely predictive of BMD at the lumbar spine (r=-0.58, p=0.04) and femoral neck (r=-0.69, p=0.014) but were unrelated to cortical parameters.

Conclusion

Post-transplantation, there was deterioration in trabecular bone quality and network without significant changes in trabecular volume, structural parameters and BMD at central or peripheral sites. The preservation of cortical structure in our cohort is differs from recent studies and highlights the heterogeneous nature of histologic changes and multifactorial pathology of post-transplant bone disease.

Funding

  • Commercial Support