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Abstract: SA-PO193

Changes in Bone Quality Over 2 Years in Patients With CKD Stages 2-4

Session Information

Category: Bone and Mineral Metabolism

  • 402 Bone and Mineral Metabolism: Clinical

Authors

  • Mohamed, Amr El-Husseini, University of Kentucky Medical Center, Lexington, Kentucky, United States
  • Lima, Florence, University of Kentucky Medical Center, Lexington, Kentucky, United States
  • Meulendyke, Kelly, University of Kentucky Medical Center, Lexington, Kentucky, United States
  • Abdalbary, Mohamed Mamdouh, Mansoura University, Mansoura, Egypt
  • Nagy, Eman, Mansoura University, Mansoura, Egypt
  • Srour, Habib, University of Kentucky Medical Center, Lexington, Kentucky, United States
  • Faugere, Marie-Claude M., University of Kentucky Medical Center, Lexington, Kentucky, United States
  • Malluche, Hartmut H., University of Kentucky Medical Center, Lexington, Kentucky, United States
Background

Renal osteodystrophy develops early with loss of kidney function. It encompasses loss of bone quantity and reduced bone quality. This study used Fourier Transformed Infrared Spectroscopy (FTIR) to measure bone quality.

Methods

20 patients (pts) with CKD II-IV underwent iliac crest bone biopsies for FTIR, bone histomorphometry, and dual-photon absorptiometry (DXA) for bone mineral density (BMD) of hip and spine. FTIR parameters included mineral:matrix ratio (M/M), carbonate:phosphate ratio (C/P), collagen crosslinks (Cx) and crystal size (CS). In addition, serum biochemical parameters were measured, including eGFR, Ca, P, iPTH, BSAP, Trap-5B, sclerostin, i and c-term FGF-23, α-klotho, and Activin A. All tests were done at baseline and after 2-3 years of observation with continuation of the same clinical management following KDIGO guidelines.

Results

Age of pts was 60 ± 11 y with 55% female, 65% White, 30% Black, 5% Asian, 55% DM2, 100% HTN, 10% CKD II, 70% CKD III, and 20% CKD IV. Mean eGFR did not significantly change but declined in 9 pts. At beginning of study bone turnover was low in 85% of pts versus 75% at the end; bone volume was low in 25% versus 47% at the end. Mineralization was normal throughout. There was a trend for M/M and CS to go down and histologically, bone turnover increased significantly with increase in the number of pts in the normal range.
Change in (D) Cx correlated negatively with DP (p=0.026). There was a negative correlation between DM/M and baseline iPTH (p=0.002), and a positive correlation between DCS and DiPTH. DC/P correlated positively with Dα-Klotho (p=0.002), and negatively with baseline α-klotho (p=0.011). DCS corelated negatively with D trabecular separation (p=0.017) and positively with D spine T score (p=0.050).

Conclusion

The study confirms presence of abnormal bone quality in addition to loss of bone quantity in pts with CKD II-IV. Over 2 years of observation, there was a significant further loss of bone volume by DXA and an increase in turnover towards the normal range by histology. Bone quality parameters trended towards normal and were significantly correlated with changes in parameters indicative of improvement in bone turnover. These results call for management strategies addressing both bone quality and quantity in pts with CKD.

Funding

  • NIDDK Support