Kidney Week

Abstract: TH-OR35

Reliability of Time-Lapse High-Resolution Peripheral Quantitative CT (HR-pQCT) in Determining Bone Remodeling in Patients with ESKD

Session Information

• CKD-MBD and Kidney Stones: Novel Insights
  October 24, 2024 | Location: Room 6D, Convention Center
  Abstract Time: 05:40 PM - 05:50 PM

Category: Bone and Mineral Metabolism

• 502 Bone and Mineral Metabolism: Clinical

Authors

• Zhou, Minhao, University of California San Francisco, San Francisco, California, United States

Minhao Zhou, PhD

• Sadoughi, Saghi, University of California San Francisco, San Francisco, California, United States

Saghi Sadoughi

• Go, Lauren, University of California San Francisco, San Francisco, California, United States

Lauren Go

• Yu, Isabel, University of California Berkeley, Berkeley, California, United States

Isabel Yu

• Wu, Po-hung, University of California San Francisco, San Francisco, California, United States

Po-hung Wu, PhD

• Saeed, Isra, University of California San Francisco, San Francisco, California, United States

Isra Saeed

• Fan, Bo, University of California San Francisco, San Francisco, California, United States

Bo Fan, MD

• Salusky, Isidro B., University of California Los Angeles David Geffen School of Medicine, Los Angeles, California, United States

Isidro B. Salusky, MD, FASN

• Nickolas, Thomas, Columbia University Irving Medical Center, New York, New York, United States

Thomas Nickolas, MD, MS

• Ix, Joachim H., University of California San Diego Department of Medicine, La Jolla, California, United States

Joachim H. Ix, MD, FASN

• Kazakia, Galateia J., University of California San Francisco, San Francisco, California, United States

Galateia J. Kazakia, PhD

Background

Patients with end-stage kidney disease (ESKD) have elevated fracture risk in part due to abnormally high or low bone turnover, requiring treatment from patient-specific turnover assessments. However, a reliable, accessible, and non-invasive tool to determine turnover in individual patients does not exist.
High-resolution peripheral quantitative computed tomography (HR-pQCT) captures high-resolution in vivo bone microstructure. Time-lapse (TL) analysis uses longitudinal spatially-aligned HR-pQCT scans to evaluate temporospatial bone remodeling (FigA). This work evaluates the feasibility of TL HR-pQCT to assess turnover in patients with ESKD. We hypothesized that a 2-month TL period could capture remodeling in ESKD.

Methods

Distal tibia and radius scans were acquired on XtremeCT II. Bone formation and resorption fraction (BFF and BRF) were evaluated with respect to baseline integral, cortical, and trabecular bone volumes. Total and net bone turnover (TBT and NBT) were calculated as BFF+BRF and BFF-BRF, respectively (FigB). All rates were annualized (%/year). Annualized least significant change (LSC) in remodeling was established from a cohort of 15 healthy participants scanned twice ~1 year apart.

Results

Eight patients with ESKD on dialysis underwent 2 scans ~2 months apart (mean months on dialysis: 46; FigC). TL analysis showed that BFF and BRF in the ESKD cohort were >2- and >6-fold higher than the respective LSC (FigD-E). Radius cortical bone loss of 10.6%/year was found in ESKD (FigE).

Conclusion

This study showed that individual bone remodeling in ESKD can be captured by TL HR-pQCT in a 2-month TL period, shorter than that needed for gold standard tetracycline double-labeled bone biopsy. The assessed trabecular BFF in ESKD (9.6-21.3%/year) agrees with reported histomorphometric formation (3.5-22.4%/year), and the observed cortical bone loss aligns with known ESKD pathology, both verifying the reliability of TL HR-pQCT in ESKD bone turnover assessments. Future work will further validate TL HR-pQCT.