Abstract: FR-OR06
Early Changes in Bone Turnover Markers Predict Bone Loss After Kidney Transplantation
Session Information
- Advances in Mineral Metabolism and Nephrolithiasis
November 04, 2022 | Location: W314, Orange County Convention Center‚ West Building
Abstract Time: 05:15 PM - 05:24 PM
Category: Transplantation
- 2002 Transplantation: Clinical
Authors
- Joergensen, Hanne Skou, Katholieke Universiteit Leuven, Leuven, Belgium
- D'Haese, Patrick, Universiteit Antwerpen, Antwerpen, Belgium
- Cavalier, Etienne, Universite de Liege, Liege, Belgium
- Evenepoel, Pieter, Katholieke Universiteit Leuven, Leuven, Flanders, Belgium
Background
Bone mineral density (BMD) changes are highly variable after kidney transplantation (TX) with subgroups of patients gaining or losing BMD in the first post-TX year. We investigated whether early changes in bone turnover markers (BTMs) could predict the BMD trajectory, which could enable targeted therapy.
Methods
BMD was measured at TX and 1 yr and parathyroid hormone (PTH) and BTMs at TX, 3 mo, and 1 yr (n=230). Paired transiliac bone biopsies were available in a subset (n=49).
Results
Lumbar spine BMD loss at 1 yr was associated with higher PTH and BTMs at TX, with greater decreases in BTMs at 3 and 12 mo (Table). Trajectories of BTMs differed for patients gaining and losing BMD (Figure). By bone biopsy, patients with lumbar spine BMD gain vs loss had greater decreases in osteoid volume (-1.7 vs +2.2%, p=0.01) and surface (-9.09 vs +8.97uM, p=0.01). Changes in cortical porosity and thickness by micro-CT (n=19) were minimal and unrelated to changes in BMD.
Conclusion
Rapid mineralization of osteoid results in substantial BMD gain post-TX in a subset of patients. Changes in bone turnover markers during the first 3 mo can be used to predict the trajectory of BMD in the first post-TX yr.
Table
| Biochemistry | Lumbar spine BMD loss (<-2.5%) (n=78) | Lumbar spine BMD neutral (n=86) | Lumbar spine BMD gain (>2.5%) (n=66) | P |
| Biointact parathyroid hormone (TX), xUNL | 2.78 (1.40; 4.49) | 3.22 (2.01; 5.71) | 4.83 (2.73; 8.69) | <0.001 |
| Bone-specific alkaline phosphatase (TX), ug/L | 17.4 (13.6; 23.8) | 18.8 (14.8; 29.3) | 30.8 (21.5; 49.5) | <0.001 |
| Tartrate resistant acid phospahtase isoform 5b (TX), U/L | 4.73 (3.17; 6.58) | 5.03 (3.73; 7.25) | 5.99 (3.94; 9.08) | 0.01 |
| Estimated glomerular filtration rate (12mo), mL/min/1.73m2 | 48.02 (36.37; 57.56) | 46.00 (38.07; 54.90) | 51.58 (43.91; 60.14) | 0.03 |
| Biointact parathyroid hormone (12mo), xUNL | 1.17 (0.69; 2.11) | 0.97 (0.64; 1.94) | 1.01 (0.68; 1.79) | 0.43 |
| Bone-specific alkaline phosphatase (12mo), ug/L | 20.6 (13.7; 29.2) | 15.6 (11.3; 23.7) | 13.8 (10.4; 21.2) | 0.001 |
| Tartrate resistant acid phospahtase isoform 5b (12mo), U/L | 3.89 (2.93; 5.20) | 3.06 (2.15; 4.14) | 2.71 (1.78; 4.12) | <0.001 |
| ΔBALP (3mo), % | -7.8 (-32.3; 35.6) | -23.4 (-47.6; 3.8) | -34.1 (-61.7; -1.7) | <0.001 |
| ΔTRAP5b (3mo), % | -26.8 (-48.2; 0.3) | -44.5 (-58.6; -20.3) | -52.2 (-67.3; -32.4) | <0.001 |
| ΔBALP (12mo), % | -1.1 (-25.8; 67.5) | -22.7 (-48.1; 18.8) | -51.5 (-70.8; -30.6) | <0.001 |
| ΔTRAP5b (12mo), % | -13.1 (-41.6; 13.5) | -38.7 (-57.0; -17.1) | -54.9 (-67.6; -42.7) | <0.001 |
Median(IQR) with P by Kruskal-Wallis test