Table 2.

Bone histomorphometric parameters of participants in a longitudinal bone biopsy study who underwent kidney transplantation

Bone Parameter	All Kidney Transplant Recipients at Baseline, n=37	Kidney Transplant Recipients with Repeat Bone Biopsy, n=27
Bone Parameter	All Kidney Transplant Recipients at Baseline, n=37	At Baseline	Two Years after Kidney Transplantation	P Value^a
Bone formation rate/bone surface (μm³/μm² per year)	21.1 (13.7–44.2)^b	20.3 (13.4–43.4)^c	10.4 (6.1–27.1)	0.02^a
Activation frequency (1/yr)	0.6 (0.2–1.1)^b	0.5 (0.1–1.0)^c	0.3 (0.1–0.6)	0.13
Osteoblastic surface/bone surface (Z-score)	0.2 (−3.2 to 5.5)^d	1.6 (−2.5 to 6.2)	−2.2 (−2.6 to −0.6)	0.008^a
Osteoclastic surface/bone surface (Z-score)	3.2 (−2.1 to 13.8)^d	9.9 (−1.5 to 13.8)	−0.2 (−2.3 to 2.5)	0.002^a
Osteoid surface/bone surface, %	39.1 (32.9–53)^d	40.2 (34–53.9)	34.1 (20.4–46.1)	0.08
Osteoid thickness, µm	6.9 (5.7–8.6)^d	7.3 (6.3–9.1)	8.9 (7.6–10.6)	0.02^a
Mineralization lag time, d	40.6 (27.6–110.2)^b	47.7 (28.7–117.5)^c	69.3 (42.8–162.8)	0.66
Bone volume/tissue volume, %	22.3 (14.3–26.5)^d	22.2 (13.9–26.8)	20.7 (13.6–27.8)	0.98
Lumbar spine T-score	−0.7 (−1.6 to 0.4)^e	−0.8 (−1.6 to 0.3)^f	−0.4 (−1.3 to 0.5)^g	0.41
Femoral neck T-score	−1.1 (−1.8 to −0.1)^e	−1.6 (−2.0 to −0.8)^f	−1.9 (−2.7 to −1.2)^g	0.03^a

All values are expressed as median (interquartile range).
↵a P value compares values 2 years after transplantation to values at baseline among kidney transplant recipients with repeat bone biopsy.
↵b n=25.
↵c n=23.
↵d n=32.
↵e n=36.
↵f n=26.
↵g n=22.