Bone Biopsy Results in Chronic Kidney Disease: a Single-Center Experience

Although bone histology remains the diagnostic standard in renal osteodystrophy (ROD), biomarkers are used more commonly. Data comparing bone biopsy results and biomarkers of bone metabolism remain sparse.

This is a single-center retrospective analysis of bone biopsy results (105) stratified by renal function, compared with intact parathyroid hormone (iPTH), bone-specific alkaline phosphatase (BAP) and other biomarkers. We tested associations with high-turnover ostitis fibrosa (OF) and mixed uremic osteodystrophy (MUO), i.e. classes I and III according to Delling's classification.

37% of patients had CKD stage 3-5 not on dialysis (CKD NOD) and 50% CKD stage 5 requiring haemodialysis (CKD 5D). iPTH was significantly higher in CKD 5D with high-turnover ROD, 26 (18) versus 8 (9) pmol/l (p< 0.001). BAP showed no association. In CKD NOD, high-turnover ROD was associated with elevated iPTH, 32 (44) versus 8 (11) pmol/l (p=0.001), and BAP, 39 (32) versus 16 (7) U/l (p=0.01). iPTH achieved receiver operator characteristic (ROC) areas under the curve (AUC) of 0.83 (P=0.003) and 0.91 (P=0.019) for high-turnover ROD among CKD 5D and CKD NOD patients, respectively. An iPTH cutoff of 12.8 (CKD 5D) and 13.5 pmol/l (CKD NOD) reached sensitivities and specificities of 0.83, 0.91 and 1.00, 0.91, respectively. In CKD NOD, BAP achieved an AUC of 0.93 (P=0.013) and with a cutoff at 19.8 U/l a sensitivity and specificity of 1.00, 0.91, respectively.

In CKD 5D patients, high-turnover ROD was associated with elevated iPTH at a low cutoff but not with BAP. The same diagnosis in CKD NOD was associated both with iPTH and BAP.