Abstract

OLIVERI, Beatriz; WITTICH, Ana C.; NADAL, Miguel A.  and  ZENI, Susana N.. Serum b-Type I collagen carboxyterminal telopeptide (b-CTXs) and bone involvement in chronic renal failure. Medicina (B. Aires) [online]. 2005, vol.65, n.4, pp.321-328. ISSN 0025-7680.

An increase in parathyroid hormone (PTH) levels in chronic renal failure (CRF) induces bone abnormalities known as renal osteodystrophy (ROD). The aim of the present study was to evaluate alternative biochemical methods to bone biopsy, to evaluate changes in bone remodeling in renal patients. Intact PTH (iPTH) and bone markers were measured in 43 predialysis (PD), 49 hemodialysis patients (HD) and 185 controls. bCTXs, bone alkaline phosphatase (bAL), iPTH were higher and creatinine clearance (Ccr) was lower in PD and HD compared with controls (p<0.0001). In both renal groups, a positive correlation was found between iPTH and both bCTXs and bAL (p<0.0001) and between bCTXs and bAL (p<0.002). PD patients with Ccr <40 ml/min had higher iPTH, bAL and bCTXs (p<0.004, p<0.05 and p<0.001, respectively) than patients with Ccr>40 ml/min. bCTXs (p<0.05) in PD and bCTXs and bAL in HD patients were higher than controls, even when iPTH was within normal range (<65 pg/ml). Patients with severe secondary hyperparathyroidism showed higher bone markers than patients with normal or moderately increased iPTH (p<0.001). These results suggest that even when there is no increase in iPTH, bone remodeling increases (possibly due to other factors) exhibiting higher bone resorption, and bCTXs would seem to be an adequate non-invasive tool to assess early bone changes in CRF and prevent future fractures. Bone marker measurements in ROD would be useful to identify patients who may require bone biopsy. However, further studies comparing both methods must be performed before replacing bone biopsy with serum b-CTX.

Keywords : renal insufficiency; parathyroid hormone; bone biochemical markers; serum b-collagen type I carboxyterminal telopeptide.

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