Clinical usefulness of serum carboxyterminal propeptide of procollagen I and tartrate-resistant acid phosphatase determinations to evaluate bone turnover in patients with chronic renal failure.

We have studied the levels of the biochemical markers of bone formation total serum alkaline phosphatase, osteocalcin (BGP) and carboxyterminal propeptide of type I procollagen (PICP), the levels of the biochemical marker of bone resorption serum tartrate-resistant acid phosphatase (TRAP) and those of intact immunoreactive PTH (iPTH) in 30 patients at different stages of chronic renal failure (CRF), all of them without verifiable hepatopathy, and in 9 patients in hemodialysis with hepatopathy measured by the Knodell index. Sixteen control subjects were also studied. In the group of patients with CRF with or without hepatopathy, the levels of biochemical markers of bone turnover were significantly elevated with respect to those of control patients. We did not find any significant difference in the levels of these parameters between the groups with and without liver damage, in spite of the fact that TRAP and PICP are cleared mainly by the liver. Levels of TRAP and PICP correlated significantly with the other biochemical markers of bone turnover studied. The good relation observed between PICP, TRAP and the biochemical indexes of bone activity and iPTH levels suggests the clinical value of these markers in the follow-up of bone involvement in patients with CRF. On the other hand, the frequent hepatopathy found in patients with CRF does not seem to affect to a significant extent the diagnostic value of PICP and TRAP in this pathology.