Serum markers of bone turnover in dialyzed patients grouped by level of intact parathyroid hormone.

We evaluated serum markers of bone turnover (BT) in patients suspected to have low bone turnover (LBT) given their serum level of intact parathyroid hormone (iPTH). Studies were carried out in 30 dialyzed patients. In 9 patients, iPTH was below 100 pg/mL (LBT group), and in 21, it was above 100 pg/mL (non-LBT group). Other measured laboratory parameters included serum concentrations of cyclase inactivating parathyroid hormone (CAP), osteoprotegerin (OPG), OPG ligand (OPGL), inorganic phosphates, total calcium, creatinine, urea, serum alkaline phosphatase (ALP) activity, and blood pH. The LBT group showed significantly lower levels of iPTH (39.0 +/- 30.7 pg/mL), CAP (23.2 +/- 16.9 pg/mL), cyclase inactive parathyroid hormone (CIP: 15.8 +/- 15.0 pg/mL), and total ALP (83.9 +/- 26.2 IU/L) than did the non-LBT group (393 +/- 304 pg/mL, 268 +/- 216 pg/mL, 126 +/- 96 pg/mL, and 202 +/- 167 IU/L respectively). We observed no significant differences between the groups in the other examined parameters. When results were adjusted for sex, age, and dialysis modality and duration, differences remained significant only for iPTH and CIP. Our data indicate that a serum CIP concentration below 25 pg/mL has a significance similar to that of an iPTH concentration below 100 pg/mL in determining which dialyzed patients likely have LBT.