The NTX assay in the follow-up of the osteoporotic patients: 3 years of alendronate treatment

These studies were conducted on 38 female patients treated with alendronate (10 mg/day, per os) for 3 years, because of osteoporosis. Of these patient s, 29 were in the menopausal age longer than 10 years, and the remaining ni ne patients were in menopausa shorter than 10 years. Urine sample were take n at the start of the treatment and every 6 months afterward for 3 years, a nd crosslinked N-telopeptides of type I collagen (NTx) have been measured i n them by means of an ELISA technique. Bone mineral density (BMD) has been recorded at the ultradistal (UDBMD) and mediodistal (MDBMD) region of radiu s of the non-dominant side. Body mass index (BMI) of the subjects has also been determined each time. The baseline values of NTx varied very much, sca ttered in a range of 11-215 nanomoles bone collagen equivalent/millimoles c reatinine (nM BCE/mM Cr), in average 59 +/- 46; those of UDBMD and MDBMD am ounted to 258 +/- 63 and 587 +/- 112 mg/cm(2), respectively. NTx, the BMD v alues and the menopausal age does not correlate with each other. Both BMD v alues increased almost linearly in the total study pool during the 3-years- long treatment, being 3.0-9.2 and 0.8-2.5% higher in terms of UDBMD and MDB MD, respectively. Urine NTx concentrations decreased during the same time 3 0-35%. It is concluded that monitoring of urine NTx levels may be very usef ul during antiosteoporotic treatments, because a reduction of NTx is an ind icator of the slowing down of bone turnover and the bone losses, as was obs erved during the alendronate therapy. (C) 1999 Elsevier Science Ireland Ltd . All rights reserved.