THE RESPONSE IN SPINAL BONE MASS TO TIBOLONE TREATMENT IS RELATED TO BONE TURNOVER IN ELDERLY WOMEN

To determine the ability of bone turnover to predict the response in b one mass during treatment with Tibolone, two biochemical markers of bo ne metabolism were evaluated [CrossLaps(TM) corrected for urinary crea tinine (CrossLaps(TM)/Cr.) and serum osteocalcin measured in a newly d eveloped assay (N-Mid)], Data from a 2-year double-blind, randomized t rial with 56 completing Tibolone-treated women and 13 placebo-treated women were studied, Bone mineral density in the spine (QDR-1000) and i ndices of bone turnover were determined every 3 months throughout the study, The response in bone mass was calculated as the percent annual change in bone mineral density from baseline and was determined from a total of nine measurements, The response in bone mass was correlated to prestudy values of CrossLaps(TM)/Cr. (r = 0.27; p < 0.05), but was uncorrelated to prestudy values of N-Mid, The changes from baseline of these two markers were significantly correlated with the response in bone mass from the 6 months' time point and throughout the rest of the study, i.e., at 1 year: CrossLaps(TM)/Cr.: r = 0.54; p < 0.001, N-Mid : r = 0.49; p < 0.001), The change from baseline in the two markers wa s clearly more predictive of the response in bone mass than the baseli ne values of these markers as evaluated in a multiple, linear regressi on-model. Within 1 year of Tibolone-treatment, measured changes in Cro ssLaps(TM)/Cr. and bone mineral density are at least equally predictiv e of the true response in bone mass over 2 years, These results indica te a possibility of monitoring Tibolone therapy with biochemical marke rs of bone turnover, at least on group basis. (C) 1997 by Elsevier Sci ence Inc.