Changes in Bone Resorption Marker at One Month Predict Changes at Six Months in Patients Treated with Alendronate

Ninety-nine postmenopausal Japanese women were evaluated to assess whether changes at one month in urinary NTX bone resorption marker as a result of alendronate treatment enable prediction of changes at 6 months. The percentage change at one month significantly correlated with that at 6 months (R 2 � 0.290, P0.0001) and predicted the changes at 6 months with sensitivity 72.2%, specificity 60.0%, positive predictive value 87.7%, and negative predictive value 35.5%, respectively. This study demonstrated that changes in bone resorption marker at one month could be used as a reliable method to monitor the effects of alendronate treatment, and to predict the response at six months.