Responsiveness of endpoints in osteoporosis clinical trials

The usefulness of an endpoint depends in part on its responsiveness to clinically important change. From existing randomized controlled trials, the responsiveness of endpoints currently employed in osteoporosis clinical trials were examined. The responsiveness is presented as the sample size per group needed to show a statistically significant difference. The large variation found means that careful attention needs to be given to the responsiveness of the population studied when estimating the sample size.