Men's Osteoporosis Support Group

Decline in BMD while on bisphosphonates and fracture risk

Clin Ther. 2008 Mar;30(3):443-52. Significance of a decline in bone mineral density while receiving oral bisphosphonate treatment. Sebba AI. PMID: 18405784. There is a full range of response in studies where bisphosphonates like Actonel (risedronate), Fosamax (alendronate) and Boniva (ibandronate) are used. In fact some individuals don't appear to benefit whatsoever and have no increase in bone mineral density (BMD) throughout the study. This paper is a review of the literature on this topic seeking to see if there is a relationship between nonresponse to bisphosphonate therapy and fracture risk. The results showed from 8 to 25% of patients after two years of treatment did not respond according to BMD results. They found that with either risedronate or alendronate, post hoc analysis of studies after two years showed a 38-50% reduction in fracture risk for responders when compared to nonresponders. However, nonresponders still have a reduced fracture risk of 38-60% compared to placebo.

Editor's comments. In a previous Update I reviewed an article on risedronate when results showed that increases in lumbar spine BMD accounted for only 18% of the fracture risk reduction. That apparently being the case because reduced fracture risk comes from both increased bone quantity and improved bone quality. As Sebba's review showed, the improvement in quality can come even when there is no increase in BMD. Remember that fracture risk reduction is really the reason we take medications for osteoporosis, not just to increase BMD. So this paper should be a positive sign for anyone who doesn't appear to be responding to therapy. Remember also that over the long term there appears to be a regression to the mean. That is, if you respond very well with initial therapy, you will tend to have reduced response later, or vice versa.

Return to Home