Biochemical markers to predict long-term BMD changes during osteoporosis therapy
Using urinary NTx biochemical markers to predict bone mineral density (BMD) changes in patients on osteoporosis medications. J Clin Endocrinol Metab. 2005 Feb 15; [Epub ahead of print]. Greenspan SL, Resnick NM, and Parker RA. PMID: 15713726. A previous Update to this site described the various biochemical markers of bone metabolism used to help determine the amount of bone formation or resorption that is occurring at the time the test is performed. The Greenspan and others study shows an interesting potential use of urinary NTx for individuals that are just starting osteoporosis therapy. Although this study involved only elderly postmenopausal women, one could assume that it would apply to anyone taking bisphosphonates (and probably other non-hormonal therapies) for osteoporosis. Both the NTx and the medications have the same mechanism of action in men and women and that mechanism is not age-dependent. You can read the abstract noted above for details on the study. The important finding was that when study participants were divided into thirds according to the mean degree of reduction in urinary NTx biochemical markers of bone turnover at the initial six-month test, those women in the highest tertile had the greatest increase in BMD at the end of the three year study. This amounted to nearly a doubling of the increase in BMD for the spine and nearly tripling of the BMD at the hip when comparing the highest one third to the lowest one third. Editor's comments: This would appear to be an important finding. Rather than waiting for a year or two to get the dual-energy X-ray absorptiometry (DXA) results, having a urinary NTx test performed after six months of therapy on, e.g., Fosamax or Actonel, appears to offer a good indication of the effectiveness of long-term therapy. I very often hear from men who are not getting the results they had hoped for after a year or more on Fosamax or Actonel. Had they been given the six-month urinary NTx, this might have given them and their physician's an indication that minimal response to therapy should be expected. Knowing this a one-year DXA could have been done to confirm the NTX findings and/or other types of therapy could be tried early on rather than waiting many months or years before confirming the need to try something different. Or, vice versa, a six-month urinary NTx showing a great reduction in bone breakdown markers would indicate that long-term results should be excellent. In reading over this study, the one thing I couldn't find that would be very valuable would be to know why or what it is about the highest one-third of responders to NTX that accounts for the improved response. Do these patients comply better and thus take their medications more regularly? Or, is there some identifiable feature or trait they have that others don't? If future studies could find that key to increasing the response to therapy, it might be beneficial.
Pharmacotherapy of osteoporosis in men
Expert Opin Pharmacother. 2005 Jan;6(1):45-58. Diamond, TH, PMID: 15709882. If you would like to read an excellent summary of all the various pharmacotherapies available for men with osteoporosis, I suggest getting a copy of this article. It is a review of studies that involved men and includes the following therapies: Bisphosphonates, including alendronate (Fosamax), risedronate (Actonel), cyclical etidronate, pamidronate, and zoledronic acid; parathyroid hormone (Forteo); testosterone; calcium and vitamin D; calcitonin, estrogen and selective estrogen-receptor modulators; growth hormone and insulin growth factor; non-pharmacological therapies such as hip protectors. If you'll give the journal information to your local librarian you should be able to get a free copy from the National Library of Medicine.