Bisphosphonate Treatment Can Increase Thigh Bone Breaks

Editor's Choice
Main Category: Bones / Orthopedics
Article Date: 23 Feb 2011 - 9:00 PDT


In curious research, it is found that women who use bone mass loss inhibitors, or bisphosphonates, have a higher incidence of breaking their thigh bones, or femoral shaft, than women who use this defensive medication less.

In the primary analysis, researchers found that use of bisphosphonates for five years or longer was associated with a 2.7 times higher odds of hospitalization for subtrochanteric or femoral shaft fracture compared with transient use (less than 100 days in total) of bisphosphonates.

Bisphosphonates are a family of drugs used to prevent and treat osteoporosis. Bisphosphonates bind to the surfaces of the bones and slow down the bone resorping action of the osteoclasts (bone-eroding cells). This allows the osteoblasts (bone-building cells) to work more effectively.

Government approved bisphosphonates increase bone density and prevent fractures of the spine (vertebral fractures). Alendronate, risedronate and zolendric acid have also been shown to prevent hip fractures.

Fosamax for example, is used in men and women to treat or prevent osteoporosis that is caused by menopause or by taking steroids. Fosamax is also used to increase bone mass in men who have osteoporosis, and to treat Paget's disease of bone in men and women.

Up to about the age of 30, the body deposits more calcium into your bones than it takes from them. Estrogen also helps keep calcium in your bones throughout reproductive life. But when estrogen decreases in the first few years after menopause, bones can weaken and suffer rapid loss of calcium.

Designed to decrease activity of the cells that cause bone loss after menopause, with just one tablet a month, an approved drug named Boniva helps slow or stop the natural processes that dissolve bone tissue; it binds with and stays in bones throughout the month. Boniva is clinically proven to not only maintain bone density, but actually works with the body to help reverse bone loss. body to help reverse bone loss.

Further analysis suggested that more than half of subtrochanteric or femoral shaft fractures among women taking bisphosphonates for greater than five years were attributable to extended bisphosphonate use; and that approximately 10% of the subtrochanteric or femoral shaft fractures cases in the population might be prevented if no patient received more than 5 years of exposure. Among 52,595 women with at least five years of bisphosphonate therapy, a subtrochanteric or femoral shaft fracture occurred in 71 during the subsequent year and 117 within 2 years.

Older women who used bisphosphonates (medications that prevent loss of bone mass) for five years or more were more likely to experience "atypical" fractures involving the femoral shaft (bone in the leg that extends from the hip to the knee) or subtrochanteric (fractures in the bone just below the hip joint), compared to women with less usage. However, the absolute risk of these "atypical" fractures was low and bisphosphonate use was associated with a reduced risk of typical osteoporotic fractures.

The article adds:

"Approximately 50% of women older than 50 years will sustain an osteoporosis-related fracture during their lifetime, and 1 of 5 patients with an osteoporosis-related fracture will die within 12 months. Although randomized trials have shown that treatment with bisphosphonates reduces the risk of osteoporotic fractures, concerns have recently emerged that bisphosphonate-related suppression of bone remodeling may adversely influence bone strength."

An increasing number of case reports describe women with long-term bisphosphonate therapy who develop fractures involving the subtrochanteric or shaft region of the femur, considered atypical because of their location and characteristic appearance on x-rays. The U.S. Food and Drug Administration recently announced its intent to actively monitor instances of bisphosphonate-induced atypical fractures.

Laura Y. Park-Wyllie, Pharm.D., M.Sc., of the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Canada add from their related research:

"In summary, our findings provide strong evidence that prolonged bisphosphonate therapy is associated with an increased risk of subtrochanteric or femoral shaft fracture, although the absolute risk of these fractures is low. These findings also highlight the need for a thoughtful assessment of individual risk of fracture when considering extended bisphosphonate therapy and that long-term use of these drugs may warrant reconsideration, especially in patients at relatively low risk of fracture. It may be appropriate to consider a drug holiday for selected patients, particularly as the cumulative duration of bisphosphonate therapy surpasses five years. Additional research is needed to better understand the prognosis of subtrochanteric or femoral shaft fractures among frail older adults, identify the specific subgroups of long-term users at the highest risk for these adverse effects, and explore whether interruptions in therapy reduce the risk of subtrochanteric or femoral shaft fractures over the long term."

Source: Journal of the American Medical Association

Written by Sy Kraft, B.A.


Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

• Additional
• References
• Citations