Bisphosphonates Worth Taking Despite Tiny Thigh Fracture Risk

Although bisphosphonates are linked to a tiny risk of a rare type of thigh fracture, their benefits are still far greater than their dangers for the prevention and treatment of osteoporosis, Swedish researchers wrote in the NEJM (New England Journal of Medicine).

Orthopedic surgeons have reported a growing number of cases of patients on bisphosphonates having severe fractures in which the thighbone snaps. Over the last few years experts have been trying to determine whether taking bisphosphonates might be linked with atypical femur fractures.

An atypical femur fracture is a clean, horizontal break that spreads from the later side and occurs with minimal or no trauma.

Nobody really knows why some patients develop this type of fracture – are the bisphosphonates causing them, or some other variables, such as a genetic factor? Studies do not seem to have consistent findings on this matter, the authors explained.

In October 2010, the FDA (Food and Drug Administration) altered the labeling on bisphosphonates, warning about a potential risk of atypical fractures.

In this latest study, researchers from Linköping University, Sweden, gathered data on 1.5 million Swedish females aged at least 55 years in 2008. They looked at 1,234 X-rays out of 1,271 women who had had fractures, of which 59 had atypical femur fractures.

They compared the women with atypical fractures with 263 females who had fractures in a similar location (controls). 78% of the women with atypical fractures had been taking bisphosphonates, while only 10% of the controls had.

Even so, the authors explained, atypical fractures are still very uncommon, and the benefits of bisphosphonates far outweigh the risks.

Lead author Jörg Schilcher, MD., said:

“(these results).. should be reassuring for bisphosphonate users. With a correct indication, the benefits of fracture prevention will greatly outweigh the risk of atypical femoral fracture.”

Bisphosphonates are typically prescribed to post-menopausal females to prevent fractures linked to osteoporosis. 36.5 million prescriptions were written for bisphosphonates in 2010, according to IMS Health. In the USA, bisphosphonates represent a $4.2 billion per year business.

Examples of bisphosphonates include Fosamax, Aredia, Boniva, Aclasta, Zometa and Actonel.

Orthopedic surgery professor Per Aspenberg explained that a patient who stopped taking bisphosphonates for one year had a 70% lower risk of fracture. He believes we need more research on this matter.