Don't Fear the Fracture

Bisphosphonates for osteoporosis may carry low risk of atypical fractures

/ Author:  / Reviewed by: Robert Carlson, M.D

(RxWiki News) Past studies have raised concerns that a type of osteoporosis drug may boost the risk of unusual bone fractures. Now research suggests this risk may be overstated.

Researchers found low rates of unusual fractures among osteoporosis patients taking bisphosphonates.

"While atypical fractures associated with bisphosphonates can occur, their incidence is low, and fear of this rare side effect should not outweigh the known significant benefits of bisphosphonates, which have been proven to reduce fractures from weak bones," said the lead researcher.

"Talk to a specialist about the best treatment plan for osteoporosis."

For every 10,000 osteoporosis patients treated for one year with bisphosphonates, only two to 30 patients had one of these unusual fractures, according to the findings by John N. Mecchella, DO, of the Dartmouth Institute for Health Policy & Clinical Practice, and colleagues.

Osteoporosis makes your bones weak and prone to breaking. As you grow older, the rate at which you lose bone mass becomes greater than the rate that you form new bone mass. This means your bones become thinner and more fragile.

Bisphosphonates are a class of drugs used to treat osteoporosis and to prevent fractures caused by the condition. Examples of bisphosphonates include Boniva (ibandronate), Fosamax (alendronate), Actonel (risedronate), Atelvia (risedronate) and Reclast (zoledronic acid).

Past research has suggested that long-term use of bisphosphonates may cause an unusual kind of fracture - called atypical fractures - in the hips and thighs of osteoporosis patients. In light of this previous research, doctors and patients have become more timid about using these drugs.

"Deciding to start a medication for this disease requires weighing the risks and benefits of therapy. To help decision-making, we summarized available studies to describe the absolute risk of atypical fractures," said Dr. Mecchella.

The researchers found that the highest estimated rates of atypical fractures were 3.4 fractures per 1,000 patient-years - a rate that is much lower than estimates for more common fractures of osteoporosis called recurrent osteoporotic fractures. These more common fractures happen at a rate of about 100 per 1,000 patients per year.

For their research, Dr. Mecchella and colleagues looked at 12 past studies in which osteoporosis patients were taking bisphosphonates. Within these studies, several hundreds of thousands of patients were followed anywhere from less than 1 year to 10 years of bisphosphonate use. Out of all these patients, only 1,440 had an atypical fracture.

"Discussions regarding bisphosphonate therapy should put both benefits and harms in appropriate context so that decisions are driven by evidence, not fear," the authors concluded.

The authors disclosed no conflicts of interest.

The research was presented at the American College of Rheumatology's annual meeting. As such, the study has yet to go through a peer-review process to be published.

Reviewed by: 
Review Date: 
November 13, 2012
Last Updated:
November 19, 2012