Monday, May 09, 2011

Oral Bisphosphonates: Study - Absolute Risk for Femur Fracture Low with Bisphosphonates

I have written a number of pieces about the problems associated with bisphosphonates and osteonecrosis of the jaw. My latest post is here.

Now, there is a new study published in the New England Journal of Medicine which sheds new light on the advantages vs. risks of taking these drugs.
Almost 78% of all Swedish women aged 55 years and older who sustained an atypical femur fracture in 2008 had taken bisphosphonates, but the absolute risk for such breaks is small enough to justify prescribing the drugs, according to a study published in the May 5 issue of the New England Journal of Medicine (NEJM).

For patients taking bisphosphonates, the age-adjusted relative risk for an atypical femur fracture — a clean, horizontal break spreading from the lateral side and occurring with minimal or no trauma — was 47.3%, the study reported. The crude incidence of the fractures was 0.09 per 10,000 patient-years among women who had never taken the drug compared with 5.5 among those who had ever taken it.

These results "should be reassuring for bisphosphonate users," write lead author Jörg Schilcher, MD, from the Department of Experimental and Clinical Medicine, Faculty of Health Science, Linköping University, Linköping, Sweden, and colleagues. "With a correct indication, the benefits of fracture prevention...will greatly outweigh the risk of atypical femoral fracture."
So, in other words, the benefits of preventing fractures by taking the medications outweigh the risk of an atypical leg (femur) fracture.

So, how does this apply to dentistry?

With more and more patients taking these drugs to prevent osteoporosis, and for longer periods of time, dentists will have to be scrupulous in their medical histories. Osteonecrosis of the jaw, while rare, is a known and serious complication.

An undisplaced femoral fatigue fracture associated with bishosphonate treatment. NIH photo
This study echoes the paper published in February in the Journal of the American Medical Association which I cited a few months ago. The AMA paper is here.
Experts interviewed by Medscape Medical News call the study definitive because researchers not only studied a massive number of participants — all 1.5 million women in Sweden who were aged 55 years or older in 2008 — but also reviewed the x-rays of nearly all those who had particular kinds of femur fractures.

"It's the largest and most comprehensive study of this issue that I've seen," said Sundeep Khosla, MD, president of the American Society for Bone and Mineral Research (ASBMR) and a professor of medicine and physiology at the Mayo Clinic in Rochester, Minnesota.

The study's conclusions echo those in other recent studies on the worrisome fractures and the bone-building drugs for osteoporosis. An article published in February in the Journal of the American Medical Association, for example, reported that long-term use of bisphosphonates boosted the risk for these fractures, but those authors noted that the absolute risk for fracture is low and is outweighed by the benefits of the therapy.
And, what about drug holidays - especially since the risk of fracture declines rapidly after drug withdrawal?
Because it is not clear how long patients with osteoporosis can be safely treated with bisphosphonates, the ASBMR recommends that clinicians consider discontinuing them after 5 years. At that point, many physicians give their patients a "drug holiday" for 1 or 2 years and then resume the therapy. Dr. Shane said that the rapid decline in fracture risk after drug withdrawal helps justify a holiday.

"Now there seems to be evidence that giving patients intermittent drug holidays is appropriate to do," she said. Dr. Khosla agreed, saying the decrease in fracture risk provides "reassurance that a [drug holiday] is good clinical practice."
Again for dentists, it will be esepcially important to monitor our patients for when they are on or off the medications. Since dental visits may be episodic, and in older patients only in case of an emergency e,g. tooth extraction, proper dental/medical records are mandatory. Appropriate consultation with the patient's physician is indicated. Treatment plans for dental examination and/or treatment either prior to initial treatment or before resumption of treatment with these drugs would be beneficial to patients.

I will look forward to additional studies on the risk of dental complications using a drug holiday approach - with resumption of drug use.

In the meantime, Flap urges caution for patients taking ORAL Bisphosphonate medications. And,please patients update your health history and tell your dentist if you are using these drugs.


Revisiting Bisphosphonates and Femur Fractures

Oral Bisphosphonates Associated with a SLIGHTLY Elevated Risk of Developing Osteonecrosis of the Jaw?

New Dentistry Cause for Alarm for Patients Who Use Bisphosphonates – Fosamax, Actonel, Boniva?

Dentistry Today: Bisphosphonates: Zometa (zoledronic acid) & Aredia (pamidronate disodium) Associated with Osteonecrosis of Jaw – REDUX

Bisphosphonates: Zometa (zoledronic acid) & Aredia (pamidronate dis odium) Associated with Osteonecrosis of Jaw

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