Study Links Osteoporosis Drugs With Fractures

The osteoporosis drugs known as bisphosphonates increase the risk of getting unusual thigh bone fractures , as experts have suspected, according to a new Swedish study.

These fractures, however, are very rare. The study also shows that the risks of developing them is low.

According to Per Aspenberg (MD, PhD), a researcher in orthopaedics at Linkoping University in Sweden, when prescribed correctly, the total benefit of drugs that prevent all kinds of fractures is greater than the risk of suffering from rare fractures.

The research involved 12,777 elderly women, 55+ who sustained a fracture to their thigh bone. The link between bone-building medications and unusual fractures was strong, he found.

Aspenberg tells WebMD, experts have been debating whether or not there's a cause and effect relationship. The only consensus so far, [before Aspenberg's study], is that there is weak association."

He says, "Our study shows an extraordinarily strong association. A dose-response relation." When he examined the data in various ways, the link was constant. He also took into consideration other drugs that the women were using or any other conditions they suffered. The link held.

He says, "Our data clearly shows that there is an atypical fracture in the femoral shaft [thighbone]" and this strong link is conclusive. It is possible, but we can't prove it.

The New England Journal of Medicine publishes the research.

Aclasta and Aredia are all bisphosphonate drugs.

Osteoporosis drugs and fractures

Aspenberg reviewed the X-rays taken by the 12,777 patients with thighbone fractures. He discovered that the uncommon type of thighbone crack was present in 59 of these women.

Researchers also compared the rare fractures of 59 patients to 263 other people with more common thigh bone injuries. While 78% were treated with bisphosphonates for the uncommon fractures, only 10% of patients who had other fractures were.

Researchers then examined 1.5 million older women who had been registered in the National Swedish Patient Register in 2008, and found that they were at least 55 years old. The researchers then looked at 1.5 million women in the National Swedish Patient Register who were 55 or older in 2008. He divided the women who took the osteoporosis medications -- over 83,000 -- into different categories based on their use. These women took the drugs for less than one, one to 1.9, and two years.

The following are some other results:

Risk was affected by the amount of time used. The risk of an unusual fracture increased by 30% for every 100 days that bisphosphonate was used. Risks dropped quickly once the drug was discontinued. Since the drug was stopped, the risk of developing an unusual fracture fell by 70% each year. To prevent one rare fracture, the risk of occurrence was reduced by 70% for 2,000 women who had taken bisphosphonate drugs over a period of one year. Aspenberg claims that he received consulting fees from Eli Lilly, and Amgen grant support. These companies make osteoporosis medications. AddBIO is a stockholding company that develops a technique for implant-injection of bisphosphonate coated implants. The method is also patentable.

Aspenberg believes that short-term drug use is the best. WebMD tells him that the majority of patients should cease using it after five-years. Only women suffering from severe osteoporosis are allowed to continue. It is important to note that the medication should not be used unless there are indications.

A Second Opinion

Melvin Rosenwasser MD is a professor of orthopaedics at Columbia University College of Physicians and Surgeons. The research adds support to the long-suspected relationship between osteoporosis drugs and rare fractures.

He agreed that osteoporosis patients must reevaluate using the drugs after they have been on them for at least five years.

He says, "If you've been using the drug for more than five years you need to be tested." "Our research and other studies have proven that you must take the drug for at least five years in order to experience some side effects."

Rosenwasser's own research had shown that patients' bones strengthened after just three years. After five years of use, however, it was clear that the bone's structure had changed. WebMD tells him that "it doesn't necessarily mean broken."

He points out that the U.S. population is more diverse than Sweden. These findings might not be representative of what you would find in the U.S.

Joseph Lane MD is an orthopaedic specialist at the Hospital for Special Surgery - Weill Cornell Medical College. The study revealed that drugs can cause unusual fractures.

WebMD says he believes it "is not common" but that it "is a real entity".

Anybody taking drugs that causes thigh discomfort should inform their doctor. Lane works for Warner Chilcott and Novartis. They make osteoporosis medications.

FDA sent a warning out to all patients and providers of health about possible fractures among those who took bisphosphonates late in 2010.