May 21, 2012 — A new study published today in the Archives of Internal Medicine adds evidence to the growing body of scientific literature regarding the risk of femur fractures with long-term use of bisphosphonate osteoporosis drugs.
This drug class includes Actonel, Fosamax, and more. The study has found that long-term use of bisphosphonates increases the risk of atypical femur fractures. These femur fractures occur spontaneously, without injury to the leg.
The U.S. Food and Drug Administration (FDA) issued a warning in 2010 about the risk of femur fractures associated with bisphosphonates. However, the drugs remain widely used. Although many studies have found that the risk of femur fractures increases with longer duration of using the drugs, no one knows exactly how long the drugs are safe to use. Furthermore, no one knows how to identify high-risk patients.
The newest study adds evidence that atypical femur fractures are far more common than classic femur fractures. In fact, 82% of people in the study who had an atypical femur fracture had been treated with a bisphosphonate. Of the people who had classic femur fractures, just 6% had been treated with a bisphosphonate.
The study involved 477 Swiss patients who were at least 50 years old and had been admitted to the hospital with a femur fracture. There were 39 atypical femur fractures and 438 classic femur fractures. For comparison, the researchers used a control group of 200 people without femur fractures.
The lead researcher who authored the study, Dr. Raphael Meier, said:
“In conclusion, we have demonstrated that the association between bisphosphonate treatment and the occurrence of atypical fractures of the femur is highly likely and that the duration of such treatment significantly correlates with augmented risk.”
Despite evidence of the risks, Dr. Meier said that femur fractures are still rare, and the drugs’ benefits outweigh the risks. Indeed, the researchers compared bisphosphonate-users to non-users, and they found a 47% reduced risk of classic femur fractures in the bisphosphonate-user group. Most people take osteoporosis drugs to reduce the risk of bone fractures. Osteoporosis is a bone-thinning disorder that tends to develop with age, and increases the risk of bone fractures.
As the popularity of bisphosphonate drugs has increased, so have the number of side effects and the criticism against long-term use of the drugs. The FDA has recently called for more studies to identify risk-factors for femur fractures. Furthermore, studies need to be conducted to determine what is a “safe” amount of time to use the drugs.