Bisphosphonates Associated with Increased Risk of Atypical Hip Fractures, Researcher Says

The use of bisphosphonates, drugs prescribed to prevent hip fractures in women with osteoporosis, is associated with an increased risk of atypical fractures in this joint.

The research is contained in a PhD thesis by Javier Gorricho-Mendívil, at the NUP/UPNA-Public University of Navarre (Spain), MedicalXpress reports.

“Hip fracture is the most common cause of admittance to hospital in the traumatology and orthopaedics departments,” according to the author. He says, “fractures are associated with a high rate of mortality and loss of quality of life together with significant costs.” In the European Union in 2010, there were 620,000 hip fractures and the cost associated with the fractures amounted to more than 37,000 million euros.

Most hip fractures occur in people over 65 and they are more frequent in women. “In Spain the population over 65 has increased considerably in recent years rising from 14.92% in 1997 to 16.62% in 2008,” Gorricho-Mendívil wrote. He said the average age of women who suffer hip fractures is over 80 and with fracture rates among those over 85 in excess of 20 per 1,000 inhabitants per year.

Bisphosphonates—Fosamax is the most familiar brand name—are the drugs most frequently prescribed to treat osteoporosis, but in recent years European, American, and Spanish drug regulators have issued “various warnings owing to the correlation detected between the use of these drugs and various problems linked to correct bone regeneration: osteonecrosis of the jaw and atypical hip fractures.” Recently, doctors were asked to review treatment after five years to determine whether it was appropriate to continue pharmacological treatment, according to MedicalXpress.

Oral bisphosphonates “have been consistently found to increase the levels of bone mineral density, and reduce vertebral fractures detected in X-rays,” according to Gorricho-Mendívil. In trials using a placebo in which there was a proportion of the target sample not taking any medication, the reduction in the number of hip fractures was much smaller, according to Gorricho-Mendívil. His thesis supervisor is Juan Erviti-López, a researcher at Navarrabiomed-Fundación Miguel Servet.

Gorricho-Mendívil focused his thesis research on Spain. He used the Database for Pharmaco-epidemiological Research in Primary Healthcare (BIFAP), with 4.8 million clinical records of the National Healthcare Service of Spain provided by over 18,000 doctors. This signifies nearly 25 million people at one-year follow up. Records were rendered anonymous so that researchers could not identify the patients. The database is designed and managed by the Spanish Agency for Drugs and Healthcare Products (AEMPS).

The study was supported by a grant from the Spanish Ministry of Health, Social Services and Equality in 2009 and includes hip fractures in women over 65 from 2005 to 2008. Gorricho-Mendívil identified 2,009 women, average age, 82,with typical hip fractures and 44 with atypical fractures, those that occur in a less frequent location.

The author concludes that the use of oral bisphosphonates was not associated with a reduction in hip fractures in women over 65 but it was associated with a greater risk of atypical hip fractures (subtrochanteric or diaphyseal fractures). “This risk increases when the time exposed to bisphosphonates is increased. The longer the treatment time was, the greater the risk of atypical fracture,” Gorricho-Mendívil says in summary.

Gorricho-Mendívil and Erviti-López, along with Scandinavian and Canadian researchers, published an article about the research in the BMJ.