Atypical Fractures Rise With Bisphosphonate Use
In another talk at the meeting, John Wang, Ph.D., a statistician at the National Institute of Arthritis and Musculoskeletal and Skin Diseases, presented additional data documenting the relative risks of atypical and typical fractures with bisphosphonate treatment.
Patients taking a bisphosphonate face a risk of about 1 additional subtrochanteric hip fracture for every 100 typical hip fractures prevented, according to an analysis of national data during 1996–2007. The new data present no direct evidence for a role of bisphosphonate use in causing subtrochanteric hip fractures, which along with femoral shaft fractures constitute the “atypical” category. But the temporal link between the steady increase in bisphosphonate use among elderly American women during 1996–2007 and the concurrent rise in subtrochanteric fractures also in elderly American women strongly suggests that a causal link exists, Dr. Wang said.
He analyzed data on U.S. subtrochanteric fracture rates from the Nationwide Inpatient Sample from 1996 to 2007, along with data on U.S. bisphosphonate use from the Medical Expenditure Panel Survey. The analysis suggested that bisphosphonate use led to one subtrochanteric fracture for every 100 typical hip fractures prevented, Dr. Wang said, which was similar to the relationship in Dr. Ott's data.
“We have shown a temporal relationship; one precedes the other,” Dr. Wang said in an interview. “That is the first step in showing a causal relationship.” Proof would require a prospective study of atypical fracture incidence in highly compliant patients, he said.
Dr. John Wang discusses data on subtrochanteric femoral fractures in an interview at
Source Mitchel L. Zoler/Elsevier Global Medical Newswww.rheumatologynews.com
Recommended Steps to Minimize Risk
Despite substantial evidence linking long-term bisphosphonate use and an increased rate of atypical femur fractures, bisphosphonates remain an effective and attractive drug class for treating osteoporosis.
The task force assembled by the ASBMR recommended several steps for physicians to take when they prescribe a bisphosphonate to reduce atypical fracture risk.
Patients with a low absolute fracture risk should not receive a bisphosphonate, said Dr. Peter R. Ebeling, a task force member, summarizing the group's recommendations at the meeting.
Patients with secondary causes of rapid bone loss may not need long-term bisphosphonate treatment. Continued use beyond 5 years should be evaluated annually, said Dr. Ebeling of the University of Melbourne.
Patients without a recent fracture and with a femoral neck T score of more than −2.5 after 5 years of continuous bisphosphonate treatment should receive consideration for a drug holiday. Patients taken off bisphosphonate treatment should undergo an annual assessment of their clinical status, markers of bone turnover, bone density, and their fracture risk.
Because a majority of patients who developed an atypical fracture on bisphosphonate treatment had prodromal pain in their thigh or groin, physicians should alert patients to watch for and promptly report such pain. When suspicious pain occurs, the patient needs “urgent” radiographic assessment of both femora, even for unilateral pain, Dr. Ebeling said. If the radiographs appear normal, perform a follow-up examination by MRI or radionuclide scintigraphy scanning.
If a patient has a fracture while on a bisphosphonate, treatment with the bisphosphonate or any other potent antiresorptive drug should stop. At that time, assess the patient's calcium and vitamin D status and prescribe adequate supplementation if needed. The physician should consider prescribing teriparatide to improve fracture healing, particularly if it appears that the fracture has not healed by 4–6 weeks following surgical repair.
Dr. Ebeling has served as a speaker for Merck & Co., Eli Lilly, Novartis, and Sanofi-Aventis; been on advisory boards for and received research grants from Merck, Amgen, and Novartis; and received educational grants from Amgen, Eli Lilly, and Sanofi-Aventis.
Physicians should alert patients to watch for and promptly report prodromal pain in their thigh or groin.
Source DR. EBELING
