Osteoporosis Experts Discuss Bisphosphonate Holidays

“We ask them to continue their healthy lifestyle habits. Exercise, especially to improve strength and balance, is very important, because this reduces the risk of falling.” Dr. Hansen counsels patients to consume adequate calcium, vitamin D and protein, and to avoid tobacco and excess alcohol. “We also ask patients to contact us if they have a clinical fracture or any evidence of a silent compression fracture, such as sudden height loss.”

Patients on a drug holiday should have periodic dual X-ray absorptiometry (DXA) to watch for bone density declines that indicate increased fracture risk, Dr. Hansen said. Obtaining a baseline total hip T-score as their holidays begin may guide clinicians on how often to scan, according to recent data that suggested patients with higher scores may not need another bone density scan for five years.⁸

Atypical Femur Fractures

Elizabeth Shane, MD, professor of medicine at Columbia University’s College of Physicians and Surgeons, New York City, discussed atypical femur fractures (AFFs), which—along with osteonecrosis of the jaw—are a rare but serious possible adverse event associated with bisphosphonates that cause alarm and a drop in prescriptions.

Dr. Shane

“A portion of this decline may be appropriate, relative to the precise targeting of people who may be at greater fracture risk or when it comes to initiating drug holidays,” said Dr. Shane, who expressed concern that both media reports and U.S. Food & Drug Administration safety warnings about atypical femur fractures caused patients to avoid therapy that not only reduces hip fractures but saves lives, she said. ^9,10

Ordinary femoral neck and intertrochanteric hip fractures account for up to 95% of hip fractures in elderly patients, and atypical femur fractures are only a small subset and account for less than five of every 1,000 hip fractures.¹¹

On imaging, AFFs are more horizontal and have much thicker cortices than other hip fractures, Dr. Shane said. In 2014, the ASBMR revised its definition of AFFs; four out of five features are now required for diagnosis:¹²

• Minimal or no trauma;
• Fracture line originates at the lateral cortex, is substantially transverse in orientation and may become oblique as it progresses medially;
• Non-comminuted or minimally comminuted fracture;
• Complete fractures extend through both cortices and may be associated with a medial spike; incomplete fractures involve only the lateral cortex; and
• Localized periosteal or endosteal thickening of the lateral cortex at the fracture site, also called beaking or flaring.

Atypical femur fractures also tend to cause prodromal pain in the groin or thigh in 70% of patients, unlike other hip fractures, and about 26% of patients are slow to heal. Although bilaterality is seen in only 28% of patients with AFFs, up to 60% have radiographic changes on their other side.¹³