Women showed increased risk for hip fracture after discontinuing long-term bisphosphonate use

Jeffrey Curtis

SAN DIEGO — Women who discontinued use of bisphosphates for more than 2 years after long-term use were up to 39% more likely to have hip fractures compared to those who continued treatment, according to findings presented at the American College of Rheumatology Annual Meeting.

Although treatment with bisphosphonates may slow bone loss and decrease fracture risk in patients osteoporosis, according to a press release from the ACR, some patients are stopping its use temporarily or permanently (known as a drug holiday) after years of continuous therapy given FDA warnings of the long-term risks. The benefits and risks of stopping bisphosphonates, and the correct time to restart treatment, remains uncertain.

“Our goal was to evaluate the risk of discontinuing therapy based on the length of the holiday, controlling for any possibly cofounding factors, such as race, median income, rural or urban location or comorbidities,” Jeffrey Curtis, MD, MS, MPH, William J. Koopman endowed professor of rheumatology and immunology at the University of Alabama at Birmingham, said in the release.

Researchers performed a population-based cohort study to determine the potential impact of discontinuing bisphosphonates on hip fracture risk among women after long-term (3 to 5 years) continuous therapy. Using Medicare data from 2006 to 2014, they identified 156,236 women who were adherent to bisphosphonates for 3 or more years and did not use other bone therapies. Investigators calculated rates of hip fracture for continuing therapy and among those who stopped, for categories of since discontinuing, then evaluated the risk of discontinuing per the length of holiday.

During a follow-up period of 2 years, 40.1% of women discontinued using bisphosphonate treatment for at least 6 months or more and 12.7% subsequently restarted a bisphosphonate. In total, 3,745 hip fractures occurred during follow-up. Women who continued bisphosphonates and gradually increased as the length of the drug holiday increase had the lowest rate of hip fractures; however, women who discontinued use for more than 2 years had the highest rate of hip fractures and were associated with an increased risk for fracture of up to 39% compared to those who continued bisphosphonate use. The most common bisphosphonates were alendronate and zoledronic acid.

“While the notion of a drug holiday has become commonplace in osteoporosis management, there’s a dearth of evidence on when we should consider restarting bisphosphonate therapy,” Curtis said in the release. “The study’s findings may provide useful evidence to help guide rheumatologists as they plan long-term therapy for their patients dealing with low bone mass.” – by Savannah Demko

Reference:
Curtis J, et al. Abstract 828. Presented at: American College of Rheumatology Annual Meeting; Nov. 3-8, 2017; San Diego.

Disclosures: Curtis reports support from AbbVie, Roche/Genentech, BMS, UCB, Myraid, Eli Lilly, Amgen, Janssen, Pfizer, Corrona and Crescendo Bio. Please see the full study for a complete list of all other authors’ relevant financial disclosures.