Bisphosphonate Drug Holiday Increases Fracture Risk in Postmenopausal Women

Women with postmenopausal osteoporosis who took a bisphosphonate (BP) drug holiday have a higher risk for fractures, according to research presented at the annual World Congress on Osteoporosis, Osteoarthritis and Musculoskeletal Diseases in Florence, Italy.

A research team at the Université Lille Nord-de-France led a retrospective analysis to examine the likelihood of new clinical fractures in patients with osteoporosis who had taken a BP drug holiday vs patients who continued treatment after first-line BP therapy.

Researchers collected data from 898 patients with postmenopausal osteoporosis from 2008 to 2014, with 183 patients (mean age, 61.8 years) who had undergone BP treatment of alendronate (n=81), risedronate (n=73), zoledronic acid (n=20), and ibandronate (n=9), for 3 to 5 years.

Overall, 166 postmenopausal patients were included in follow-up ranging from 6 to 36 months: 31 patients in the drug holiday group and 135 patients in the continuous-treatment group.

Cox proportional hazards models were used to investigate the relationship between the drug holiday group and clinical fracture risk. Kaplan-Meier curves and log-rank tests were used to analyze survival rates without new clinical fractures.

The rate of new clinical fractures during follow-up was found to be 16.1% (5/31) in the BP drug holiday group compared with 11.9% (16/135) in the continuous treatment group.

The hazard ratio of new clinical fractures among the BP drug holiday patient group was 1.40 (95% CI, 1.12-1.60; P =.0095).

The risk factor of new clinical fractures for the whole study after first-line BP therapy was older age (71.2±7.1 years vs 65.7±8.4 years; P =.002).

“After first-line BP therapy in postmenopausal women with osteoporosis, the risk of new clinical fractures was 40% higher in subjects who took a bisphosphonate drug holiday,” the researchers concluded.

These results suggest that discontinuing BP therapy may have important implications on fracture risk in postmenopausal women.