For women who have received five years of bisphosphonate therapy, hip fracture risk does not differ with continuing treatment for an additional five years versus discontinuing treatment, according to a study published online Dec. 7 in JAMA Network Open.
Monika A. Izano, Ph.D., from Kaiser Permanente Northern California in Oakland, and colleagues examined the correlation of discontinuing bisphosphonates at study entry, discontinuing at two years, and continuing for five additional years with hip fracture risk among 29,685 women who had completed five years of bisphosphonate treatment at study entry.
The researchers identified 507 incident hip fractures. There were no differences in the cumulative incidence of hip fracture if women remained on therapy for two additional years or if they continued therapy for five additional years compared with bisphosphonate discontinuation at study entry (five-year risk difference, −2.2 [95 percent confidence interval, −20.3 to 15.9] per 1,000 individuals and 3.8 [95 percent confidence interval, −7.4 to 15.0] per 1,000 individuals, respectively). If women discontinued after two additional years, the interim hip fracture risk appeared lower (three-year risk difference, 2.8 [95 percent confidence interval, 1.3 to 4.3] per 1,000 individuals; four-year risk difference, 9.3 per 1,000 individuals [95 percent confidence interval, 6.3 to 12.3]).
“A potential benefit was suggested from continuing an additional two years, but the association of discontinuation at two years and other points with fracture risk should be further studied in randomized clinical trials,” the authors write..