Bisphosphonates: forever or 5 years and stop?

Evidence • FLEX1: An RCT of 1099 postmenopausal women with osteoporosis (mean age 73, 60% with previous fracture, 4to 5-year use of alendronate) randomized to 5 mg or 10 mg of alendronate or placebo. After 5 additional years, bone mineral density (BMD) scores in the placebo group were lower than in the alendronate group, and total nonvertebral fractures and total vertebral fractures were not statistically different. -In the total clinical vertebral fracture subgroup, alendronate statistically significantly lowered fractures (2.4% vs 5.3% with placebo). Number needed to treat is 36 for continuing alendronate. -Although patients with lower BMD or previous fracture had a higher risk of fractures, there was no statistically significant benefit seen in these subgroups. • HORIZON-PFT2: An RCT of 1233 patients randomized to stop or continue zoledronic acid for 3 years (after 3 years of therapy) also found no difference in clinical fractures.