WASHINGTON — Physicians and patients need to work together to decide for or against long-term bisphosphonate treatment for osteoporosis, said Dr. Sundeep Khosla at an international symposium sponsored by the National Osteoporosis Foundation
Alendronate is the longest-available bisphosphonate, with 10 years of follow-up data. In one analysis of 10 years of data for postmenopausal women on varying regimens of alendronate, those on 10 mg daily of alendronate had increased BMD for the spine and hip (N. Engl. J. Med. 2004;350:1189–99). Spine BMD increased by 14% from baseline over that period, and total hip BMD increased by 7%.
Smaller gains in BMD were noted for women on 5 mg daily of alendronate: 9% and 3% for the spine and total hip, respectively.
For women in the discontinuation group, spinal BMD leveled off (an increase of 0.3% from years 6–10) and total hip BMD declined slightly (a decrease of 1% from years 6–10).
This study “told us that alendronate did in fact have sustained effects over 10 years on bone density and bone turnover markers,” said Dr. Khosla, research chair of the division of endocrinology at the Mayo Clinic in Rochester, Minn. However, the fracture data were inconclusive.
In the FLEX (Fracture Intervention Trial [FIT] Long-Term Extension) study, published late last year, researchers assessed the effects of continuing or stopping alendronate after 5 years of treatment (JAMA 2006;296:2927–38).
For women on placebo for years 5–10, total hip BMD returned to baseline levels. Women on 5 mg/day or 10 mg/day of alendronate gained and maintained a 4% increase in hip BMD over baseline during the same period.
Women on placebo during years 5–10 had a slight increase in spine BMD, and women on alendronate had a steeper increase. Women who continued on alendronate for 10 years had an almost 50% reduction in clinical vertebral fractures, compared with those who stopped treatment after 5 years. There was no difference between the groups in terms of nonvertebral or morphometric vertebral fractures.
“Continuation of alendronate for 10 years maintains bone mass and reduces bone remodeling, compared with discontinuation after 5 years,” said Dr. Khosla.
Discontinuation did not increase the risk of nonvertebral fractures or x-ray-detected vertebral fractures, but the risk of clinically detected vertebral fractures was significantly increased in those who discontinued therapy after 5 years.
“For many women, stopping alendronate after 5 years for up to 5 more years does not significantly increase fracture risk, but women at high risk of vertebral fractures—such as those who already have a vertebral fracture or those [who might have] very low bone density—may benefit by continuing beyond 5 years.”