A long-term study of the most widely used osteoporosis drug has found that many women can discontinue the drug after five years without increasing their fracture risk for as long as five more years.
The study on alendronate was led by researchers at the University of California, San Francisco. The research also showed that women at very high risk of painful spine fractures might be better-off continuing treatment.
"This has important implications as it has not been known whether treatment of osteoporosis should be continued indefinitely," said lead author Dennis Black, PhD, professor in the UCSF Department of Epidemiology and Biostatistics. "Because women with osteoporosis, particularly older post-menopausal women, often need to take multiple drugs, this would be welcome news for this group."
According to Black, shorter term studies of up to five years duration have shown reductions in fracture risk with alendronate treatment. This was the first study to examine the effects on fracture using the drug longer than five years, he said.
"We found that women who discontinued the drug had the same rate of non-spine fractures as women who continued using the drug," he said. "However, for clinically-recognized spine fractures, usually discovered due to back pain, continuing alendronate was better than discontinuing. And, if women choose to continue, we showed that 10 years of treatment is safe."
The new findings are from a follow-up study to the initial randomized trial that examined the effect of daily alendronate, a bisphosphonate or anti-resorptive drug, on bone mineral density and fracture risk in post-menopausal women with low BMD for up to 3.8 years.
Alendronate is used to reduce bone loss, increase bone density and reduce the risk of spine, wrist and hip fractures in postmenopausal women. Bisphosphonates are the most commonly used treatment for postmenopausal osteoporosis.
The initial study was named the Fracture Intervention Trial or FIT, and its results were reported in 1996 and 1998.
The follow-up study now being reported is known as FLEX, for FIT Long-Term Extension. It was designed to evaluate the effects on BMD for a total of 10 years, comparing those who continued to take the drug with those who stopped after five years. A total of 1,099 women who had previously received alendronate in FIT and afterwards, were re-randomized to receive placebo or alendronate at 5 mg or 10 mg daily.
According to Black, findings showed that "women randomized to continue taking alendronate did maintain a higher BMD at the hip and spine than those randomized to placebo. For those who stopped, there was a modest loss of BMD, but not a dramatic loss."
The study found differences in bone loss in those who continued versus those who stopped but the differences were surprisingly modest and there were no differences in rates of non-spine fractures or in spine fractures as assessed by comparison of spine x-rays. Severe spine fractures associated with painful symptoms were lower in those who continued but were relatively rare overall (5 percent in those who discontinued vs. 2.5 percent among those who continued drug treatment).
In the United States, osteoporosis affects about 44 million people age 50 and older, and of these, 80 percent are postmenopausal women.
According to Black, "Older people are often taking several different medications. But for many women, if they can discontinue one treatment after five years, it would also be a welcome lifestyle change and will decrease their overall costs for medical care."
A typical regimen requires the patient to drink a full glass of water with the drug on an empty stomach and sit upright for up to 30 minutes.
While the results suggest discontinuation of the treatment for some women, women at a very high risk of clinical spine fractures may benefit by continuing beyond five years, according to Black.
"In the future, we hope to be able to more specifically identify people who should continue and who should stop."