Monday, April 27, 2015
Bone-Building Drug Strengthened Hips, Spines of Frail Women in Study
But greater bone density did not translate into fewer fractures among these high-risk women, who were living in nursing homes and assisted living facilities during the study, the researchers added.
“Two surprising findings emerged,” said study author Dr. Susan Greenspan, a professor of medicine at the University of Pittsburg.
The drug improved bone strength in the very old and frail as well as it did in younger and more robust seniors, but there was no association between increasing bone density and reducing fractures, she said.
“We first wanted to see if frail elders could even tolerate such treatment and whether it would improve bone density. However, we had expected to see a positive trend of fewer fractures. But if anything, there were more fractures in the treatment group,” Greenspan said, although “that could well be just a chance finding.”
The study was published online April 13 in the journal JAMA Internal Medicine.
Fracture in the elderly occur not only because the bones are weak, but also because people in this group are prone to falls writes Dr. Robert Lindsay, chief of the Osteoporosis Center at Helen Hayes Hospital in West Haverstraw, N.Y. in an accompanying editorial. “Both risks are high in this population. The study tells us that treating one side of the equation, bad bones, can only do so much when the risk of injury is high, because the patients studied were quite frail.”
The cost of the drug can be anywhere from $5,800 to $7,000, depending on where it is given (hospital or clinic) and what insurance is covering the drug.
For the study, Greenspan and her colleagues assigned 181 women with osteoporosis, aged 65 and older, to a single infusion of Reclast or a placebo. All of the women were given vitamin D and calcium supplements. Some of the seniors also suffered from metal impairment, immobility and other medical conditions, the researchers noted.
After a year and again after two years, the researchers measured the women’s bone density at their hip and spine. They also tracked any falls or other adverse events.
The women given the Reclast saw bone density at the hip increase an average of 2.8% after a year, compared with a slight reduction in bone density among women given the placebo. At two years, bone density increased 2.6% among women given the drug, but decreased 1.5% among those given the placebo.
Bone density does not equal bone strength. Reclast is a biophosphonate. It increases the density of bone by preventing the osteoclasts from dismantling old bone. However, is also prevents the osteoblasts from building new bone. This process is called remodeling and is constantly at work in our bodies. The drug makes the density study better by maintaining old brittle bone, filled with calcium, but devoid of collagen. Therefore, it has little strength and the rate of fractures increases.
The Bottom Line:
The study suggests what has been apparent for years – researchers need to rethink the approach to fracture prevention. As a patient, so do you.
April 13, 2015 National Institutes of Health