Twelve years ago, a Boston Globe story raised doubts some Canadian researcher had about bone scans for the diagnosis of osteoporosis. It was a scary story to write. Doctors, some patient advocacy groups, researchers and drug makers were enthusiastic about the new-found ability to measure bone density and the development of bisphosphonates like Fosamax to treat it. Osteoporosis was under-treated, they said. Still, it seemed the concerns needed to be explored.
Now comes this from the FDA, which rarely uses The New England Journal of Medicine as a forum .
The long-term safety and efficacy of bisphosphonate therapy for osteoporosis are important concerns for the Food and Drug Administration (FDA). In response to postmarketing reports of rare but serious adverse events associated with bisphosphonates, such as atypical femur fractures, osteonecrosis of the jaw, and esophageal cancer, the FDA performed a systematic review of long-term bisphosphonate efficacy. The findings, summarized here, were presented at a joint meeting of the FDA Advisory Committee for Reproductive Health Drugs and the Drug Safety and Risk Management Committee.1 The committees jointly recommended that bisphosphonate labeling be updated, although there was consensus that the data did not support a regulatory restriction on the duration of drug use.
In an unusual move that may prompt millions of women to rethink their use of popular bone-building drugs, the Food and Drug Administration published an analysis that suggested caution about long-term use of the drugs, but fell short of issuing specific recommendations.
Specialists differ on the value of tests for bone density
By Tinker Ready Globe Correspondent 4//25/00
When Winchester gynecologist Robert Shirley does an ultrasound bone scan of a patient’s heel, the news he delivers is often less than comforting. Based on the heel scan, which measures bone density in the foot, Dr. Shirley diagnoses 1 in 3 of his older patients with either osteoporosis or osteopenia, the bone-thinning disease that is common in aging women and
also affects some older men.
“It’s a very helpful tool to make them realize that osteoporosis is real, and they need to think about it,” said Shirley.
Certainly, few women will fail to take notice when they hear they have a disease that may lead to brittle bones, a hunched back or “Dowager’s hump,” and painful, disabling fractures. As frightening as the diagnosis sounds, however, it does not always lead to serious fractures _ the most severe of which is hip fracture _ and the bone scan itself cannot accurately predict who will get hip fractures, or even fully measure bone strength. Still, osteoporosis is now defined by bone density, even though density only accounts for about 70 percent of bone strength. Other factors _ such as the actual shape, structure and size of a bone, and the presence of tiny cracks know as “microdamage” _ seem to factor in as well. But these things are not measured by bone scans. And, when it comes to hip fractures and the elderly, a person’s risk of falling seems to play as much of a role in fracture risk as does bone density.
So, when a group of scientists convened by the National Institutes of Health met for three days in late March to review the most current data on the diagnosis and treatment of osteoporosis, they declined to endorse the bone scan as a screening test for osteoporosis. In its March 29 consensus statement, the panel noted that the risks for osteoporosis _ as reflected by low bone density _ and the risks for fracture, overlap but are not identical.
In addition, the panel expressed concern that different bone scanning devices and techniques produce conflicting results. A committee of scientists is working on a plan to standardize the tests, but right now, an ultrasound bone scan of the heel might indicate osteoporosis, while an x-ray scan of the spine may not. And even though bone loss can accelerate at menopause, tests in women under the age of 60 are particularly weak at predicting hip fractures.
“There are other things outside of bone density that we may want to measure to better improve our prediction of fracture risk,” Mary Bouxsein, an instructor in the Orthopedic Biomechanics Laboratory at Beth Israel Deaconess Medical Center told the panel.
This is in stark contrast to what many doctors and advocacy groups say about bone scans and osteoporosis. Many see the disease as a silent epidemic that goes undiagnosed in millions of women. The National Osteoporosis Foundation cites an alarming list of statistics to drive that point home: 28 million people either have the disease or are at risk, and half of all women will suffer a fracture of the spine, hip or wrist during their lifetime.
The group recommends bone scan screening for all women over 65, has lobbied Medicare to cover the test, and is now pushing for mandatory private insurance coverage.
Bone scans are not perfect, but they are the best tool available to identify women with the disease, said Conrad Johnston, director of the Bone Studies Laboratory at Indiana University, who is the current president of the National Osteoporosis Foundation.
“Everybody who has high cholesterol doesn’t have a heart attack, and everyone who has low bone mass doesn’t have a fracture. But for many women, he said, “low bone density is the single best predictor of who will fracture.”
So should women just ignore this? The pharmaceutical industry certainly isn’t. The makers of bone building drugs are active in promoting bone scans. Merck, which makes Fosamax, recently ran ads in magazines like Good Housekeeping and Parade encouraging healthy women to seek testing. Warning that undiagnosed osteoporosis can lead to broken bones or the disfiguring Dowager’s hump, the ad equates the simple, painless bone density test with mammography to detect breast cancer.
Osteoporosis is serious business for many who have it. According to the National Osteoporosis Foundation, the disease causes 1.5 million fractures annually, about half of them in the spine. Spinal fractures can cause a range of symptoms; some people may feel nothing at all, others may have back pain, and yet others may develop the Dowager’s hump. The scientific data on the incidence and severity of spinal fractures is incomplete. But, all agree that the hip fracture, which strikes about 300,000 people per year in their 70s and 80s, can be a devastating and sometimes deadly event. About 30 percent of older people who fall and break a hip end up in a nursing home. Bone density contributes to hip fractures, but so does a long list of other factors including age, low body weight, smoking, mobility, exercise habits, and poor eyesight, which can make someone more vulnerable to falls, says Dr. Arminee Kazanjian, the director of the British Columbia Office of Health Technology Assessment.
After reviewing years of research into bone mass and fracture, her agency released on of the most scathing critiques on the use of bone scans. It concluded that as many as 70 percent of the women who eventually break a hip will not be diagnosed at menopause with osteoporosis, if that diagnosis is based on a bone scan alone. And, only half of the 30 percent of women identified as having osteoporosis or osteopenia will go on to have a fracture.
“The important health outcome is bone fracture,” said Kazanjian. “Bone mineral density is a minor factor. Any other combination of factors is much more important.” Rather than rely on the bone scans alone to diagnose osteoporosis, Kazanjiam and others suggest that doctors focus on the other factors that contribute to fracture risk. For example, a woman with low bone density, but who doesn’t smoke (which contributes to thinning bones) and has good eyesight, may be less likely to break a hip than a woman with high bone density who uses a walker and has a family history of fractures, she said.
Amy Allina of the National Women’s Health Network, a Washington, D.C.-based advocacy group, says that women who are told they don’t have osteoporosis based on a bone scan alone may not take steps to prevent the falls that cause hip fractures, even though they may be at risk. And those whose bone scans indicate that they have osteoporosis may spend years on medication, even though they may never have broken a bone.
That’s a problem, Allina said, because the treatments for osteoporosis themselves come with risks. Hormone replacement therapy, which millions of women take to both treat and prevent osteoporosis, can increase a woman’s odds of developing breast cancer. And Fosamax, a non-hormone drug that builds bone, irritates the throat and its long-term effects are unknown.
A 1993 decision by a World Health Organization panel set the stage for the bone scan to inadvertently become a routine diagnostic test for osteoporosis. The panel established a scale _ based on the average bone density of a premenopausal woman _ that allows doctors to measure bone loss, diagnose osteoporosis, and establish fracture risk. The average 55-year-old woman has a 15 percent chance of breaking her hip someday. If her bone density is 1 point below the WHO average, she is defined as having osteopenia, a level of bone thinning that increases the lifetime risk of hip fracture by 20 to 45 percent. Osteoporosis is diagnosed when bone density falls 2.5 points below the WHO average. This, by some measures, raises the risk of hip fracture to greater than 45 percent. Brigham and Women’s Hospital in Boston recently produced a detailed set of osteoporosis diagnosis and treatment guidelines for its patients and doctors. The guidelines don’t endorse bone scans to be used as screening tools alone, but they advise doctors to recommend bone scans to all women over the age of 65.
Dr. Robert Barbieri, chairman of the Department of Obstetrics and Gynecology at Brigham and Women’s, sees the bone scan as a useful tool but he emphasized that a diagnosis of osteoporosis should not be based on the test alone. He says he is confident that doctors are considering other factors when assessing a patient’s bone strength and risk of a fracture.
“They use history and physical exams and laboratory tests in an integrative way and pull them all together,” he said.
But Mark Hefland, a researcher at the Oregon Health Sciences University, told the NIH pane that doctors are relying too heavily on bone scans, even though many of them admit that they don’t understand how bone scan scores relate to fracture risk.
“However we may like it, this is how diagnosis is occurring in everyday practice,” said Hefland, the director of the school’s Evidence-Based Practice Center.
Dr. Shirley of Winchester says he relies on bone scans to diagnose osteoporosis, but said that he also spends a lot of time with patients talking about fracture risk and alternatives to drug therapy like increasing weight-bearing exercise and boosting calcium intake. But according to Diane Saparoff, who runs a monthly support group for women with osteoporosis at the Jenks Senior Center in Winchester, Dr. Shirley’s approach differs greatly from that of other doctors.
“Many of the doctors order these tests but there is no follow up,” she said. The
doctors often don’t explain the test scores or help women come up with a fracture prevention plan, she said. “They just throw Fosamax at them.”
Dr. Johnston of the National Osteoporosis Foundation acknowledges that some doctors may be relying too much on bone scans to diagnose
osteoporosis. “I think that’s probably happening but it shouldn’t be,” he said. “This is a reasonably new area. Bone mineral measurements have only been around for about 10 years. Its takes a while for people to get up speed.”
Report lists ways to avoid injuries
A recent report from the National Institutes of Health offers advice on how to build and maintain strong bones:
*Get adequate calcium and vitamin D both early in life and throughout adulthood.
* Engage in regular exercise; it contributes to the development of peak bone mass and may reduce the risk of falls in older individuals.
*As needed, use drugs that enhance bone mass; medications have been been shown to reduce the risk of osteoporotic fractures.
In addition to regular exercise, there are several steps seniors can take to avoid falls, according to the National Center for Injury Prevention and Control:
* Use non-slip rugs and bath mats. Put grab bars in the bathroom and handrails on the stairs.
* Ask your doctor to review medicines that may cause drowsiness or
confusion when combined with others you may be taking.
*Stay current with eye exams.
–Tinker Ready
This story ran on page D01 of the Boston Globe on 4/25/2000.
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