RENEE MONTAGNE, HOST:
Here's another story about a common medical test that may not need to be so common. To diagnose osteoporosis, doctors often do bone scans every two years on older women. Osteoporosis causes painful spine fractures and broken hips that are often fatal. And it's a big problem for women past menopause. Now a new study shows many women can wait as long as 15 years between bone scans. NPR's Richard Knox has the story.
RICHARD KNOX, BYLINE: Around 15 years ago, many doctors started doing bone scans to see if older women should start taking a drug to prevent bone loss. The test was heavily promoted by a drug manufacturer.
DR. CLIFF ROSEN: That notion, though, really didn't come from anything scientific.
KNOX: That's Dr. Cliff Rosen, a bone specialist at Maine Medical Center in Portland.
ROSEN: It came from this concept that, well, after two years we should see if there's change in bone density and if that is going to predict fractures. So that became the norm.
KNOX: In 1997, Congress passed a law requiring Medicare to pay for bone scans every two years. Now research at the University of North Carolina shows for a substantial fraction of older women, perhaps as many as half, such frequent bone scans are not necessary. The study shows that women who get a bone scan at 67 that's normal, or shows just a little bone-thinning, can safely wait 15 years before they get another one.
DR. MARGARET GOURLAY: Ten percent of those women developed osteoporosis over about 15 years.
KNOX: That's Dr. Margaret Gourlay. She led the study, which is in the New England Journal of Medicine. By contrast, some women whose first bone scan showed moderate bone loss went on to develop osteoporosis much sooner, within five years. And some with more pronounced bone loss were only a year away from osteoporosis and high risk of fracture. Gourlay says the difference between the two low-risk groups and the two high-risk groups was surprising.
GOURLAY: What we didn't expect was that the upper two groups would take such a long time to develop osteoporosis. We knew that there would be a difference. We didn't expect that much of a difference.
KNOX: The implications could be big. Rosen says the study should be very reassuring to many post-menopausal women worried about osteoporosis, because half of the 5,000 women in the study were at low risk of developing the disease.
ROSEN: And I think that's the take-home message. Not everybody as they age is going to develop osteoporosis. So we need to find out who are those individuals that are at high risk because they're older but may not be at that much greater risk.
KNOX: He also thinks the study could result in many fewer bone scans and maybe fewer women on osteoporosis drugs.
ROSEN: I think it's going to go way down. And maybe it should, because we tend to over-treat, I think.
KNOX: But Gourlay is more cautious.
GOURLAY: I think the main thing that it will do is not drastically cut down the number of bone density tests. We're hoping the first step is that people will just think about the bone density test, and that the patients will ask for the first test more often.
KNOX: She points out that only 13 percent of women on Medicare get a bone density test. That suggests millions aren't getting an initial baseline scan that would tell them whether they're at risk of osteoporosis or not, even as millions of others are getting more scans than they need.
By the way, the new study doesn't provide any guidance for women under 67. Many of them are getting regular bone scans too. But they'll have to wait for another study.
Richard Knox, NPR News.
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