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Bone Density and FRAX Testing

Posted Nov 21 2008 4:28pm

What Is FRAX?

Old way to be responsible: Ask your doctor about a bone density test. New way: Find a doctor who knows her FRAX -- and if you've never heard of it, you're not alone.


 

FRAX is not a miracle pill or a fancy piece of equipment. Unveiled by the World Health Organization in February, it is an elegant patient assessment formula that works in a risk-calculating computer program. And though not yet widely known, it is rocking the osteo-establishment, pulling focus away from bone density -- doctors' long-trusted yardstick for measuring the strength of the skeleton as it ages -- to spotlight what many experts believe is the overriding concern: determining a person's risk of actually breaking a bone (in other words, fracture risk assessment, or FRAX). That assessment matters to millions of people; in the United States, half of all postmenopausal women and a substantial number of older men will suffer a potentially life-altering fracture.


 

The revelation behind FRAX: Bone density is not the single best indicator in determining the risk of those fractures. It's still crucial, but a short list of other key factors, such as having a parent who broke a hip, is now also considered significant. "FRAX gives us the capacity to quantify these risk factors and look at how they interact with each other. For people with low bone mass, it's a far more rational and reasonable way to assess fracture risk," says Robert Lindsay, MD, one of the authors of a guide that the National Osteoporosis Foundation published in conjunction with the debut of the new formula. The upshot for women? FRAX, rather than bone density testing alone, is the best way to determine who needs treatment.


 

Both the guide and the FRAX formula are currently available to physicians. If your doctor is forward-thinking, she may already be using these tools; if she isn't, you may need to prod her a little. The best way to start is by asking about FRAX and the National Osteoporosis Foundation guidelines at your next ob-gyn or primary care appointment. Meantime, here's what you should know.


 

Lindsay and others hope that FRAX will help clear up the confusion that's existed since 1994, when the World Health Organization first announced criteria for diagnosing osteoporosis. Before then, the disease -- characterized by porous and fragile bones -- was typically diagnosed when an elderly woman showed up at the emergency room after breaking her hip or wrist. But by the mid-1990s, after-the-fact diagnosis was no longer good enough. A new class of drugs, bisphosphonates, which reduce fracture risk, was soon to be introduced. The medications, which include Fosamax and Actonel, were expensive and not without side effects, including slow healing, difficulty swallowing, inflammation of the esophagus, gastric ulcer and, in rare cases, increased possibility of infection after dental surgery. There has also been concern that long-term use of these drugs may result in an accumulation of older bone in the skeleton (because the drugs slow down the activity of scavenger cells, which clear away older bone to make room for new). Right now this is more a theory than a finding, but the thinking is that over time these drugs might make the skeleton more, not less, brittle.


 

The World Health Organization hinged its 1994 criteria on the one measure of bone health then available: the bone mineral density scan. The organization's rating system involved T-scores, which compared a postmenopausal Caucasian woman's bones with those of a 30-year-old. A T-score of -1 (one standard deviation below normal) and above was considered normal bone density; below -2.5 was considered osteoporosis; and any score between -2.5 and -1 was considered osteopenia, itself not a disease but an indicator of borderline low density. The lower the score, the thinking went, the more porous and fragile the bone -- and the greater the risk of breaking it. Therefore, women with low T-scores were more likely to be treated with medication.


 

Nearly 15 years later, however, experts disagree on who truly needs a prescription. There's no controversy surrounding women whose T-scores scream osteoporosis. But a far greater number of scores register in the gray area of osteopenia, and there has been no clear guidance regarding whether they should prompt treatment. "Some doctors will take a 55-year-old woman with a -1.5 T-score and put her on medication. Others will have a 75-year-old woman with the same score and leave her alone," says Ethel S. Siris, MD, of Columbia University and president of the National Osteoporosis Foundation.


 

The net result: A considerable number of younger postmenopausal women whose risk of fracturing a bone in the near future is statistically minuscule are being treated prematurely or unnecessarily. Nelson B. Watts, MD, of the University of Cincinnati Bone Health and Osteoporosis Center, says that if 30-year-old women submitted themselves en masse to the World Health Organization's measurement criteria, fully 16 percent would be diagnosed with osteopenia.


 

The other, perhaps more troubling, side of this story: Under the current parameters, many older people who face immediate grave risk of fracture aren't getting treatment, simply because their T-scores don't demand it. At Oregon Health & Science University, a 2005 study of women age 65 and older found that, based on the World Health Organization's bone density criteria, more than half of the women who suffered hip fractures did not technically have osteoporosis.


 

To learn more and take a risk assesment test go

http://www.shef.ac.uk/FRAX/tool.jsp?locationValue=9

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