Tool offers improved method for calculating fracture risks
■ Many people with low bone mass will never have a fracture, but some will. The FRAX algorithm helps to pinpoint who needs to be treated.
By Susan J. Landers — Posted March 17, 2008
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Washington -- Physicians now can take advantage of new tools that go beyond bone density scores to help assess the fracture risk faced by older patients with low bone mass.
FRAX, an algorithm developed by the World Health Organization to calculate an individual's 10-year risk of fracture, was released Feb. 21, as was a new clinician's guide for the prevention and treatment of osteoporosis, that incorporates the algorithm. The guide was developed by the National Osteoporosis Foundation in collaboration with the American Assn. of Clinical Endocrinologists, the American College of Radiology, the American Orthopaedic Assn. and the International Society for Physical Medicine and Rehabilitation.
About 10 million people in the U.S. have osteoporosis, which is generally diagnosed by a low-impact fracture or a bone density score of minus 2.5 as measured by dual-energy x-ray absorptiometry, or DXA scan. It is clear this group needs to be treated with one of the several pharmaceutical products approved to strengthen bones.
But for another 34 million people, questions about treatment needs have presented more of a puzzle. These are the people whose bone density scores range between minus 1.0 and minus 2.5. They are often said to have osteopenia. Many in this group also may be at risk for fractures, but it has never been clear just how great that risk is and who among them is most in need of treatment. The new tools were developed with this population in mind.
"Until now, we have had no way to determine which osteopenic patient is at low risk [for a fracture] and which is at high risk," said Ethel Siris, MD, professor of clinical medicine at the Columbia University College of Physicians and Surgeons in New York City. Dr. Siris is also the president of the osteoporosis foundation.
One in two women and one in four men older than 50 will have an osteoporosis-related fracture, according to the National Institutes of Health. The cost of such fractures is enormous, with a price tag for the health care system of about $14 billion each year. The fractures also can lead to years of disability and often death for individuals. Many groups, including the AMA, have worked to improve educational efforts on ways to prevent bone loss and to gain insurance coverage for bone density screening for those at high risk.
The new clinician's guide provides evidence-based direction to help physicians and others identify patients older than 50 who are at risk of breaking a bone, Dr. Siris said. "Internists have used the notion of risk assessment for some time now in terms of looking at cardiovascular risk, breast cancer risk, and we are delighted that now we have the capacity to look at absolute fracture risk in a much more evidence-based and meaningful way than before."
The recommendations "represent a significant improvement in the quality of risk assessment and treatment of osteoporosis and will assist clinicians in managing osteoporosis," said Richard Hellman, MD, president of the American Assn. of Clinical Endocrinologists, in a statement.
The new guide and algorithm also shift the focus from bone density scores to fracture risk. "We are emphasizing fractures because they are the clinical end point. Who would care if no one fractured?" asked Robert Lindsay, MD, PhD, chief of internal medicine at Helen Hayes Hospital in New York City. He also was an author of the guide.
This change was applauded by Laura Tosi, MD, an orthopedic surgeon at Children's National Medical Center in Washington, D.C. "Now the focus is on fractures, not on osteoporosis. Far more people who don't have osteoporosis will fracture. Fractures are the issue," stressed Dr. Tosi, who also served on a multispecialty group that worked on the new guide.
Clinicians and researchers have known for several years that FRAX was being developed by John A. Kanis, MD, professor emeritus at the University of Sheffield in the U.K., and his colleagues. Dr. Kanis also is the director of the WHO Collaborating Centre for Metabolic Bone Diseases at the university.
Edward Leib, MD, professor of medicine at the University of Vermont and director of the osteoporosis center at Fletcher Allen Health Care in Burlington, said he began calculating 10-year fracture risk about five years ago using early data published by Dr. Kanis.
FRAX was designed as an online calculator into which physicians provide answers to questions about a patient's height, weight, measure of bone density at the hip, history of fracture, smoking status, whether a parent had fractured a hip, and how many drinks per day are imbibed. The calculator then determines the patient's risk of fracture over the next 10 years.
The calculator can be adjusted for use in several countries, including nations where DXA scanners are unavailable. The resulting score can be used to determine whether treatment is cost-effective.
In a separate analysis performed by the osteoporosis foundation, it was found to be cost-effective to treat a person in the United States when the 10-year risk of a hip fracture reached about 3% as determined by FRAX. It was also considered cost-effective to treat when the risk for any fracture over the next 10 years reached 20%.
"That is not to say that you should not treat anyone else," Dr. Siris said. "But above those thresholds, it is cost-effective and medically proper to treat."
The new guide also breaks new ground by including men older than 50 and postmenopausal African-American, Asian and Latina women for the first time as populations in need of assessment for fracture risk. Recent research has found significant risk for low bone mass in people of all ethnic backgrounds. For example, when compared with other ethnic and racial groups, risk is increasing most rapidly among Hispanic women, according to the NOF.
A lot has changed since the last clinician's guide was developed in the late 1990s and released in 1999, Dr. Lindsay said. "New drugs have been developed, and there have been new studies on the natural history of the disease."
The guide also covers the diverse U.S. population, he added. The foundation's earlier guide had focused on postmenopausal white women. "Since 1998, we have obtained information on men and non-Caucasian populations," Dr. Lindsay said, "so we can address the heterogeneity of the population in the United States."