But expert says dual-energy X-rays still gold standard for measuring bone strength
TUESDAY, June 24 (HealthDay News) -- By combining the results of a heel ultrasound with known risk factors for osteoporotic fractures, Swiss researchers were better able to assess which women faced a greater risk of hip fracture.
According to the study of more than 6,000 women, which was published in the July issue of Radiology, 6.1 percent of women in the group identified as high risk went on to have a hip fracture, while just 1.8 percent of the women in the low-risk group did.
"The results [of our study] show that this predictive rule is not only effective at identifying high-risk patients who should receive further testing, but also may be helpful in identifying patients for whom further testing can be avoided," said study author Dr. Idris Guessous, a senior research fellow at Lausanne University Hospital in Switzerland.
"Osteoporosis is a major public health issue expected to increase in association with the worldwide aging of the population," he explained. "The incidence of osteoporosis will outpace economic resources, and the development of strategies to better identify women who need and women who do not need to be treated is crucial. One potential approach is the use of the prediction rule combining heel quantitative ultrasound and clinical risk factors."
However, at least one expert thinks ultrasound technology has a way to go before it can compare to the current gold standard of bone density testing -- dual-energy X-ray absorptiometry (DEXA).
"This study could be useful; it could give options to populations that don't have access to the gold standard test, but at this point, there's nothing that's as good as the gold standard, DEXA," said Dr. Judi Chervenak, a menopause and bone health expert at Montefiore Medical Center in New York City.
The current study included 9,174 Swiss women between the ages of 70 and 85. The women were interviewed and asked about known osteoporosis risk factors, as well as socioeconomic factors. All of the women also underwent heel quantitative ultrasound testing. The average follow-up time was three years.
The researchers found that combining four clinical risk factors -- older age, history of fracture, a failed chair test or a recent fall, with a low heel ultrasound score was better at predicting the risk of a future fracture than ultrasound alone. A failed chair test meant that a woman couldn't rise from a chair three successive times without using the arms of the chair.
By using the two methods together -- what the researchers called the predictive rule -- they were able to better identify which women were at-risk for a fracture.
Of those women who had a fracture, 90 percent were identified as high risk using the predictive rule.
Chervenak said there are drawbacks to this method, however. She explained that there are two types of bone that need to be assessed: cortical, which is found in the hip, and trabecular, which is found in the spine. Ultrasound is good for assessing cortical bone, but will likely miss problems in trabecular bone.
Additionally, she said that there is no standardized ultrasound test yet, and different centers use different machines.
The bottom line, Chervenak said, is that she doesn't think bone density testing will change significantly any time soon. This is a "well-designed study, and they're trying to create an easy-to-use algorithm, but assessing risk is a skill, and each woman has to be assessed individually," she concluded.
To learn more about bone density testing, visit the National Osteoporosis Foundation.
SOURCES: Idris Guessous, M.D., senior research fellow, Lausanne University Hospital, Switzerland; Judi Chervenak, M.D., menopause and bone health expert, department of obstetrics and gynecology, Montefiore Medical Center, New York City; July 2008, Radiology
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