Bone Density: Repeat Testing May Not be Useful

Larry Hand

September 24, 2013

A second measure of bone mineral density (BMD) within 4 years of a first measure did not meaningfully improve prediction of hip or major osteoporotic fracture in a cohort of men and women, who were not being treated for osteoporosis, according to a study published in the September 25 issue of JAMA.

Sarah D. Berry, MD, MPH, from the Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts, and colleagues conducted a population-based cohort study of 310 men and 492 women from the Framingham Osteoporosis Study who had 2 measures of femoral neck BMD taken from 1987 through 1999. Participants had a mean age of 74.8 years.

A total of 1766 participants in the Framingham Osteoporosis Study were alive in January 1992, when second-round BMD testing began. The researchers excluded 931 (52.7%) participants who lacked a second test, and 33 (1.9%) who had hip fractures that occurred before the second test.

After a median follow-up of 9.6 years after the second BMD test, 113 people (14.1%) had 1 or more major osteoporotic fracture. They were more likely to be women, to report a prior fracture, and to have a lower body mass index and lower baseline BMD than participants who did not experience an osteoporotic event.

Using Cox proportional hazards models and the net reclassification index, the researchers found that the second BMD measurement increased the proportion of participants reclassified after the second test as high risk for hip fracture by 3.9% (95% confidence interval [CI], −2.2% to 9.9%) and decreased the proportion reclassified as low risk (−2.2%; 95% CI, −4.5% to 0.1%).

Medicare reimburses for BMD screening every 2 years, and the average time between tests is 2.2 years, the researchers write. According to Healthcare Blue Book, the price can be $111. Other sources put prices ranging from $150 to $250 without insurance to a copay with insurance.

"The second BMD measure resulted in a small proportion of individuals reclassified as high risk of hip or major osteoporotic fracture, and it is unclear whether this reclassification justifies the current US practice of performing serial BMD tests at 2.2-year intervals," the researchers write.

With Leeway

Despite this, the researchers write, "[W]e recognize that detecting BMD loss would have been paramount for the small numbers of individuals reclassified by a second BMD test who went on to experience a fracture. For these individuals a repeat screening test provides the opportunity for clinicians to intervene with osteoporosis medications that reduce the risk of fracture, even among persons 75 years or older."

"I don't want to sound too critical. The data are the data on one hand. On the other hand, what kind of effect does this [study] have? The effect is it makes it harder to practice medicine and it tends to shield you from making unique decisions in individual patients," Robert Recker, MD, director of the Osteoporosis Research Center at Creighton University School of Medicine, Omaha, Nebraska, and president of the National Osteoporosis Foundation, told Medscape Medical News.

"It handicaps physicians in trying to assess the individual and unique needs of patients. Most patients don't fit into any one construct," he continued. "One thing, for example, that this doesn't broach is people on treatment for osteoporosis. It looks like they eliminated higher-risk people from the study."

Patients receiving osteoporosis treatments sometimes do not gain mass and may actually lose mass, Dr. Recker continued. "There are a lot of situations where you need a bone mass measurement that is less than 2 years or 4 years. In other situations, you don't. As a practitioner, I need to have the ability to make those decisions without excessive cost and hassle. I point out that all you have to do is prevent one hip fracture and you've saved between $40,000 and $60,000."

This research was supported by the National Institutes of Health; the National Heart, Lung, and Blood Institute's Framingham Heart Study; and the Friends of Hebrew SeniorLife. Two authors report receiving royalties from UpToDate; 1 author reports receiving grants from Amgen, Eli Lilly, Hologic, Merck Sharp & Dohme, and Roche and consulting fees from Amgen, Ammonett Pharma, Eli Lilly, Merck Sharp & Dohme, and Novartis. Four authors report receiving funding from Novartis. The other authors and Dr. Recker have disclosed no relevant financial relationships.

JAMA. 2013;310:1256-1262. Abstract

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