B one mineral density (BMD) testing is recommended in older adults to determine their risk of hip or other major osteoporotic fractures common with age. Medicaid reimburses for screening every two years, but whether repeated testing is actually beneficial isn't known. Participants in a recent analysis were drawn from the cohort enrolled, beginning in 1948, in the Framingham Osteoporosis Study; they were invited to receive two BMD tests between 1987 and 1999. A total of 310 men and 492 women received two BMD tests and were included in the study; tests were conducted a mean of nearly four years apart. The participants' mean age at baseline was 74.
At a mean of 10 years of follow-up, the risk of hip fracture was slightly lower (10%) in participants whose annual percentage change in BMD equaled the expected age- and sex-matched mean for the general population than in those with a percentage change 1 SD below the mean (14%). Similarly, the risk of other osteoporotic fractures (spine, forearm, or shoulder) was 16% in those at the mean BMD percentage change and 18% in those 1 SD below the mean.
After the second BMD test, 48 participants were reclassified as being at high risk for hip fracture. Of those, four (8%) experienced a fracture, compared with one (3%) of the 29 participants who were reclassified as being at low risk. In terms of other osteoporotic fractures, retesting was slightly more helpful: 55 participants were reclassified as being at high risk and 12 as being at low risk after the second BMD test; of those, 12 (22%) and one (8%) experienced a fracture, respectively.
The authors conclude that repeating the BMD test did not provide significant information concerning fracture risk that couldn't already be discerned from the initial measurement and clinical characteristics (assessed over time) such as smoking, glucocorticoid use, alcohol use, and changes in body mass index. They do recommend that their research be replicated in nonwhite populations in whom the significance of repeated BMD testing might be greater.
Berry SD, et al. JAMA 2013;310(12):1256-62.