The study in the New England Journal of Medicine (Gourlay et al, N Eng J Med 2012; 366: 225–33) found that less than 10% of postmenopausal women (aged 67 years or older) who had normal BMD or who had mild osteopenia would develop osteoporosis within a 15-year interval between a first and second DXA scan. It also found that less than 10% of women with moderate osteopenia would develop osteoporosis during a five-year interval and less than 10% of women with advanced osteopenia would develop the condition in one year. These results led to discussions about the appropriate length of time between DXA scans for patients at risk of osteoporosis.
In their viewpoint article, the inaugural article in Journal of Bone and Mineral Research’s new series of viewpoint features, E Michael Lewiecki, New Mexico Clinical Research & Osteoporosis Center, University of New Mexico School of Medicine, Albuquerque, USA, and co-authors argue that a 15-year interval between DXA scans is too long for many individuals. They claim that Margaret Gourlay, Department of Family Medicine, University of North Carolina, Chapel Hill, USA, and co-authors may have underestimated the number of patients who progressed to osteoporosis during their study because they did not measure lumbar spine BMD. Lewiecki et al, reported: “Low lumbar spine BMD is associated with increased risk of fracture at all skeletal sites. Moreover, lumbar spine T-score may be ≤-2.5 even if the femoral neck or total hip T-score is >-2.5.” However, they added that “most importantly”, Gourlay et al only focused on BMD and did not “capture those patients with osteopenia who by the FRAX fracture risk assessment would have been high risk for fracture and therefore warrant drug therapy.”
Lewiecki et al also stated that over-testing with DXA, as suggested by Gourlay et al’s study, is not the problem as the real problem is that “far too few patients are being screened for osteoporosis.” They said: “Although concerns have been raised that some screening prevention programmes for other chronic diseases do not result in healthcare savings, this is not the case for BMD testing in appropriately selected patients. The experience of healthcare systems suggests that increases in BMD testing reduce fracture rates and save money.”
John Bilezikian, Professor of Medicine and Pharmacology at College of Physicians and Surgeons, Columbia University and a co-author of the study, told Spinal News International: “The article by Gourlay et al. did not take into account factors that would lead to intervals earlier than 15 years in women over 67 who have normal or minimally low bone mineral density. Since we know that there are many factors, independent of bone mineral density that contribute to fracture risk, it is important for healthcare providers to be aware of them, as stated in our viewpoint article. It is thus apparent that the rather long interval of time between BMD testing, as recommended by Gourlay et al., covers a very small proportion of the “at risk” postmenopausal population. The article also failed to emphasise the point that many women older than 67 with moderate-to-severe osteopenia need much more frequent testing as do women in their earlier postmenopausal years.”