A 65-year-old woman undergoes routine screening dual-energy x-ray absorptiometry (DXA), which reveals T scores of −2.3 at the femoral neck, −2.7 at the Ward triangle, −2.2 at the total hip, and −1.9 at the posteroanterior (PA) lumbar spine. Evaluation reveals no secondary cause of osteoporosis. She asks whether you recommend medication for osteoporosis.
Osteoporotic fractures—hip fractures in particular—are associated with tremendous medical and economic effects. Bone mineral density (BMD) is the best predictor of fracture in the absence of prior fracture, and thus DXA is a crucial tool for identifying patients at high risk. Unfortunately, the quality of DXA reporting is variable, and misleading information may result in inappropriate care. In this issue of JAMA Internal Medicine, Fenton and colleagues1 describe initiation of osteoporosis treatment in women aged 40 to 85 years in their regional health care system. They identified women with densitometric osteoporosis, defined as a T score of −2.5 or less at the total PA lumbar spine or femoral neck. These sites, as well as the total hip, are approved by the International Society for Clinical Densitometry (ISCD)2 for use in osteoporosis diagnosis in postmenopausal women and men 50 years or older. Fenton et al also identified women with low bone mass (osteopenia) at those main sites and women with osteoporosis-range BMD at non–main sites, such as the Ward triangle and lateral lumbar spine. The investigators present their findings as a barometer for how we are targeting patients for pharmacotherapy.
Kim TY, Schafer AL. Variability in DXA Reporting and Other Challenges in Osteoporosis Evaluation. JAMA Intern Med. 2016;176(3):393-395. doi:10.1001/jamainternmed.2015.7550