Screening for osteoporosis with bone mineral density (BMD) is recommended for older adults; however, it is unclear whether repeating a BMD screening test improves fracture risk assessment. The aim of the study presented below was to determine whether changes in BMD after 4 years provide additional information on fracture risk beyond baseline BMD and to quantify the change in fracture risk classification by the FRAX model after a second BMD measure . The cohort included 310 men and 492 women from the Framingham Osteoporosis Study with two measures of femoral neck BMD taken from 1987 through 1999. Participants were followed through 2009 or 12 years following the second BMD measure. Patients with a history of hip fracture were excluded. The mean age was 74.8 years. Less than one-quarter had normal basal BMD ([i]T[/i]-score up to 1), a little more than one-half had osteopenia ([i]T[/i]-score between 1 and 2.5), and almost one-quarter were osteoporotic. The mean (standard deviation, SD) BMD change was −0.6% per year (1.8%). Throughout a median follow-up of 9.6 years, 76 participants experienced an incident hip fracture and 113 participants experienced a major osteoporotic fracture. Annual percent BMD change per SD decrease was associated with risk of hip fracture (hazard ratio (HR) 1.43; 95% CI 1.16–1.78) and major osteoporotic fracture (HR 1.21; 95% CI 1.01–1.45) after adjusting for baseline BMD. At 10 years’ follow-up, 1 SD decrease in annual percent BMD change compared with the mean BMD change was associated with 3.9 excess hip fractures per 100 persons. Using the net reclassification index, a second BMD measure increased the proportion of participants reclassified as at high risk of hip fracture by 3.9% (95% CI −2.2% to 9.9%), whereas it decreased the proportion classified as at low risk by −2.2% (95% CI −4.5% to 0.1%). The conclusion was that, in untreated men and women of mean age 75 years, a second BMD measure after 4 years did not meaningfully improve the prediction of hip or major osteoporotic fracture. Repeating a BMD measure within 4 years to improve fracture risk stratification may not be necessary in adults of this age untreated for osteoporosis.
Department of Medicine T, Ichilov Hospital, Tel-Aviv, Israel
Berry SD, Samelson EJ, Pencina MJ, et al. Repeat bone mineral density screening and prediction of hip and major osteoporotic fracture. JAMA 2013;310:1256-62.
US Preventive Services Task Force. Screening for osteoporosis. Ann Intern Med 2011;154:356-64.
Lewiecki EM. Bone density measurement and assessment of fracture risk. Clin Obstet Gynecol 2013 Sep 6. Epub ahead of print.