Reconsider the intervals at which you recommend rescreening for osteoporosis; for postmenopausal women with a baseline of normal bone mineral density (BMD) or mild osteopenia, a 15-year interval is probably sufficient.1
Strength of recommendation
B: Based on a single cohort study.
A 67-year-old woman whose recent dual-energy x-ray absorptiometry (DEXA) scan showed mild osteopenia asks when she should have her next bone scan. What should you tell her?
One in five people who sustain a hip fracture die within a year,2 and as many as 36% die prematurely.3 Osteoporosis is the primary predictor of fracture risk and, in older white women in particular, low BMD increases the likelihood of fracture by 70% to 80%.4
Optimal Screening Frequency Not Known
The US Preventive Services Task Force (USPSTF) guideline for osteoporosis screening concludes that there is a lack of evidence about optimal rescreening intervals and states that intervals > 2 years may be necessary to better predict fracture risk.5 In addition, the USPSTF cites a prospective study showing that repeat measurement of BMD after eight years added little predictive value, compared with baseline DEXA scan results.6
The prospective cohort study detailed below was undertaken to help guide decisions about how frequently to screen.
Longer intervals are reasonable for those at low risk
Gourlay et al followed 4,957 women ages 67 or older with normal BMD or osteopenia and no history of hip or clinical vertebral fracture or osteoporosis treatment. The primary outcome was the estimated time it would take for 10% of the women to develop osteoporosis. The time until 2% of the women developed such a fracture was the secondary outcome.
Participants had baseline DEXA scans, which were repeated at years 2, 6, 8, 10, and 16. The researchers followed the women until they were diagnosed with osteoporosis, started on medication for osteoporosis, or developed a hip or clinical vertebral fracture.
After adjusting for multiple covariates (age, body mass index, smoking status, use of glucocorticoids, fracture after age 50, estrogen use, and rheumatoid arthritis), the intervals between baseline testing and the development of osteoporosis were:
• 16.8 years for women with normal BMD
• 17.3 years for women with mild osteopenia
• 4.7 years for women with moderate osteopenia
• 1.1 year for women with advanced osteopenia.
Intervals until 2% of the cohort developed fractures were similar.
Overall, a sensible approach was used to estimate reasonable intervals between DEXA screenings: 15 years for women with normal/mild osteopenia (T-score, > –1.50), five years for those with moderate osteopenia (–1.50 to –1.99), and one year for those with advanced osteopenia (–2.00 to –2.49).
Many DEXA scans can be eliminated
Rescreening all postmenopausal women every two years is unlikely to reduce osteoporotic fractures. This cohort study provides evidence that rescreening can often be delayed for many years, depending on the patient’s baseline risk. Changing practice based on these findings can reduce resource utilization without adversely affecting women’s health.
Questions about applicability may remain
This analysis was limited to women ≥ 67, so different results might be obtained from analyses that included younger postmenopausal women. In addition, 99% of the participants were white. Because the prevalence of osteoporosis of the hip among white women is equal to or slightly higher than it is among nonwhite women, it is likely that the suggested intervals are reasonable estimates for women of all races.
In women older than 80, the interval between baseline testing and the development of osteoporosis was shorter than that of their younger counterparts. Thus, it might be reasonable to reduce rescreening intervals by one-third for women in their 80s.
Challenges to Implementation
Education needed for patients and clinicians
This study is the best so far to address the frequency of rescreening. In order to implement it, patients as well as clinicians will need to be educated. Effective long-term (> 10 y) reminder systems would improve implementation.
The recommendations of professional associations may also be a factor. The National Osteoporosis Foundation recommends assessing BMD every two years, but notes that more frequent testing may sometimes be warranted.7 The American College of Preventive Medicine recommends that screening for osteoporosis not occur more often than every two years.8
1. Gourlay ML, Fine JP, Preisser JS, et al. Bone-density testing interval and transition to osteoporosis in older women. N Engl J Med. 2012;366:225-233.
2. Leibson CL, Tosteson AN, Gabriel SE, et al. Mortality, disability, and nursing home use for persons with and without hip fracture. J Am Geriatr Soc. 2002;50:1644-1650.
3. Abrahamsen B, van Staa T, Ariely R, et al. Excess mortality following hip fracture: a systematic epidemiological review. Osteoporosis Int. 2009;20: 1633-1650.
4. Smith J, Shoukri K. Diagnosis of osteoporosis. Clin Cornerstone. 2000;2:22-33.
5. US Preventive Services Task Force. Screening for osteoporosis: US Preventive Services Task Force recommendation statement. www.uspreventiveservicestaskforce.org/uspstf10/osteoporosis/osteors.htm. Accessed June 15, 2012.
6. Hillier TA, Stone KL, Bauer DC, et al. Evaluating the value of repeat bone mineral density measurement and prediction of fractures in older women. Arch Intern Med. 2007;167:155-160.
7. National Osteoporosis Foundation. Clinician’s guide to prevention and treatment of osteoporosis. 2010. www.nof.org/sites/default/files/pdfs/NOF_ClinicianGuide2009_v7.pdf. Accessed June 30, 2012.
8. Lim LS, Hoeksema LJ, Sherin K; ACPM Prevention Practice Committee. Screening for osteoporosis in the adult US population: ACPM position statement on preventive practice. Am J Prev Med. 2009;36:366-375.
The PURLs Surveillance System is supported in part by Grant Number UL1RR024999 from the National Center for Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center for Research Resources or the National Institutes of Health.
Copyright © 2012 The Family Physicians Inquiries Network. All rights reserved. Reprinted with permission from the Family Physicians Inquiries Network and The Journal of Family Practice. 2012;61(9):555-556.