PRACTICE CHANGER
Reconsider the intervals at which you recommend rescreening for osteoporosis; for post-menopausal 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
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
ILLUSTRATIVE CASE
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 5 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 bone mineral density (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 8 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
STUDY SUMMARY: Longer intervals are reasonable for those at low risk
Gourlay et al followed 4957 women age ≥67 years 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 (95% confidence interval [CI], 11.5-24.6) for women with normal BMD
- 17.3 years (95% CI, 13.9-21.5) for women with mild osteopenia
- 4.7 years (95% CI, 4.2-5.2) for women with moderate osteopenia
- 1.1 year (95% CI, 1.0-1.3) for women with advanced osteopenia
Intervals until 2% of the cohort developed fractures were similar
Overall, the authors used a sensible approach to estimate reasonable intervals between DEXA screenings (TABLE)
TABLE
Suggested rescreening intervals based on DEXA scan results1
| DEXA result (T-score) | Rescreening interval* |
|---|---|
| Normal/mild osteopenia (> -1.50) | 15 years |
| Moderate osteopenia (-1.50 to -1.99) | 5 years |
| Advanced osteopenia (-2.0 to -2.49) | 1 year |
| *Consider reducing these intervals by one-third for women older than 80 years. | |
