Older women with normal bone mineral density may be able to defer retesting

New England Journal of Medicine Article: http://is.gd/juKpZa

Older women with bone mineral density (BMD) testing T scores greater than −1.50 have a low likelihood to develop osteoporosis and can defer retesting for 15 years, researchers concluded.

Researchers studied 4,957 women, 67 years of age or older, with normal BMD (T score at the femoral neck and total hip, −1.00 or higher) or osteopenia (T score, −1.01 to −2.49) and with no history of hip or clinical vertebral fracture or of treatment for osteoporosis, followed prospectively for up to 15 years.

Researchers then measured the estimated time for 10% of women to develop osteoporosis, with adjustment for estrogen use and other clinical risk factors. Incident hip and clinical vertebral fractures and treatment with bisphosphonates, calcitonin or raloxifene were treated as competing risks. Results appeared in the Jan. 19 New England Journal of Medicine.

Estimated time to osteoporosis was 16.8 years (95% CI, 11.5 to 24.6 years) for women with normal BMD, 17.3 years (95% CI, 13.9 to 21.5 years) for women with mild osteopenia, 4.7 years (95% CI, 4.2 to 5.2 years) for women with moderate osteopenia, and 1.1 years (95% CI, 1.0 to 1.3 years) for women with advanced osteopenia.

For women with osteopenia at baseline, significant predictors of osteoporosis were T-score group, age, body mass index (BMI), current estrogen use, and the interaction of T-score group by BMI (P<0.02). Non-significant predictors included any fracture after 50 years of age, current smoking, previous or current use of oral glucocorticoids, and self-reported rheumatoid arthritis (all P>0.20). Baseline T score is the most important factor, the authors concluded.

The authors wrote, "During the 15-year study period, less than 1% of women with T scores indicating normal BMD and 5% of women with T scores indicating mild osteopenia at their first assessment made the transition to osteoporosis, with an estimated testing interval of about 15 years for 10% of women in each of these groups to make the transition. This finding suggests that if BMD testing is deferred for 15 years among women with T scores greater than −1.50, there is a low likelihood of a transition to osteoporosis during that period."

Clinicians can reevaluate patients sooner if there is evidence of decreased activity or mobility, weight loss or other risk factors not considered in the analyses. The estimated time to osteoporosis decreased with increasing age, so that a screening interval of three years instead of five years might be considered for women 85 years of age or older who have moderate osteopenia, the authors said.