Screening bone CT helps avoid osteoporosis fractures

By combining virtual bone-strength testing with standard bone mineral density testing—the former using quantitative CT, the latter with dual-energy x-ray absorptiometry (DXA)—clinicians can help postmenopausal women ward off a substantial number of painful fragility fractures.

In the process, they’d improve the women’s quality of life and help the healthcare system avoid costs that would have been incurred by treating such injuries.

The study behind the findings was conducted at New York University and published online June 14 in Radiology.

Christoph Agten, MD, and colleagues drew from the literature to develop a state-transition microsimulation model tracking a hypothetical cohort of 1 million postmenopausal women 55 or older living in the U.S. and at various levels of risk for osteoporosis.

The team compared three screening approaches against one another: no screening; screening with DXA alone (performed at rescreening intervals set by prior DXA results); and screening with DXA plus quantitative CT at different intervals (three, five and 10 years) and at different screening initiation ages (55 to 65 years).

For outcome measures, they used incremental cost-effectiveness ratios (ICERs) in 2015 U.S. dollars per quality-adjusted life year (QALY) gained and number of fragility fractures.

The researchers found the best and most cost-effective strategy was combined DXA and quantitative CT screening starting at age 55 with quantitative CT screening every five years (ICER, $2,000 per QALY).

This combination strategy yielded the lowest rate of hip fractures—12.8 percent versus 15.8 percent for DXA alone and 18.7 percent for no screening.

The combo group also had the fewest fractures of the vertebrae, wrist and other orthopedic areas.

The authors acknowledge several limitations in study design, including their simulation model’s reliance on data from American women with ready access to U.S. healthcare and their exclusion of the potential effects ionizing radiation might have on their model.

They point to quantitative hip CT’s comparatively low dose and note that that MRI could substitute in computing bone strength when radiation exposure is a major concern.

“[T]he combined assessment of bone strength and bone mineral density for osteoporosis in postmenopausal women has the potential to be a cost-effective screening strategy and to prevent a substantial number of fragility fractures,” Agten et al. conclude.