Calcaneal Quantitative Ultrasound May Serve as a Prescreening Tool for Osteoporosis

Calcaneal quantitative ultrasound (QUS) has comparable diagnostic accuracy as dual-energy x-ray absorptiometry (DXA), the gold standard for diagnosing osteoporosis. Although it cannot replace DXA for diagnosing osteoporosis, it can be used as an effective prescreening tool prior to a DXA scan, researchers said it a recent study comparing the performance of the 2 screening methods.

Calcaneal quantitative ultrasound (QUS) has comparable diagnostic accuracy as dual-energy x-ray absorptiometry (DXA), the gold standard for diagnosing osteoporosis. Although it cannot replace DXA for diagnosing osteoporosis, it can be used as an effective prescreening tool prior to a DXA scan, researchers said it a recent study comparing the performance of the 2 screening methods.

As people are living longer, osteoporosis and osteoporotic fractures have become one of the biggest healthcare burdens throughout the world. It is estimated that the risk of an osteoporotic fracture is approximately 50% for women and 25% for men older than 50 years old. Diagnosing osteoporosis or preventing it through pharmacological therapies have become paramount, especially in the elderly population.

When diagnosing osteoporosis, the World Health Organization has defined it as a bone mineral density of —2.5 standard deviations (SDs) or greater below the average value for young healthy individuals as measured with DXA (T score of –2.5 of lower). Although this definition limits the diagnosis solely through DXA, prescreening tools can be done with other approaches such as QUS.

In a recent study, QUS was compared with DXA to evaluate the accuracy of QUS as a prescreening tool.

For 3 months, postmenopausal white women, 40 to 82 years old, were enrolled to have a DXA scan and a calcaneal QUS measurement. A total of 234 patients were included in the final analysis. When comparing patients with and without osteoporosis, investigators found that women with osteoporosis had lower T scores, body mass index, and QUS than patients without osteoporosis.

Correlations were then analyzed between QUS and DXA. A moderate, positive correlation was found for DXA and QUS measurements for the T score at the left hip and QUS T score at the left calcaneus (r = .515). However, there was less of a correlation when comparing T score and QUS T score at the lumbar spine (r = .397). Similarly, the QUS T score at the right calcaneus had a positive correlation with the T score of the DXA at the right hip (r = .505), with a slightly lower correlation at the lumbar spine (r = .404).

For QUS to be an acceptable alternative tool in place of DXA, suitable cutoffs had to be found to identify DXA T scores of —2.5 or lower, the defining score for osteoporosis.

Based on the population data, investigators found that —1.455 for the right QUS T score and –1.48 for the left QUS T score achieved adequate screening parameters to identify osteoporosis. Cutoff scores produced a sensitivity of 41% and a specificity of 86.6% for the right QUS T score and a sensitivity of 51.3% and a specificity of 83.3% for the left QUS T score.

QUS has become an area of interest because compared with DXA, QUS is radiation free, inexpensive, and time saving. Although QUS had poorer sensitivity, deeming it not a suitable device for diagnosing osteoporosis, it has shown to have respectable specificity, allowing its use as a prescreening tool. If positive results from a larger population representation are presented for QUS in the future, it may serve as a very convenient tool to screen out patients prior to the need for a DXA scan.

Reference

Steiner B, Dimai HP, Steiner H, Cirar S, Pammer A. Prescreening for osteoporosis with quantitative ultrasound in postmenopausal white women [published online October 20, 2018]. J Ultrasound Med. doi: 10.1002/jum.14844.