Ultrasound vs. DXA

[Guest guest]

Hi folks:

This paper suggests that calcaneal ultrasound measurement of bone

mass is somewhat superior to DXA for the prospective prediction of

bone fracture. And it is quick (two minutes), involves no

radiation, and is very inexpensive (simple equipment and quick) and

involves much less opportunity for operator error.

Why does anyone use DXA? Could it be that a quick examination

doesn't provide as much revenue per visit? If there is another

reason perhaps anyone who knows what it is could enlighten us?

My opinion is that those who keep saying DXA is the 'gold standard'

have spent too much time reading the promotional literature, and too

little time exercising their grey cells in the matter of DXA's

shortcomings.

This happens to be very relevant to me because I am having frequent

calcaneal ultrasound tests as part of my bone mass experiment. I

certainly would not want to have frequent exposure to DXA radiation.

Here is the paper:

J Bone Miner Res. 2006 Mar;21(3):413-8. Epub 2005 Dec 19.

" Long-term fracture prediction by DXA and QUS: a 10-year prospective

study. "

A, Kumar V, Reid DM.

Osteoporosis Research Unit, Department of Medicine and Therapeutics,

University of Aberdeen, Aberdeen, United Kingdom.

a.stewart@...

" This study investigated the ability of DXA and QUS to predict

fractures long term when measured around the time of the menopause.

We found both DXA and QUS are able to predict both any fracture

and " osteoporotic " fractures and that QUS can predict independently

of BMD. INTRODUCTION: There are now many treatments available for

prevention of osteoporotic fracture. To be cost-effective, we need

to target those most at risk. This study examines the ability of DXA

and QUS to predict fractures in an early postmenopausal population

of women. MATERIALS AND METHODS: We prospectively measured 3883

women who had been randomly selected from a community-based

register. At baseline, they were measured using DXA of spine and hip

(Norland XR-26) and QUS of the heel ( Sonix UBA 575). Follow-

up had a mean of 9.7 +/- 1.1 (SD) years. All incident fractures were

identified and validated by examination of X-ray reports, and these

were compared with those without fracture in a -regression model

to calculate hazard ratios (HRs). RESULTS: We found adjusted HRs for

any fracture per 1 SD reduction in spine BMD to be 1.61 (1.42-1.83),

whereas neck of femur BMD was 1.54 (1.34-1.75). Areas under the

curve (AUC) for a receiver operator characteristic (ROC) analysis

were 0.62 for spine BMD and 0.59 for neck BMD. In a subgroup where

QUS was also measured, the HR for a 1 SD reduction in BMD was 1.69

(1.29-2.22) for spine BMD and 1.55 (1.17-2.06) for neck BMD. The HR

for a 1 SD reduction in broadband ultrasound attenuation (BUA) was

1.53 (1.19-1.96), and 1.44 (1.12-1.86) when further adjusted for

neck BMD. The AUCs were 0.63 for spine BMD, 0.59 for neck BMD, and

0.62 for BUA. When only osteoporotic fractures were examined, the

HRs increased in all situations. BUA showed the highest HR of 2.25

(1.51-3.34), and when further adjusted for neck BMD was 2.12 (1.38-

3.28). CONCLUSIONS: In conclusion, it may be possible to scan women

around the time of the menopause to predict future fractures. It

seems that, for " osteoporotic " fractures, BUA may be an improved

predictor of fractures in comparison with DXA, because the relative

risk is highest for BUA, and independent of BMD. "

PMID: 16491289

Rodney.