Bone mineral density and broadband ultrasound attenuation with estrogen treatment of postmenopausal women

Quantitative ultrasound in the management of osteoporosis: the 2007 ISCD Official Positions

Dual-energy X-ray absorptiometry (DXA) is commonly used in the care of patients for diagnostic classification of osteoporosis, low bone mass (osteopenia), or normal bone density; assessment of fracture risk; and monitoring changes in bone density over time. The development of other technologies for the evaluation of skeletal health has been associated with uncertainties regarding their applications in clinical practice. Quantitative ultrasound (QUS), a technology for measuring properties of bone at peripheral skeletal sites, is more portable and less expensive than DXA, without the use of ionizing radiation. The proliferation of QUS devices that are technologically diverse, measuring and reporting variable bone parameters in different ways, examining different skeletal sites, and having differing levels of validating data for association with DXA-measured bone density and fracture risk, has created many challenges in applying QUS for use in clinical practice. The International Society for Clinical Densitometry (ISCD) 2007 Position Development Conference (PDC) addressed clinical applications of QUS for fracture risk assessment, diagnosis of osteoporosis, treatment initiation, monitoring of treatment, and quality assurance/quality control. The ISCD Official Positions on QUS resulting from this PDC, the rationale for their establishment, and recommendations for further study are presented here.

The clinical use of quantitative ultrasound (QUS) in the detection and management of osteoporosis

For the detection and management of osteoporosis and osteoporosis-related fractures, quantitative ultrasound (QUS) is emerging as a relatively low-cost and readily accessible alternative to dual-energy X-ray absorptiometry (DXA) measurement of bone mineral density (BMD) in certain circumstances. The following is a brief, but thorough review of the existing literature with respect to the use of QUS in 6 settings: 1) assessing fragility fracture risk; 2) diagnosing osteoporosis; 3) initiating osteoporosis treatment; 4) monitoring osteoporosis treatment; 5) osteoporosis case finding; and 6) quality assurance and control. Many QUS devices exist that are quite different with respect to the parameters they measure and the strength of empirical evidence supporting their use. In general, heel QUS appears to be most tested and most effective. Overall, some, but not all, heel QUS devices are effective assessing fracture risk in some, but not all, populations, the evidence being strongest for Caucasian females over 55 years old. Otherwise, the evidence is fair with respect to certain devices allowing for the accurate diagnosis of likelihood of osteoporosis, and generally fair to poor in terms of QUS use when initiating or monitoring osteoporosis treatment. A reasonable protocol is proposed herein for case-finding purposes, which relies on a combined assessment of clinical risk factors (CR.F) and heel QUS. Finally, several recommendations are made for quality assurance and control.

Relationship between risk factors and QUS in a European Population: The OPUS study

There are many risk factors associated with low bone mineral density. Quantitative ultrasound (QUS) is a generally accepted method for measurement of bone and has been shown to be strongly associated with future fracture risk. The Osteoporosis and Ultrasound Study (OPUS) is a multi-centre European wide study examining 5 different QUS scanners (4 calcaneal, 1 finger device). The aim of this paper was to examine the relationship between risk factors (as assessed by questionnaire) and QUS measurements. 449 younger women (aged 20 to 39 years) and 2283 older women (aged 55 to 79 years) were included in this analysis. As expected, those with a self-reported previous fracture had lower QUS measurements than those without (P < 0.001). However, no significant difference was seen between those reporting a maternal hip fracture and those who did not report such an event. Differences were found for smokers vs. non-smokers for SOS but not for BUA measurements. Weight was positively correlated with all BUA variables but only with some SOS variables. We determined which risk factors were most strongly associated with QUS measurements by using step-wise multiple regression. Models for each QUS measurement were calculated, and the R2 values ranged from 0.18 to 0.28 for SOS, 0.27 to 0.32 for BUA and 0.31 to 0.42 for the finger QUS device. The most common risk factors across all models were age, use of hormone replacement therapy, self-reported previous fracture, self-reported diagnosis of osteoporosis, current weight, pulse rate and self-reported estimated height at age 20 years. We analysed relationships across the 5 centres and detected some geographical differences in the prevalence of the risk factors. In conclusion, similar relationships are seen with QUS measurements as are found for bone mineral density. However, the strength of the association is dependent on the type of QUS device and variable measured.

Monitoring alendronate and estradiol therapy with quantitative ultrasound and bone mineral density

Few studies have compared quantitative ultrasound with bone mineral density (BMD) in monitoring response to therapy in osteoporosis. The aim of our study was to compare finger ultrasound variables and BMD for monitoring alendronate and estradiol therapy in postmenopausal women. We recruited 26 women aged 50 to 79 yr (mean: 65 yr) with osteoporosis; 18 patients received 10 mg/d of alendronate and 500 mg/d of calcium carbonate and 8 patients received 500 mg/d of calcium carbonate only. We recruited 21 hysterectomized postmenopausal women who were randomized to treatment or control. The treatment group received a 25-mg estradiol implant, which was replaced every 6 mo. The control group had a sham procedure. In the alendronate group, there were significant changes at 1 yr at the lumbar spine (p<0.05), bone transmission time (p<0.01), and pure speed of sound (p<0.001) and the changes continued into the second year. In the estradiol implant group, there were significant changes at 1 yr at the lumbar spine (p<0.001), the femoral neck (p<0.05), and the pure speed of sound (p<0.01). For alendronate, the signal-to-noise ratio was similar between the lumbar spine and bone transmission time (1.8 and 1.4) and greater than for the pure speed of sound and femoral neck (0.8 and 0.7); for estradiol, the signal-to-noise ratio was similar between the lumbar spine and femoral neck (2.0 and 1.5) and greater than for the pure speed of sound and bone transmission time (1.1 and 0.6). These results indicated that changes in finger ultrasound are similar in clinical utility to dual-energy X-ray absorptiometry measurements at the femoral neck for the monitoring of antiresorptive treatments for osteoporosis.

The use of ultrasound in the assessment of bone status

The assessment of skeletal status has wide clinical applications, especially in the management of osteoporosis. Osteoporosis, once thought of as an unpreventable and untreatable aging process, has revealed many of its secrets over the last decade, and the advent of successful drug therapy has changed our perception of the disease. Non-invasive techniques play a fundamental role in the diagnosis of osteoporosis and in the assessment of the efficacy of drug treatments. The primary technique used in osteoporosis is dual X-ray absorptiometry (DXA), that has been established as a reliable means of measuring bone density. Quantitative ultrasound (QUS), because of the relative portability of the equipment, ease of use, lack of ionizing radiation and low cost, has great potential for widespread use. Five devices for QUS assessment have recently been approved by the Food and Drug Administration and many more applications are in progress. QUS is a relatively new technology, at least in its application to bone fragility. Nevertheless, QUS has demonstrated that it is able to detect bone fragility as well as DXA. However, diagnosis of osteoporosis by QUS remains contentious, but the problems are due more to the limitations of the present T-scores rather than to the technique. A better option for QUS would be to report results in terms of remaining lifetime fracture risk, keeping in mind that a risk estimate needs not only the QUS or DXA measurement, but also the specific data, such as age, weight, gender, hormonal status and fracture history of the patient.

Assessment by quantitative ultrasonometry of the effects of hormone replacement therapy on bone mass

OBJECTIVE

This study was undertaken to evaluate the impact of hormone replacement therapy on results of quantitative ultrasonometry of the heel.

STUDY DESIGN

A total of 2006 healthy perimenopausal women (mean age, 52.2 (10.3 years) were recruited in 5 German centers: 611 women (30%) had received hormone replacement therapy and 1395 (70%) had not. About 90% of the hormone replacement therapy users were current users, and the rest had stopped <6 months before the study. Speed of sound, broadband ultrasonographic attenuation, and the stiffness index were compared among the following groups: all users and nonusers of hormone replacement therapy, hormone replacement therapy users and nonuser control subjects matched for age and body mass index, and hormone replacement therapy users grouped in relation to the duration of hormone replacement therapy use and age and control subjects matched for body mass index.

RESULTS

Women who were using hormone replacement therapy had significantly higher values (P <.001) than did nonusers for all ultrasonographic variables, even after we controlled for age and body mass index. Women who had used hormone replacement therapy for >3 years had significantly higher values (P <.001) than did matched control subjects for all variables. Differences increased with the duration of hormone replacement therapy use.

CONCLUSION

Quantitative ultrasonometric measurement at the heel differentiates hormone replacement therapy users from nonusers, reflects duration of hormone replacement therapy use, and could be useful in both clinical trials and patient management.

Peripheral bone mass measurements: current and future perspectives on quantitative ultrasound and peripheral DXA

Although peripheral bone mass measurements have been available for more than a quarter of a century to predict osteoporotic fractures, these studies fell out of favor in the late 1980s and early 1990s as axial measurements replaced appendicular determinations for risk assessment and therapeutic responsiveness. Within the last half decade there has been a resurgence in utilization of peripheral measurements, primarily because of improved technology, enhanced precision, and greater accessibility. There are now nearly 11,000 peripheral densitometers in use around the world with quantitative ultrasound (QUS) of the calcaneus and peripheral densitometry (pDXA) of the wrist or calcaneus the most popular. Three recent prospective studies involving more than 20,000 postmenopausal women have demonstrated that QUS of the calcaneus can predict future fractures as accurately as central measurements of the spine or femur. This has raised the possibility that widespread screening with QUS or pDXA will soon become a reality. In this articles we hypothesize that global utilization of peripheral technology by primary care physicians is an absolutely necessity for the successful identification and treatment of all osteoporotic patients. But despite improvements in the accuracy and precision of these machines, several critical questions remain. In particular the issues which demand further study include: 1. The rate of false negative tests by peripheral instruments; 2. The utilization of appendicular sites to measure therapeutic efficacy of various antiosteoporotic drugs; 3. The timing of follow-up measurements to assess responsiveness; 4. The relationship between fracture risk education and incremental changes in bone mass; 5. The interrelationship between bone density and bone architecture and 6. cost effectiveness of peripheral vs central measurements. Notwithstanding these issues, peripheral scanning by one of several techniques is likely to be at the forefront of screening for osteoporosis risk, not only in specialized clinics but at the "point of care" in primary care offices.