Defining risk thresholds for a 10-year probability of hip fracture model that combines clinical risk factors and quantitative ultrasound: results using the EPISEM cohort

Quantitative Ultrasound (QUS) in the Management of Osteoporosis and Assessment of Fracture Risk

The use of quantitative ultrasound (QUS) for a variety of skeletal sites, associated with the absence of technology-specific guidelines, has created uncertainty with respect to the application of QUS results to the management of individual patients in clinical practice. However, when prospectively validated (this is not the case for all QUS devices and skeletal sites), QUS is a proven, low-cost, and readily accessible alternative to dual-energy X-ray absorptiometry (DXA) measurements of bone mineral density (BMD) for the assessment of fracture risk. Indeed, the clinical use of QUS to identify subjects at low or high risk of osteoporotic fracture should be considered when central DXA is unavailable. Furthermore, the use of QUS in conjunction with clinical risk factors (CRF),allows for the identification of subjects who have a low and high probability of osteoporotic fracture. Device- and parameter-specific thresholds should be developed and cross-validated to confirm the concurrent use of QUS and CRF for the institution of pharmacological therapy and monitoring therapy.

Performance of risk assessment instruments for predicting osteoporotic fracture risk: a systematic review

We systematically reviewed the literature on the performance of osteoporosis absolute fracture risk assessment instruments. Relatively few studies have evaluated the calibration of instruments in populations separate from their development cohorts, and findings are mixed. Many studies had methodological limitations making susceptibility to bias a concern.

INTRODUCTION

The aim of this study was to systematically review the literature on the performance of osteoporosis clinical fracture risk assessment instruments for predicting absolute fracture risk, or calibration, in populations other than their derivation cohorts.

METHODS

We performed a systematic review, and MEDLINE, Embase, Cochrane Library, and multiple other literature sources were searched. Inclusion and exclusion criteria were applied and data extracted, including information about study participants, study design, potential sources of bias, and predicted and observed fracture probabilities.

RESULTS

A total of 19,949 unique records were identified for review. Fourteen studies met inclusion criteria. There was substantial heterogeneity among included studies. Six studies assessed the WHO's Fracture Risk Assessment (FRAX) instrument in five separate cohorts, and a variety of risk assessment instruments were evaluated in the remainder of the studies. Approximately half found good instrument calibration, with observed fracture probabilities being close to predicted probabilities for different risk categories. Studies that assessed the calibration of FRAX found mixed performance in different populations. A similar proportion of studies that evaluated simple risk assessment instruments (≤5 variables) found good calibration when compared with studies that assessed complex instruments (>5 variables). Many studies had methodological features making them susceptible to bias.

CONCLUSIONS

Few studies have evaluated the performance or calibration of osteoporosis fracture risk assessment instruments in populations separate from their development cohorts. Findings are mixed, and many studies had methodological limitations making susceptibility to bias a possibility, raising concerns about use of these tools outside of the original derivation cohorts. Further studies are needed to assess the calibration of instruments in different populations prior to widespread use.

Cost effectiveness of secondary vs tertiary prevention for post-menopausal osteoporosis

BACKGROUND

The aging of the population is likely to increase the number of osteoporosis-related fractures, such as hip fractures, and hence the economic burden for society. Therefore, strategies to identify women at increased risk are of major interest.

OBJECTIVE

The aim of this study was to determine the cost effectiveness of preventive services for osteoporosis, comparing secondary plus tertiary prevention (SP/TP) versus tertiary prevention (TP) alone in post-menopausal women in Germany.

METHODS

A cost-utility analysis and a budget-impact analysis were performed from the perspective of the German statutory health insurance (SHI). A Markov model simulated costs and benefits discounted at 3% over a lifetime horizon.

RESULTS

Cost effectiveness of TP compared with no screening was 669 Euros, 477 Euros and 385 Euros per QALY for women aged 60, 70 and 80 years, respectively (year 2010 values). In women aged 50 years, TP dominated no prevention. Cost effectiveness of SP/TP compared with TP was 4543 Euros, 19791 Euros, 8670 Euros and 3368 Euros for women aged 50, 60, 70 and 80 years, respectively. SP/TP resulted in additional costs of 109 million Euros or 0.10% of the SHI's annual budget (TP alone = 8 million Euros).

CONCLUSION

Compared with TP, a strategy based on SP/TP appears to be more expensive but more effective in each age group. Given that cost effectiveness seems acceptable, allocation of resources to SP/TP to decrease post-menopausal osteoporotic fracture risk may be justified.

Phalangeal quantitative ultrasound and bone mineral density in evaluating cortical bone loss: a study in postmenopausal women with primary hyperparathyroidism and subclinical iatrogenic hyperthyroidism

Twenty-five postmenopausal women with primary hyperparathyroidism (PHPT) and 30 age-matched women with subclinical hyperthyroidism (sHTH) were studied to assess cortical bone loss. One hundred two healthy women were also recruited. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry at lumbar spine (LS), femoral neck (FN) and femoral total (FT), and at one-third of the radius (R). Amplitude-dependent speed of sound (ADSoS) and Ultrasound Bone Profile Index (UBPI) were also evaluated using phalangeal quantitative ultrasound (QUS). A significant correlation was found between QUS and BMD at LS (ADSoS, p < 0.05) and R (ADSoS and UBPI, p < 0.001) in controls. QUS significantly correlated with BMD at LS, FN (p < 0.01), and FT (p < 0.001) in sHTH. No correlations were found in the PHPT group. Mean T-score values of all parameters were significantly lower in patients compared with controls (p < 0.001); however, they did not differ between PHPT and sHTH patients. T-score of R, ADSoS, and UBPI was reduced compared with other sites (p < 0.001) in both diseases. In postmenopausal women with PHPT and sHTH, bone loss is mainly detectable at cortical level. However, qualitative and/or structural changes of bone could account for the lack of correlations between these 2 techniques at cortical sites.

Remaining lifetime and absolute 10-year probabilities of osteoporotic fracture in Swiss men and women

SUMMARY

Remaining lifetime and absolute 10-year probabilities for osteoporotic fractures were determined by gender, age, and BMD values. Remaining lifetime probability at age 50 years was 20.2% in men and 51.3% in women and increased with advancing age and decreasing BMD. The study validates the elements required to populate a Swiss-specific FRAX model.

INTRODUCTION

Switzerland belongs to high-risk countries for osteoporosis. Based on demographic projections, burden will still increase. We assessed remaining lifetime and absolute 10-year probabilities for osteoporotic fractures by gender, age and BMD in order to populate FRAX algorithm for Switzerland.

METHODS

Osteoporotic fracture incidence was determined from national epidemiological data for hospitalised fractured patients from the Swiss Federal Office of Statistics in 2000 and results of a prospective Swiss cohort with almost 5,000 fractured patients in 2006. Validated BMD-associated fracture risk was used together with national death incidence and risk tables to determine remaining lifetime and absolute 10-year fracture probabilities for hip and major osteoporotic (hip, spine, distal radius, proximal humerus) fractures.

RESULTS

Major osteoporotic fractures incidence was 773 and 2,078 per 100,000 men and women aged 50 and older. Corresponding remaining lifetime probabilities at age 50 were 20.2% and 51.3%. Hospitalisation for clinical spine, distal radius, and proximal humerus fractures reached 25%, 30% and 50%, respectively. Absolute 10-year probability of osteoporotic fracture increased with advancing age and decreasing BMD and was higher in women than in men.

CONCLUSION

This study validates the elements required to populate a Swiss-specific FRAX model, a country at highest risk for osteoporotic fractures.