The Performance of a Calcaneal Quantitative Ultrasound Device, CM-200, in Stratifying Osteoporosis Risk among Malaysian Population Aged 40 Years and Above

BACKGROUND

Calcaneal quantitative ultrasound (QUS) is widely used in osteoporosis screening, but the cut-off values for risk stratification remain unclear. This study validates the performance of a calcaneal QUS device (CM-200) using dual-energy X-ray absorptiometry (DXA) as the reference and establishes a new set of cut-off values for CM-200 in identifying subjects with osteoporosis.

METHODS

The bone health status of Malaysians aged ≥40 years was assessed using CM-200 and DXA. Sensitivity, specificity, area under the curve (AUC) and the optimal cut-off values for risk stratification of CM-200 were determined using receiver operating characteristic (ROC) curves and Youden's index (J). Results: From the data of 786 subjects, CM-200 (QUS T-score <-1) showed a sensitivity of 82.1% (95% CI: 77.9-85.7%), specificity of 51.5% (95% CI: 46.5-56.6%) and AUC of 0.668 (95% CI: 0.630-0.706) in identifying subjects with suboptimal bone health (DXA T-score <-1) (p < 0.001). At QUS T-score ≤-2.5, CM-200 was ineffective in identifying subjects with osteoporosis (DXA T-score ≤-2.5) (sensitivity 14.4% (95% CI: 8.1-23.0%); specificity 96.1% (95% CI: 94.4-97.4%); AUC 0.553 (95% CI: 0.488-0.617); p > 0.05). Modified cut-off values for the QUS T-score improved the performance of CM-200 in identifying subjects with osteopenia (sensitivity 67.7% (95% CI: 62.8-72.3%); specificity 72.8% (95% CI: 68.1-77.2%); J = 0.405; AUC 0.702 (95% CI: 0.666-0.739); p < 0.001) and osteoporosis (sensitivity 79.4% (95% CI: 70.0-86.9%); specificity 61.8% (95% CI: 58.1-65.5%); J = 0.412; AUC 0.706 (95% CI: 0.654-0.758); p < 0.001). Conclusion: The modified cut-off values significantly improved the performance of CM-200 in identifying individuals with osteoporosis. Since these values are device-specific, optimization is necessary for accurate detection of individuals at risk for osteoporosis using QUS.

Cost-effectiveness of osteoporosis screening strategies for hip fracture prevention in older Chinese people: a decision tree modeling study in the Mr. OS and Ms. OS cohort in Hong Kong

Despite the high costs of hip fracture, many governments provide limited support for osteoporosis screening. We demonstrated that osteoporosis screening by dual-energy X-ray absorptiometry (DXA) with or without pre-screening by Fracture Risk Assessment Tool (FRAX) or calcaneal ultrasound are more cost-effective than no screening in Chinese people aged 65 or over in Hong Kong.

INTRODUCTION

To examine the cost-effective potential osteoporosis screening strategies for hip fracture prevention in Hong Kong.

METHODS

Decision tree models were constructed to evaluate the cost per quality-adjusted life years (QALYs) of the different osteoporosis screening strategies followed by subsequent 5-year treatment with alendronate compared to no screening (but treat if a hip fracture occurs). The multiple osteoporosis screening strategies were composed of alternative tests and initiation age groups were evaluated with a 10-year horizon, and treatment were assigned if central dual-energy X-ray absorptiometry (DXA) T-score (at either the hip or spine) is - 2.5 or less. Strategies included DXA for all people and pre-screening with the Fracture Risk Assessment Tool (FRAX) at specific thresholds or by calcaneal quantitative ultrasonography (QUS) before taking DXA examination. All the model inputs were based on the Mr. OS and Ms. OS Hong Kong cohort; data are obtained from the Social Welfare Department or the published literature.

RESULTS

All of the screening strategies, including the universal screening with DXA and the pre-screening with FRAX or QUS before DXA, were consistently more cost-effective than no screening for people aged 65 years old or over. One-way sensitivity analysis with a more optimistic assumption on treatment adherence or inclusion of other major osteoporotic fractures did not change the results materially. Probabilistic sensitivity analyses showed a dominant role of pre-screening with FRAX followed by subsequent osteoporosis drug treatment in people aged 70 years old or over in Hong Kong.

CONCLUSIONS

Osteoporosis screening strategies based on DXA with or without pre-screening are more cost-effective compared to no screening for Chinese people aged 65 or over in Hong Kong.

Osteoporosis in East Asia: Current issues in assessment and management

The greatest burden of hip fractures around the world is expected to occur in East Asia, especially China. However, there is a relative paucity of information on the epidemiology and burden of fractures in East Asia. Osteoporosis is greatly under-diagnosed and under-treated, even among the highest-risk subjects who have already suffered fractures. The accessibility to bone densitometry, the awareness of the disease by professionals and the public, and the use and reimbursement of drugs are some of the areas which need improvement especially. Cost-effective analysis on screening strategy and intervention thresholds based on local epidemiology data and economic status are available only in Japan. In addition, clinical risk factor models for the assessment of fracture probability may be ethnic specific. Further research is needed to develop a cost-effective risk assessment strategy to identify high-risk individuals for screening and treatment based on local data. Moreover, inadequate calcium and vitamin D intake is still an issue faced by this region.

Techniques for diagnosing osteoporosis: a systematic review of cost-effectiveness studies

OBJECTIVES

The study question was whether dual-energy X-ray absorptiometry (DXA) alone is more cost-effective for identifying postmenopausal women with osteoporosis than a two-step procedure with quantitative ultrasound sonography (QUS) plus DXA. To answer this question, a systematic review was performed.

METHODS

Electronic databases (PubMed, INAHTA, Health Evidence Network, NIHR, the Health Technology Assessment program, the NHS Economic Evaluation Database, Research Papers in Economics, Web of Science, Scopus, and EconLit) were searched for cost-effectiveness publications. Two independent reviewers selected eligible publications based on the inclusion/exclusion criteria. Quality assessment of economic evaluations was undertaken using the Drummond checklist.

RESULTS

Seven journal articles and four reports were reviewed. The cost per true positive case diagnosed by DXA was found to be higher than that for diagnosis by QUS+DXA in two articles. In one article it was found to be lower. In three studies, the results were not conclusive. These articles were characterized by the differences in the types of devices, parameters and thresholds on the QUS and DXA tests and the unit costs of the DXA and QUS tests as well as by variability in the sensitivity and specificity of the techniques and the prevalence of osteoporosis.

CONCLUSIONS

The publications reviewed did not provide clear-cut evidence for drawing conclusions about which screening test may be more cost-effective for identifying postmenopausal women with osteoporosis.

A systematic review of models used in cost-effectiveness analyses of preventing osteoporotic fractures

This review was aimed at the evolution of health economic models used in evaluations of clinical approaches aimed at preventing osteoporotic fractures. Models have improved, with medical continuance becoming increasingly recognized as a contributor to health and economic outcomes, as well as advancements in epidemiological data. Model-based health economic evaluation studies are increasingly used to investigate the cost-effectiveness of osteoporotic fracture preventions and treatments. The objective of this study was to carry out a systematic review of the evolution of health economic models used in the evaluation of osteoporotic fracture preventions. Electronic searches within MEDLINE and EMBASE were carried out using a predefined search strategy. Inclusion and exclusion criteria were used to select relevant studies. References listed of included studies were searched to identify any potential study that was not captured in our electronic search. Data on country, interventions, type of fracture prevention, evaluation perspective, type of model, time horizon, fracture sites, expressed costs, types of costs included, and effectiveness measurement were extracted. Seventy-four models were described in 104 publications, of which 69% were European. Earlier models focused mainly on hip, vertebral, and wrist fracture, but later models included multiple fracture sites (humerus, pelvis, tibia, and other fractures). Modeling techniques have evolved from simple decision trees, through deterministic Markov processes to individual patient simulation models accounting for uncertainty in multiple parameters. Treatment continuance has been increasingly taken into account in the models in the last decade. Models have evolved in their complexity and emphasis, with medical continuance becoming increasingly recognized as a contributor to health and economic outcomes. This evolution may be driven in part by the desire to capture all the important differentiating characteristics of medications under scrutiny, as well as the advancement in epidemiological data relevant to osteoporosis fractures.

Cost effectiveness of denosumab compared with oral bisphosphonates in the treatment of post-menopausal osteoporotic women in Belgium

BACKGROUND

Denosumab has recently been shown to be well tolerated, to increase bone mineral density (BMD) and to significantly reduce the risk of hip, vertebral and non-vertebral fractures in the FREEDOM (Fracture REduction Evaluation of Denosumab in Osteoporosis every 6 Months) trial. It is becoming increasingly important to evaluate not only the therapeutic value of a new drug but also the cost effectiveness compared with the most relevant treatment alternatives.

OBJECTIVE

The objective of this study was to estimate the cost effectiveness of denosumab compared with oral bisphosphonates (branded and generic drugs) in the treatment of post-menopausal osteoporotic women in Belgium.

METHODS

Cost effectiveness of 3 years of treatment with denosumab was compared with branded risedronate and branded and generic alendronate using an updated version of a previously validated Markov microsimulation model. The model was populated with relevant cost, adherence and epidemiological data for Belgium from a payer perspective and the results were presented as costs per QALY gained (&U20AC;, year 2009 values). Analyses were performed in populations (aged ≥60 years) in which osteoporosis medications are currently reimbursed in many European countries, i.e. those with BMD T-score of -2.5 or less or prevalent vertebral fracture. Patients receiving denosumab were assumed to have a 46% lower risk of discontinuation than those receiving oral bisphosphonates, and the effect of denosumab after treatment cessation was assumed to decline linearly to zero over a maximum of 1 year.

RESULTS

Denosumab was cost effective compared with all other therapies, assuming a willingness to pay of &U20AC;40 000 per QALY gained. In particular, denosumab was found to be cost effective compared with branded alendronate and risedronate at a threshold value of &U20AC;30 000 per QALY and denosumab was dominant (i.e. lower cost and greater effectiveness) compared with risedronate from the age of 70 years in women with a T-score of -2.5 or less and no prior fractures. The cost effectiveness of denosumab compared with generic alendronate was estimated at &U20AC;38 514, &U20AC;22 220 and &U20AC;27 862 per QALY for women aged 60, 70 and 80 years, respectively, with T-scores of -2.5 or less. The equivalent values were &U20AC;37 167, &U20AC;19 718 and &U20AC;19 638 per QALY for women with prevalent vertebral fractures.

CONCLUSION

This study suggests, on the basis of currently available data, that denosumab is a cost-effective strategy compared with oral bisphosphonates (including generic alendronate) for the treatment of post-menopausal osteoporotic women, aged ≥60 years in Belgium. Denosumab therefore appears to have the potential to become a first-line treatment for post-menopausal women with osteoporosis. However, further studies would be required to evaluate the long-term safety and adherence of denosumab in real-world clinical practice as well as head-to-head effectiveness compared with oral bisphosphonates.

Potential cost-effectiveness of denosumab for the treatment of postmenopausal osteoporotic women

Denosumab has recently been shown to be safe and to significantly reduce the risk of vertebral, hip and non-vertebral fractures in the "Fracture REduction Evaluation of Denosumab in Osteoporosis every 6Months" (FREEDOM) Trial. Besides the clinical profile of a new drug, it becomes increasingly important to assess whether the drug represents good value for money. This study aims to examine the potential cost-effectiveness of denosumab in the treatment of postmenopausal osteoporotic women. An updated version of a validated Markov microsimulation model was used to estimate the cost (euro2009) per quality-adjusted life-year (QALY) gained of a 3-year denosumab treatment compared with no treatment. The model was populated with cost and epidemiological data for Belgium from a health-care perspective and the base-case population was defined from the FREEDOM Trial. The effect of denosumab after treatment cessation was conservatively assumed to decline linearly over 1year. Uncertainty was investigated using one-way and probabilistic sensitivity analyses. In particular, additional analyses were performed in populations (over 60 years) where osteoporosis medications are currently reimbursed in many European countries, i.e. with bone mineral density (BMD) T-score < or = -2.5 or prevalent vertebral fracture. In the base-case analysis, the cost per QALY gained of denosumab compared with no treatment was estimated at euro28,441. This value decreased to euro15,532 and to euro11,603 for women with a BMD T-score of -2.5 or prevalent vertebral fracture, respectively. Additional analyses showed that the cost-effectiveness of denosumab fall below commonly accepted threshold of euro 30,000per QALY gained for women with a BMD T-score < or = -2.5 or prevalent vertebral fracture, over the entire age range examined (60-80 years). The results were robust under a wide range of plausible assumptions. In conclusion, this study suggests, on the basis of currently available data, that denosumab is cost-effective compared with no treatment for postmenopausal Belgian women with low bone mass and who are similar to patients included in the FREEDOM Trial. In addition, denosumab was found to be cost-effective in population currently reimbursed in Europe with T-score < or = -2.5 or prevalent vertebral fracture, aged 60 years and above. Additional data are needed on the relative cost-effectiveness compared with other anti-osteoporotic agents and on the long-term safety of denosumab.

Cost-effectiveness of osteoporosis screening followed by treatment: the impact of medication adherence

OBJECTIVE

To estimate the impact of medication adherence on the cost-effectiveness of mass-screening by bone densitometry followed by alendronate therapy for women diagnosed with osteoporosis.

METHODS

A validated Markov microsimulation model with a Belgian health-care payer perspective and a lifetime horizon was used to assess the cost per quality-adjusted life year (QALY) gained of the screening/treatment strategy compared with no intervention. Real-world adherence to alendronate therapy and full adherence over 5 years were both investigated. The real-world adherence scenario employed adherence data from published observational studies, and medication adherence was divided into persistence, compliance, and primary adherence. Uncertainty was investigated using one-way and probabilistic sensitivity analyses.

RESULTS

At 65 years of age, the costs per QALY gained because of the screening/treatment strategy versus no intervention are euro32,008 and euro16,918 in the real-world adherence and full adherence scenarios, respectively. The equivalent values are euro80,836 and euro40,462 at the age of 55 years, and they decrease to euro10,600 and euro1229 at the age of 75 years. Sensitivity analyses show that the presence of the upfront cost of case finding has a substantial role in the impact of medication adherence on cost-effectiveness.

CONCLUSION

This study indicates that nonadherence with osteoporosis medications substantially increases the incremental cost-effectiveness ratio of osteoporosis screening strategies. All aspects of medication adherence (i.e., compliance, persistence, and primary adherence) should therefore be reported and included in pharmacoeconomic analyses, and especially in the presence of the upfront cost of case finding (such as screening cost).

Cost-effectiveness of strontium ranelate versus risedronate in the treatment of postmenopausal osteoporotic women aged over 75 years

OBJECTIVE

To estimate the cost-effectiveness of strontium ranelate in the treatment of postmenopausal osteoporotic women aged over 75 years.

MATERIALS AND METHODS

A validated Markov microsimulation model with a Belgian payer's perspective estimated the cost per quality-adjusted life-year (QALY) of a 3-year strontium ranelate treatment compared with no treatment and with the bisphosphonate risedronate. Data on the effect of both treatments on fracture risk were taken from the Cochrane Database of Systematic Reviews. Analyses were performed for postmenopausal women aged 75 and 80 years, either with a diagnosis of osteoporosis (i.e. bone mineral density T-score <or=-2.5 SD) or with prevalent vertebral fractures (PVF). Parameter uncertainty was evaluated using both one-way and probabilistic sensitivity analyses.

RESULTS

Strontium ranelate was dominant (i.e. more effective and less costly) versus risedronate for women with osteoporosis aged over 75 years and for women with PVF aged 80 years. The cost per QALY gained of strontium ranelate compared with risedronate at 75 years of age was euro 11,435 for women with PVF. When compared with no treatment, the costs per QALY gained of strontium ranelate were euro 15,588 and euro 7,708 at 75 and 80 years of age for women with osteoporosis; the equivalent values were euro 16,518 and euro 6,015 for women with PVF. Probabilistic sensitivity analyses showed that strontium ranelate was generally more cost-effective than risedronate, in the range of 60% in all cases.

CONCLUSION

The results of this study suggest that strontium ranelate is a cost-effective strategy, in a Belgian setting, for the treatment of postmenopausal osteoporotic women aged over 75 years.