Which screening strategy using BMD measurements would be most cost effective for hip fracture prevention in elderly women? A decision analysis based on a Markov model

Protocol for the models of primary osteoporosis screening in men (MOPS) cluster randomized trial

Current guidelines recommend primary osteoporosis screening for at-risk men to reduce the morbidity, mortality, and cost associated with osteoporotic fractures. However, analyses in a national Veterans Health Administration cohort of over 4,000,000 men demonstrated that primary osteoporosis screening as it is currently operationalized does not benefit most older Veterans due to inefficient targeting and low subsequent treatment and adherence rates. The overall objective of this study is to determine whether a new model of primary osteoporosis screening reduces fracture risk compared to usual care. We are conducting a pragmatic group randomized trial of 38 primary care teams assigned to usual care or a Bone Health Service (BHS) screening model in which screening and adherence activities are managed by a centralized expert team. The study will: 1) compare the impact of the BHS model on patient-level outcomes strongly associated with fracture rates (eligible proportion screened, proportion meeting treatment criteria who receive osteoporosis medications, medication adherence, and femoral neck bone mineral density); 2) quantify the impact on provider and facility-level outcomes including change in DXA volume, change in metabolic bone disease clinic volume, and PACT provider time and satisfaction; and 3) estimate the impact on health system and policy outcomes using Markov models of screening program cost per quality adjusted life year based from health system and societal perspectives.

Prevalence of osteoarthritis in lower middle- and low-income countries: a systematic review and meta-analysis

Evidence from the Global Burden of Disease studies suggests that osteoarthritis (OA) is a significant cause of disability globally; however, it is less clear how much of this burden exists in low-income and lower middle-income countries. This study aims to determine the prevalence of OA in people living in low-income and lower middle-income countries. Four electronic databases (MEDLINE, EMBASE, CINAHL and Web of Science) were systematically searched from inception to October 2018 for population-based studies. We included studies reporting the prevalence of OA among people aged 15 years and over in low-income and lower middle-income countries. The prevalence estimates were pooled across studies using random effects meta-analysis. Our study was registered with PROSPERO, number CRD42018112870.The search identified 7414 articles, of which 356 articles were selected for full text assessment. 34 studies were eligible and included in the systematic review and meta-analysis. The pooled prevalence of OA was 16·05% (95% confidence interval (CI) 12·55-19·89), with studies demonstrating a substantial degree of heterogeneity (I2 = 99·50%). The pooled prevalence of OA was 16.4% (CI 11·60-21.78%) in South Asia, 15.7% (CI 5·31-30·25%) in East Asia and Pacific, and 14.2% (CI 7·95-21·89%) in Sub Saharan Africa. The meta-regression analysis showed that publication year, study sample size, risk of bias score and country-income categories were significantly associated with the variations in the prevalence estimates. The prevalence of OA is high in low-income and lower middle-income countries, with almost one in six of the study participants reported to have OA. With the changing population demographics and the shift to the emergence of non-communicable diseases, targeted public health strategies are urgently needed to address this growing epidemic in the aging population.

Intervals between bone mineral density testing with dual-energy X-ray absorptiometry scans in clinical practice

Intervals between dual-energy X-ray absorptiometry (DXA) scans were evaluated in a large cohort of typical clinical practice. Intensive DXA scanning (intervals < 23 months) decreased substantially, from 16.7% in 2006 to 6.7% in 2015.

INTRODUCTION

Serial dual-energy X-ray absorptiometry (DXA) measurements are suggested for patients at high risk of fractures. However, little is known about how often DXA testing occurs in clinical practice.

METHODS

We examined time intervals between DXA testing for monitoring purpose at two academic medical centers in the US between 2004 and 2017. The primary outcome was the presence of testing intervals < 23 months (termed "intensive DXA testing"). A generalized linear mixed model was used to evaluate the association between selected patient-level clinical factors and intensive DXA testing.

RESULTS

Forty-nine thousand four hundred ninety-four DXA tests from 20,200 patients were analyzed. The mean time interval between scans was 36 ± 21 months. Only 11.1% of the repeated DXA testing met the criterion for intensive testing. The percentage of intensive DXA testing dropped from 16.7% in 2006 to 6.7% in 2015 (p for trend < 0.001). After adjusting for age, gender, number of outpatient visits, and calendar year, correlates of intensive DXA testing included a baseline T-score < -2.5 at any anatomic site (OR, 4.8; 95%CI, 4.0-5.7), active use of drugs for osteoporosis (OR, 1.6; 95%CI, 1.3-1.9), and active use of glucocorticoids (OR, 1.3; 95%CI, 1.2-1.4).

CONCLUSIONS

The predictors of intensive DXA testing suggest that this practice is used preferentially in patients with multiple risk factors and to monitor the response to pharmacotherapy. However, intensive DXA testing has become less common in real-world clinical practice over the last decade. Further studies are required to better define the optimal use of bone mineral density testing in this vulnerable population.

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.

Femur segmentation in DXA imaging using a machine learning decision tree

BACKGROUND

Accurate measurement of bone mineral density (BMD) in dual-energy X-ray absorptiometry (DXA) is essential for proper diagnosis of osteoporosis. Calculation of BMD requires precise bone segmentation and subtraction of soft tissue absorption. Femur segmentation remains a challenge as many existing methods fail to correctly distinguish femur from soft tissue. Reasons for this failure include low contrast and noise in DXA images, bone shape variability, and inconsistent X-ray beam penetration and attenuation, which cause shadowing effects and person-to-person variation.

OBJECTIVE

To present a new method namely, a Pixel Label Decision Tree (PLDT), and test whether it can achieve higher accurate performance in femur segmentation in DXA imaging.

METHODS

PLDT involves mainly feature extraction and selection. Unlike photographic images, X-ray images include features on the surface and inside an object. In order to reveal hidden patterns in DXA images, PLDT generates seven new feature maps from existing high energy (HE) and low energy (LE) X-ray features and determines the best feature set for the model. The performance of PLDT in femur segmentation is compared with that of three widely used medical image segmentation algorithms, the Global Threshold (GT), Region Growing Threshold (RGT), and artificial neural networks (ANN).

RESULTS

PLDT achieved a higher accuracy of femur segmentation in DXA imaging (91.4%) than either GT (68.4%), RGT (76%) or ANN (84.4%).

CONCLUSIONS

The study demonstrated that PLDT outperformed other conventional segmentation techniques in segmenting DXA images. Improved segmentation should help accurate computation of BMD which later improves clinical diagnosis of osteoporosis.

Utilization of bone mineral density testing among breast cancer survivors in British Columbia, Canada

Breast cancer survivors are at high osteoporosis risk. Bone mineral density testing plays a key role in osteoporosis management. We analyzed a historical utilization of bone mineral density testing in breast cancer survivors. The utilization remained low in the 1995-2008 period. Lower socio-economic status and rural residency were associated with lower utilization.

INTRODUCTION

To evaluate the utilization of bone mineral density (BMD) testing for female breast cancer survivors aged 65+ surviving ≥ 3 years in British Columbia, Canada.

METHODS

A retrospecitve population-based data linkage study. Trends in proportion of survivors with ≥ 1 BMD test for each calendar year from 1995 to 2008 were evaluated with a serial cross-sectional analysis. Associations between factors (socio-demographic and clinical) and BMD testing rates over the period 2006-2008 for 7625 survivors were evaluated with a cross-sectional analysis and estimated as adjusted prevalence ratios (PR_adj) using log-binomial models.

RESULTS

Proportions of survivors with ≥ 1 BMD test increased from 1.0% in 1995 to 10.1% in 2008. The BMD testing rate in 2006-2008 was 26.5%. Socio-economic status (SES) and urban/rural residence were associated with BMD testing rates in a dose-dependent relationship (p for trend< 0.01). Survivors with lower SES (PR_adj = 0.66-0.78) or rural residence (PR_adj = 0.70) were 20-30% less likely to have BMD tests, compared with survivors with the highest SES or urban residence. BMD testing rates were also negatively associated with older age (75+) (PR_adj = 0.47; 95% CI = 0.42, 0.52), nursing home residency (0.05; 0.01, 0.39), recent osteoporotic fractures (0.21; 0.14, 0.32), and no previous BMD tests (0.26; 0.23, 0.29).

CONCLUSION

Utilization of BMD testing was low for breast cancer survivors in BC, Canada. Lower SES and rural residence were associated with lower BMD testing rates.

IMPLICATION FOR CANCER SURVIVORS

Female breast cancer survivors, especially those with lower SES or rural residence, should be encouraged to receive BMD tests as recommended by Canadian guidelines.

Bone Density Screening and Re-screening in Postmenopausal Women and Older Men

Clinical practice guidelines universally recommend bone mineral density (BMD) screening to identify osteoporosis in women aged 65 years and older. Risk assessment is recommended to guide BMD screening in postmenopausal women under age 65. Insufficient data are available to inform standard ages to start and stop BMD screening in postmenopausal women. Based on longitudinal studies of incident osteoporosis and fracture in postmenopausal women, an initial BMD test should be ordered for all women aged 65, and the frequency of re-screening should be based on age and BMD T score (more frequent testing for older age and lower T score). Although clinical practice guidelines recommend BMD screening according to risk factors for fracture in postmenopausal women under age 65, no standard approach to risk assessment exists. Minimal evidence is available to guide osteoporosis screening in men, but some experts recommend initiation of BMD screening in men at age 70.

Accounting for increased non-target-disease-specific mortality in decision-analytic screening models for economic evaluation

BACKGROUND

Positive screening results are often associated not only with target-disease-specific but also with non-target-disease-specific mortality. In general, this association is due to joint risk factors. Cost-effectiveness estimates based on decision-analytic models may be biased if this association is not reflected appropriately.

OBJECTIVE

To develop a procedure for quantifying the degree of bias when an increase in non-target-disease-specific mortality is not considered.

METHODS

We developed a family of parametric functions that generate hazard ratios (HRs) of non-target-disease-specific mortality between subjects screened positive and negative, with the HR of target-disease-specific mortality serving as the input variable. To demonstrate the efficacy of this procedure, we fitted a function within the context of coronary artery disease (CAD) risk screening, based on HRs related to different risk factors extracted from published studies. Estimates were embedded into a decision-analytic model, and the impact of 'modelling increased non-target-disease-specific mortality' was assessed.

RESULTS

In 55-year-old German men, based on a risk screening with 5% positively screened subjects, and a CAD risk ratio of 6 within the first year after screening, incremental quality-adjusted life-years were 19% higher and incremental costs were 8% lower if no adjustment was made. The effect varied depending on age, gender, the explanatory power of the screening test and other factors.

CONCLUSION

Some bias can occur when an increase in non-target-disease-specific mortality is not considered when modelling the outcomes of screening tests.

Salivary calcium concentration as a screening tool for postmenopausal osteoporosis

AIM

Measurements of salivary calcium level may be a useful screening tool for osteoporosis in postmenopausal women. The purpose of this study was to clarify whether this measure is valid compared with dual-energy X-ray (Bone Mineral Density) screening tools in osteoporosis.

METHODS

A case-control study was carried out in 40 postmenopausal women with osteoporosis (T-score ≤ -2.5) and 40 women without osteoporosis (T-score > -1 bone mineral density). Salivary samples were collected and calcium concentrations were measured and expressed as mg/dL. Receiver operating characteristic curve analyses was used to determine the optimal cut-off thresholds for salivary calcium in healthy postmenopausal women.

RESULTS

The cut-off point for salivary calcium was 6.1 mg/dL. The sensitivity and specificity, respectively, for identifying women with osteoporosis, were 67.5 (95%CI 52.33-82.67) and 60% (95%CI 44.62-75.38). The area under curve (AUC) was 0.678 (95%CI 0.56-0.79), the positive predictive value (PPV) was 62.79 (95%CI 47.74-77.84) and negative predictive value (NPV) was 64.86% (95%CI 49.27-80.46). The positive likelihood ratio was 1.688 and the negative likelihood ratio was 0.542.

CONCLUSIONS

Salivary calcium concentration discriminates between women with and without osteoporosis and constitutes a useful tool for screening for osteoporosis.

Cost-effectiveness of different strategies for selecting and treating individuals at increased risk of osteoporosis or osteopenia: a systematic review

OBJECTIVES

To compare cost-effectiveness modeling analyses of strategies to prevent osteoporotic and osteopenic fractures either based on fixed thresholds using bone mineral density or based on variable thresholds including bone mineral density and clinical risk factors.

METHODS

A systematic review was performed by using the MEDLINE database and reference lists from previous reviews. On the basis of predefined inclusion/exclusion criteria, we identified relevant studies published since January 2006. Articles included for the review were assessed for their methodological quality and results.

RESULTS

The literature search resulted in 24 analyses, 14 of them using a fixed-threshold approach and 10 using a variable-threshold approach. On average, 70% of the criteria for methodological quality were fulfilled, but almost half of the analyses did not include medication adherence in the base case. The results of variable-threshold strategies were more homogeneous and showed more favorable incremental cost-effectiveness ratios compared with those based on a fixed threshold with bone mineral density. For analyses with fixed thresholds, incremental cost-effectiveness ratios varied from €80,000 per quality-adjusted life-year in women aged 55 years to cost saving in women aged 80 years. For analyses with variable thresholds, the range was €47,000 to cost savings.

CONCLUSIONS

Risk assessment using variable thresholds appears to be more cost-effective than selecting high-risk individuals by fixed thresholds. Although the overall quality of the studies was fairly good, future economic analyses should further improve their methods, particularly in terms of including more fracture types, incorporating medication adherence, and including or discussing unrelated costs during added life-years.

Volumetric DXA (VXA): A new method to extract 3D information from multiple in vivo DXA images

Three-dimensional geometric and structural measurements of the proximal femur are of considerable interest in understanding the strength of the femur and its susceptibility to fracture. Quantitative computed tomography (QCT) with a small voxel size (≤1 mm per side) is the current "gold standard" to examine the macrostructure of the femur, but it has a high effective radiation dose (approximately 2 to 5 mSv) and cost. Volumetric dual-energy X-ray absorptiometry (VXA) uses a commercially available DXA system (Hologic Discovery A) to reconstruct the proximal femur from four DXA scans delivering an effective radiation dose of 0.04 mSv. VXA was compared with QCT (voxel size of 0.29 × 0.29 × 1 mm) in 41 elderly women (age 82 ± 2.4 years) at slices located at the femoral neck and trochanteric regions of interest. For parameters of shape, the femoral neck axis length (FNAL) and the cross-sectional slice area (SA), accuracy and strong linear correlations (r = 0.84 to 0.98) were demonstrated. Similar correlations (r = 0.81 to 0.97) were observed for the density parameters, the cross-sectional bone area (CSA) and volumetric bone mineral density (vBMD). VXA also demonstrated strong correlations (r = 0.76 to 0.99) for the engineering parameters of the minimum, maximum, and polar cross-sectional moments of inertia (CSMIs) and the section modulus (Z). We conclude that VXA is capable of generating a variety of 3D geometric and structural measurements that are highly correlated with QCT in elderly subjects in vivo. Moreover, the VXA measurements can be made with a commercially available DXA device at a very low radiation dose.

Validation of a 5-year risk score of hip fracture in postmenopausal women. The Danish Nurse Cohort Study

SUMMARY

We evaluated the Women's Health Initiative (WHI) hip fracture risk score in 15,648 postmenopausal Danish nurses. The algorithm was well calibrated for Denmark. However, the sensitivity was poor at common decision making thresholds. Obtaining sensitivity better than 80% led to a low specificity of 61.4%.

INTRODUCTION

A new score based on data from the WHI has been designed to predict 5-year risk of hip fracture in postmenopausal women. The performance of the algorithm has not been validated in populations with different lifestyle characteristics and ethnicity. The aim of this study was to test the clinical performance of the algorithm in a large Danish cohort of postmenopausal Caucasian women against hip fracture.

METHODS

The Danish Nurse Cohort is a prospective risk factor and hormone therapy (HT) study established in 1993. Participants in the present analysis were 15,648 postmenopausal nurses. The calibration and diagnostic performance of the WHI algorithm was evaluated using fracture events captured in the Danish National Hospital Registry.

RESULTS

During 5 years of follow-up, 122 participants suffered a hip fracture (1.8/1,000 person years). The WHI algorithm predicted that 107 hip fractures would occur, indicating an underestimation of the number of fractures by 12%. To obtain sensitivity better than 80%, the cut-off value for 5-year risk was set to 0.5%, which was accompanied by a low positive predictive value of 1.9% and a low specificity of 61.4%. The algorithm predicted too many fractures in HT-users (12 observed, 22 expected) and too few in non HT-users (107 observed, 81 expected).

CONCLUSIONS

While the WHI algorithm was well calibrated on the Danish population, the clinical utility of the WHI algorithm in Danish postmenopausal women was limited by poor sensitivity at common decision-making thresholds and suboptimal in non-HT-users.

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 screen-and-treat strategies for low bone mineral density: how do we screen, who do we screen and who do we treat?

Bone densitometry is currently widely recommended for, and considered central to, identifying post-menopausal women and older men at high risk of fracture and establishing an indication for pharmacological fracture-prevention therapy. The purpose of this article is to comprehensively review cost-effectiveness modelling studies published to date of bone mass measurement technologies (primarily dual energy x-ray absorptiometry [DXA]) designed to identify those individuals at sufficiently high risk of fracture to warrant pharmacological fracture-prevention therapy.Based on older paradigms of the pharmacological treatment of those with a bone density value below a specific threshold, bone densitometry appears to be cost effective for post-menopausal women aged > or =65 years, regardless of the presence or absence of other clinical risk factors. For younger post-menopausal women, bone densitometry is likely to be cost effective only for those with specific clinical risk factors, such as prior fracture or low bodyweight. For older men, bone densitometry may be cost effective for those who have had a prior fracture and/or are aged > or =80 years, but the subset of men for whom bone densitometry is likely to be cost effective may vary from country to country depending on societal willingness to pay for health benefits, fracture rates in the population and the costs of bone densitometry and drug treatment. The cost effectiveness of other technologies such as heel ultrasound, peripheral DXA and quantitative CT remains uncertain.However, in the context of the new WHO paradigm of directing treatment based on absolute fracture risk rather than bone density, a new generation of cost-effectiveness modelling studies will be required to define the most cost-effective way bone densitometry can be used to identify those who are likely to benefit sufficiently from pharmacological fracture-prevention therapies.