Development and application of FRAX in the management of osteoporosis in Ireland

Ireland DXA-FRAX may differ significantly and substantially to Web-FRAX

Appropriate use of FRAX reduces the number of people requiring DXA scans, while contemporaneously determining those most at risk. We compared the results of FRAX with and without inclusion of BMD. It suggests clinicians to carefully consider the importance of BMD inclusion in fracture risk estimation or interpretation in individual patients.

PURPOSE

FRAX is a widely accepted tool to estimate the 10-year risk of hip and major osteoporotic fracture in adults. Prior calibration studies suggest this works similarly with or without the inclusion of bone mineral density (BMD). The purpose of the study is to compare within-subject differences between FRAX estimations derived using DXA and Web software with and without the inclusion of BMD.

METHOD

A convenience cohort was used for this cross-sectional study, consisting of 1254 men and women aged between 40 and 90 years who had a DXA scan and complete validated data available for analysis. FRAX 10-year estimations for hip and major osteoporotic fracture were calculated using DXA software (DXA-FRAX) and the Web tool (Web-FRAX), with and without BMD. Agreements between estimates within each individual subject were examined using Bland-Altman plots. We performed exploratory analyses of the characteristics of those with very discordant results.

RESULTS

Overall median DXA-FRAX and Web-FRAX 10-year hip and major osteoporotic fracture risk estimations which include BMD are very similar: 2.9% vs. 2.8% and 11.0% vs. 11% respectively. However, both are significantly lower than those obtained without BMD: 4.9% and 14% respectively, P < 0.001. Within-subject differences between hip fracture estimates with and without BMD were < 3% in 57% of cases, between 3 and 6% in 19% of cases, and > 6% in 24% of cases, while for major osteoporotic fractures such differences are < 10% in 82% of cases, between 10 and 20% in 15% of cases, and > 20% in 3% of cases.

CONCLUSIONS

Although there is excellent agreement between the Web-FRAX and DXA-FRAX tools when BMD is incorporated, sometimes there are very large differences for individuals between results obtained with and without BMD. Clinicians should carefully consider the importance of BMD inclusion in FRAX estimations when assessing individual patients.

Osteoporotic fracture admissions compared to other major medical admissions in Irish public hospitals

Multinational reports suggest Ireland has one of the greatest illness burdens related to osteoporosis. Hospital care represents the costliest portion of health services. We found public hospital bed days for fragility fractures in Ireland increased by 43% between 2008 and 2017 which exceeded those for other common diseases.

INTRODUCTION

Recent multinational reports suggest Ireland has one of the greatest illness burdens related to osteoporosis, manifesting clinically as fragility fractures (FF). International reports show that FF incidence, rate of hospital admission and cost are similar or greater than those for breast cancer, myocardial infarction and stroke. Studies addressing the illness burden of osteoporosis in Ireland are few, and none compares fragility fractures to other common chronic diseases.

METHODS

A retrospective analysis of national administrative data for all public hospital admissions was performed on adults aged 50 years and older from January 2008 to December 2017.

RESULTS

In 2017, public hospital bed days for FF totalled 249,887 outnumbering Chronic Obstructive Pulmonary Disease (COPD): 131,897; 6 solid cancers (CA): 118,098; myocardial infarction (MI): 83,477; and diabetes mellitus (DM): 31,044. Bed days for FF increased by 43% between 2008 and 2017, in contrast to a 32%, 28% and 31% reduction for CA, MI and DM, respectively, and a 12% increase for COPD. Public hospital bed days for FF in 2016 were greater than MI, stroke, atrial fibrillation and chest pain combined but less than a combination of COPD, pneumonia and lower respiratory tract infection.

CONCLUSION

Osteoporotic fractures represent a large and rapidly increasing illness burden amongst older Irish adults, with substantial care requirements and the resulting onus on our healthcare system. Urgent action is needed to address this public health issue and the services for those at risk of fracture.

Accuracy of Opportunistic Bone Mineral Density Assessment on Staging Computed Tomography for Gynaecological Cancers

Background and Objectives: Women with gynecological cancers constitute a high-risk cohort for loss of bone density. International guidance stipulates women undergoing cancer treatments associated with bone loss should have a quantitative assessment of bone density. Access to Dual-energy X-ray Absorptiometry (DXA) is limited. This study aimed to assess the accuracy of opportunistic bone density measurement on staging computed tomography (CT) scans for gynaecological malignancies, in comparison to the gold standard DXA. Materials and Methods: Women with a staging CT scan of the abdomen and pelvis for a new diagnosis of gynecological cancer were recruited. DXA was performed within 6 weeks of treatment for gynaecological cancer. Lumbar bone density was measured by CT attenuation values, in Hounsfield units (HU), of the anterior trabecular region. Correlations between CT and DXA parameters were analysed. Receiver Operating Characteristic(ROC) curves for diagnosis of low bone density and osteoporosis were analysed. Results: Final cohort included 48 of 50 women recruited. There was good diagnostic accuracy for abnormal bone density and osteoporosis, with areas under the ROC curve at L1 of 0.77 (p = 0.002) and 0.80 (p = 0.020) respectively. CT-HU of 170-190 yielded sensitivities of 87-90%, positive predictive values of 75-84% and negative predictive values of 71-75% for the diagnosis of low bone mineral density. CT-HU of 90-110 yielded specificities of 85-93% for the diagnosis of osteoporosis. Moderate correlations were found between CT-HU and both DXA T-scores and diagnostic categories. Conclusions: This is the first study to assess the opportunistic application of CT in the assessment of bone health in women with gynaecological cancer, a cohort at high-risk of osteoporosis. The correlation between bone density assessment in CT-HU and DXA, and strong AUC values for the diagnosis of low bone density (0.77) and osteoporosis (0.80) support this pragmatic solution in resolving the care-gap in cancer treatment-induced bone loss, often associated with poor access to DXA.

Machine Learning Can Improve Clinical Detection of Low BMD: The DXA-HIP Study

BACKGROUND

Identification of those at high risk before a fracture occurs is an essential part of osteoporosis management. This topic remains a significant challenge for researchers in the field, and clinicians worldwide. Although many algorithms have been developed to either identify those with a diagnosis of osteoporosis or predict their risk of fracture, concern remains regarding their accuracy and application. Scientific advances including machine learning methods are rapidly gaining appreciation as alternative techniques to develop or enhance risk assessment and current practice. Recent evidence suggests that these methods could play an important role in the assessment of osteoporosis and fracture risk.

METHODS

Data used for this study included Dual-energy X-ray Absorptiometry (DXA) bone mineral density and T-scores, and multiple clinical variables drawn from a convenience cohort of adult patients scanned on one of 4 DXA machines across three hospitals in the West of Ireland between January 2000 and November 2018 (the DXA-Heath Informatics Prediction Cohort). The dataset was cleaned, validated and anonymized, and then split into an exploratory group (80%) and a development group (20%) using the stratified sampling method. We first established the validity of a simple tool, the Osteoporosis Self-assessment Tool Index (OSTi) to identify those classified as osteoporotic by the modified International Society for Clinical Densitometry DXA criteria. We then compared these results to seven machine learning techniques (MLTs): CatBoost, eXtreme Gradient Boosting, Neural network, Bagged flexible discriminant analysis, Random forest, Logistic regression and Support vector machine to enhance the discrimination of those classified as osteoporotic or not. The performance of each prediction model was measured by calculating the area under the curve (AUC) with 95% confidence interval (CI), and was compared against the OSTi.

RESULTS

A cohort of 13,577 adults aged ≥40 yr at the age of their first scan was identified including 11,594 women and 1983 men. 2102 (18.13%) females and 356 (17.95%) males were identified with osteoporosis based on their lowest T-score. The OSTi performed well in our cohort in both men (AUC 0.723, 95% CI 0.659-0.788) and women (AUC 0.810, 95% CI 0.787-0.833). Four MLTs improved discrimination in both men and women, though the incremental benefit was small. eXtreme Gradient Boosting showed the most promising results: +4.5% (AUC 0.768, 95% CI 0.706-0.829) for men and +2.3% (AUC 0.833, 95% CI 0.812-0.853) for women. Similarly MLTs outperformed OSTi in sensitivity analyses-which excluded those subjects taking osteoporosis medications-though the absolute improvements differed.

CONCLUSION

The OSTi retains an important role in identifying older men and women most likely to have osteoporosis by bone mineral density classification. MLTs could improve DXA detection of osteoporosis classification in older men and women. Further exploration of MLTs is warranted in other populations, and with additional data.

The Irish dual-energy X-ray absorptiometry (DXA) Health Informatics Prediction (HIP) for Osteoporosis Project

PURPOSE

The purpose of the Irish dual-energy X-ray absorptiometry (DXA) Health Informatics Prediction (HIP) for Osteoporosis Project is to create a large retrospective cohort of adults in Ireland to examine the validity of DXA diagnostic classification, risk assessment tools and management strategies for osteoporosis and osteoporotic fractures for our population.

PARTICIPANTS

The cohort includes 36 590 men and women aged 4-104 years who had a DXA scan between January 2000 and November 2018 at one of 3 centres in the West of Ireland.

FINDINGS TO DATE

36 590 patients had at least 1 DXA scan, 6868 (18.77%) had 2 scans and 3823 (10.45%) had 3 or more scans. There are 364 unique medical disorders, 186 unique medications and 46 DXA variables identified and available for analysis. The cohort includes 10 349 (28.3%) individuals who underwent a screening DXA scan without a clear fracture risk factor (other than age), and 9947 (27.2%) with prevalent fractures at 1 of 44 skeletal sites.

FUTURE PLANS

The Irish DXA HIP Project plans to assess current diagnostic classification and risk prediction algorithms for osteoporosis and fractures, identify the risk predictors for osteoporosis and develop novel, accurate and personalised risk prediction tools, by using the large multicentre longitudinal follow-up cohort. Furthermore, the dataset may be used to assess, and possibly support, multimorbidity management due to the large number of variables collected in this project.

A brief history of FRAX

This paper reviews the research programme that went into the development of FRAX® and its impact in the 10 years since its release in 2008.

INTRODUCTION

Osteoporosis is defined on the measurement of bone mineral density though the clinical consequence is fracture. The sensitivity of bone mineral density measurements for fracture prediction is low, leading to the development of FRAX to better calculate the likelihood of fracture and target anti-osteoporosis treatments.

METHODS

The method used in this paper is literature review.

RESULTS

FRAX, developed over an 8-year period, was launched in 2008. Since the launch of FRAX, models have been made available for 64 countries and in 31 languages covering more than 80% of the world population.

CONCLUSION

FRAX provides an advance in fracture risk assessment and a reference technology platform for future improvements in performance characteristics.

Worldwide Fracture Prediction

The substantial increase in the burden of non-communicable diseases in general and osteoporosis in particular, necessitates the establishment of efficient and targeted diagnosis and treatment strategies. This chapter reviews and compares different tools for osteoporosis screening and diagnosis; it also provides an overview of different treatment guidelines adopted by countries worldwide. While access to dual-energy X-ray absorptiometry to measure bone mineral density (BMD) is limited in most areas in the world, the introduction of risk calculators that combine risk factors, with or without BMD, have resulted in a paradigm shift in osteoporosis screening and management. To-date, forty eight risk assessment tools that allow risk stratification of patients are available, however only few are externally validated and tested in a population-based setting. These include Osteoporosis Self-Assessment Tool; Osteoporosis Risk Assessment Instrument; Simple Calculated Osteoporosis Risk Estimation; Canadian Association of Radiologists and Osteoporosis Canada calculator; Fracture Risk Assessment Calculator (FRAX); Garvan; and QFracture. These tools vary in the number of risk factors incorporated. We present a detailed analysis of the development, characteristics, validation, performance, advantages and limitations of these tools. The World Health Organization proposes a dual-energy X-ray absorptiometry-BMD T-score ≤ -2.5 as an operational diagnostic threshold for osteoporosis, and many countries have also adopted this cut-off as an intervention threshold in their treatment guidelines. With the introduction of the new fracture assessment calculators, many countries chose to include fracture risk as one of the major criteria to initiate osteoporosis treatment. Of the 52 national guidelines identified in 36 countries, 30 included FRAX derived risk in their intervention threshold and 22 were non-FRAX based.  No universal tool or guideline approach will address the needs of all countries worldwide.  Osteoporosis screening and management guidelines are best tailored according to the needs and resources of individual counties. While few countries have succeeded in generating valuable epidemiological data on osteoporotic fractures, to validate their risk calculators and base their guidelines, many have yet to find the resources to assess variations and secular trends in fractures, the performance of various calculators, and ultimately adopt the most convenient care pathway algorithms.

Assessing Risk of Osteoporotic Fractures in Primary Care: Development and Validation of the FRA-HS Algorithm

We aimed to develop and validate the FRActure Health Search (FRA-HS) score for prediction of risk of osteoporotic fractures in primary care in Italy. We selected a cohort of patients aged 40 years between 1999 and 2002. They were followed until the occurrence of osteoporotic fracture, death, end of data registration, or end of data availability (December 31, 2012). Age, sex, history of osteoporotic fractures, secondary osteoporosis, long-term use of corticosteroids, rheumatoid arthritis, body mass index, smoking, and alcohol abuse/alcohol-related diseases, and the interaction terms sex*use of corticosteroids and age*secondary osteoporosis were entered in a competing-risk regression (Fine and Gray method) to predict the risk of hip/femur or overall major osteoporotic fractures. The coefficients were combined to obtain the FRA-HS for individual patients. Explained variance, discrimination, and calibration measures were computed to evaluate the models accuracy. The final model was tested using an independent data source. The FRA-HS explained 47.36 and 20.6% of the variation for occurrence of hip/femur and overall major osteoporotic fractures, respectively. Area Under Curve was 0.77 and 0.73, respectively. Predicted/observed ratios revealed a margin of error lower than 30% in the 80% of the population. After stratifying by sex, prediction models for hip/femur fractures confirmed acceptable accuracy in both sexes, while poor explained variance (<20%) was observed for overall major fractures. These findings indicate that FRA-HS might be implemented in primary care for risk prediction of hip/femur fractures. General practitioners could be therefore supported by this tool in clinical decision making.

Diagnosis and therapy of osteoporosis in geriatric trauma patients: an update

Demographic changes confront clinicians with an increasing number of orthogeriatric patients. These patients present with comorbidities, which force their surgeons to take into consideration their medical condition. A major risk factor for fractures in orthogeriatric patients is osteoporosis in combination with frailty. To prevent subsequent fractures in these patients, we need to pay attention to adequate osteoporosis treatment in orthogeriatric patients. There is a huge treatment gap. In Germany, 77% of patients with osteoporosis are not treated adequately. Even after fragility fractures, a low percentage of patients receive a specific osteoporosis therapy. Secondary prevention is of great importance in the treatment of these patients. Diagnostics and treatment should be already initiated with the admission to the hospital. Treatment decisions need to be made individually based on the risk profile of the patients. After discharge, it is important to involve the patients’ general practitioners and to follow up on patients regularly to improve their compliance and to ensure adequate therapy. Establishing a fracture liaison service helps coordinating osteoporosis treatment during hospitalization and after discharge. Subsequent fractures can be reduced; therefore, it is an effective service for secondary prevention. The present article provides an overview of how an efficient identification and subsequent treatment of osteoporosis can be achieved in aged trauma patients.

A systematic review of intervention thresholds based on FRAX : A report prepared for the National Osteoporosis Guideline Group and the International Osteoporosis Foundation

This systematic review identified assessment guidelines for osteoporosis that incorporate FRAX. The rationale for intervention thresholds is given in a minority of papers. Intervention thresholds (fixed or age-dependent) need to be country-specific.

INTRODUCTION

In most assessment guidelines, treatment for osteoporosis is recommended in individuals with prior fragility fractures, especially fractures at spine and hip. However, for those without prior fractures, the intervention thresholds can be derived using different methods. The aim of this report was to undertake a systematic review of the available information on the use of FRAX® in assessment guidelines, in particular the setting of thresholds and their validation.

METHODS

We identified 120 guidelines or academic papers that incorporated FRAX of which 38 provided no clear statement on how the fracture probabilities derived are to be used in decision-making in clinical practice. The remainder recommended a fixed intervention threshold (n = 58), most commonly as a component of more complex guidance (e.g. bone mineral density (BMD) thresholds) or an age-dependent threshold (n = 22). Two guidelines have adopted both age-dependent and fixed thresholds.

RESULTS

Fixed probability thresholds have ranged from 4 to 20 % for a major fracture and 1.3-5 % for hip fracture. More than one half (39) of the 58 publications identified utilised a threshold probability of 20 % for a major osteoporotic fracture, many of which also mention a hip fracture probability of 3 % as an alternative intervention threshold. In nearly all instances, no rationale is provided other than that this was the threshold used by the National Osteoporosis Foundation of the USA. Where undertaken, fixed probability thresholds have been determined from tests of discrimination (Hong Kong), health economic assessment (USA, Switzerland), to match the prevalence of osteoporosis (China) or to align with pre-existing guidelines or reimbursement criteria (Japan, Poland). Age-dependent intervention thresholds, first developed by the National Osteoporosis Guideline Group (NOGG), are based on the rationale that if a woman with a prior fragility fracture is eligible for treatment, then, at any given age, a man or woman with the same fracture probability but in the absence of a previous fracture (i.e. at the 'fracture threshold') should also be eligible. Under current NOGG guidelines, based on age-dependent probability thresholds, inequalities in access to therapy arise especially at older ages (≥70 years) depending on the presence or absence of a prior fracture. An alternative threshold using a hybrid model reduces this disparity.

CONCLUSION

The use of FRAX (fixed or age-dependent thresholds) as the gateway to assessment identifies individuals at high risk more effectively than the use of BMD. However, the setting of intervention thresholds needs to be country-specific.

Establishing and evaluating FRAX® probability thresholds in Taiwan

BACKGROUND/PURPOSE

The Taiwanese FRAX^® calculator was launched in 2010. However, cost-effectiveness thresholds for the prescription of antiosteoporosis medications were not established. This study aims to establish and evaluate FRAX^®-based probability thresholds in Taiwan.

METHODS

Using previous data from Taiwan and literature, we determined cost-effectiveness thresholds for prevention of osteoporotic fractures by alendronate with a Markov model, as well as using two other translational approaches. Sensitivity analysis was applied using different alendronate prices. A clinical sample was used to test these Taiwan-specific thresholds by determining the percentages of high-risk patients who would be qualified for current National Health Insurance reimbursement.

RESULTS

With the Markov model, the intervention threshold for hip fracture was 7% for women and 6% for men; for major osteoporotic fracture, it was 15% for women and 12.5% for men. Both translational approach models were cost effective only for certain age groups. However, if branded alendronate was reimbursed at 60% of the current price, they became cost effective in almost all age groups. This clinical screening study showed that the National Health Insurance Administration model identified the highest proportion (44%) of patients qualified for National Health Insurance reimbursements, followed by the Markov model (30%), and the United States model (22%).

CONCLUSION

Three FRAX^®-based models of alendronate use were established in Taiwan to help optimize treatment strategies. The government is encouraged to incorporate FRAX^®-based approaches into the reimbursement policy for antiosteoporosis medicines.

Burden of high fracture probability worldwide: secular increases 2010-2040

The number of individuals aged 50 years or more at high risk of osteoporotic fracture worldwide in 2010 was estimated at 158 million and is set to double by 2040.

INTRODUCTION

The aim of this study was to quantify the number of individuals worldwide aged 50 years or more at high risk of osteoporotic fracture in 2010 and 2040.

METHODS

A threshold of high fracture probability was set at the age-specific 10-year probability of a major fracture (clinical vertebral, forearm, humeral or hip fracture) which was equivalent to that of a woman with a BMI of 24 kg/m(2) and a prior fragility fracture but no other clinical risk factors. The prevalence of high risk was determined worldwide and by continent using all available country-specific FRAX models and applied the population demography for each country.

RESULTS

Twenty-one million men and 137 million women had a fracture probability at or above the threshold in the world for the year 2010. The greatest number of men and women at high risk were from Asia (55 %). Worldwide, the number of high-risk individuals is expected to double over the next 40 years.

CONCLUSION

We conclude that individuals with high probability of osteoporotic fractures comprise a very significant disease burden to society, particularly in Asia, and that this burden is set to increase markedly in the future. These analyses provide a platform for the evaluation of risk assessment and intervention strategies.