Age-dependent FRAX-based assessment and intervention thresholds for therapeutic decision making in osteoporosis in the Malaysian population

Fracture risk stratification is crucial in countries with limited access to bone density measurement. 24.8% women were in the high-risk category while 30.4% were in the low-risk category. In the intermediate risk group, after recalculation of fracture risk with bone density, 38.3% required treatment. In more than half, treatment decisions can be made without bone density.

PURPOSE

We aimed to examine the role of age-dependent intervention thresholds (ITs) applied to the Fracture Risk Assessment (FRAX) tool in therapeutic decision making for osteoporosis in the Malaysian population.

METHODS

Data were collated from 1380 treatment-naïve postmenopausal women aged 40-85 years who underwent bone mineral density (BMD) measurements for clinical reasons. Age-dependent ITs, for both major osteoporotic fracture (MOF) and hip fracture (HF), were calculated considering a woman with a BMI of 25 kg/m2, aged between 40 and 85years, with a prior fragility fracture, sans other clinical risk factors. Those with fracture probabilities equal to or above upper assessment thresholds (UATs) were considered to have high fracture risk. Those below the lower assessment thresholds (LATs) were considered to have low fracture risk.

RESULTS

The ITs of MOF and HF ranged from 0.7 to 18% and 0.2 to 8%, between 40 and 85years. The LATs of MOF ranged from 0.3 to 11%, while those of HF ranged from 0.1 to 5.2%. The UATs of MOF and HF were 0.8 to 21.6% and 0.2 to 9.6%, respectively. In this study, 24.8% women were in the high-risk category while 30.4% were in the low-risk category. Of the 44.8% (n=618) in the intermediate risk group, after recalculation of fracture risk with BMD input, 38.3% (237/618) were above the ITs while the rest (n=381, 61.7%) were below the ITs. Judged by the Youden Index, 11.5% MOF probability which was associated with a sensitivity of 0.62 and specificity of 0.83 and 4.0% HF probability associated with a sensitivity of 0.63 and a specificity 0.82 were found to be the most appropriate fixed ITs in this analysis.

CONCLUSION

Less than half of the study population (44.8%) required BMD for osteoporosis management when age-specific assessment thresholds were applied. Therefore, in more than half, therapeutic decisions can be made without BMD based on these assessment thresholds.

The need to distinguish intervention thresholds and diagnostic thresholds in the management of osteoporosis

This position paper of the International Osteoporosis Foundation (IOF) and the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) addresses the rationale for separate diagnostic and intervention thresholds in osteoporosis. We conclude that the current BMD-based diagnostic criteria for osteoporosis be retained whilst clarity is brought to bear on the distinction between diagnostic and intervention thresholds.

Age-dependent assessment thresholds to optimize patient care in a resource-limited setting: an analysis based on the Sri Lankan FRAX model

Age-dependent upper and lower assessment thresholds help categorizing women aged 40 years or more according to their fracture risk, independent of BMD information.

INTRODUCTION

Age-dependent assessment thresholds of the FRAX algorithm help stratifying men and women aged 40 years or more according to their fracture risk. This allows clinicians to decide on those who require interventions without BMD assessment and those who require BMD input for further assessment.

METHODS

Intervention thresholds were defined by 10-year probabilities of a major osteoporotic fracture (MOF) and hip fracture (HF) considering a woman with a BMI of 25.0 kg/m² having a prior fragility fracture but no other clinical risk factors. The lower assessment thresholds (LAT) were set at 0.8 times the 10-year probabilities of a MOF and HF in a woman with a BMI of 25.0 kg/m², without previous fracture or other clinical risk factors. The upper assessment thresholds (UAT) were set at 1.2 times the intervention thresholds of MOF and HF. Fracture probabilities were estimated for the age range of 40-80 years, without BMD input. These values were applied to a group of women who underwent DXA for clinical reasons in a single center.

RESULTS

The LATs of MOF and HF varied from 0.7 to 8.8% and 0.1 to 3.7%, from 40 to 80 years, respectively. The corresponding values for UATs were 2.5 to 21.6% and 0.3 to 8.4%. ITs of MOF and HF varied from 2.1 to 18% and 0.2 to 7%, respectively. When applied to a group of 315 postmenopausal women who underwent DXA for clinical indications, 22.9% of women were above the UATs (high-risk category) while 8.6% were below the LATs (low-risk category). The proportion of women in the intermediate category who require BMD for further assessment was 68.6% (95% CI 59.7 to 77.5%).

CONCLUSIONS

In nearly one-third of women aged 40 years or more, the decision to treat or not to treat can be achieved without BMD estimation. The remaining two-thirds will require a BMD assessment for further evaluation.

Intervention thresholds to identify postmenopausal women with high fracture risk: A single center study based on the Philippines FRAX model

Objectives

This study is designed to estimate appropriate intervention thresholds for the Philippines Fracture Risk Assessment Tool (FRAX) model to identify postmenopausal women with high fracture risk.

Methods

Age dependent intervention thresholds were calculated for a woman of body mass index 25 kg/m² aged 50-80 years with a previous fragility fracture without other clinical risk factors. Fixed thresholds were developed using a database of 1546 postmenopausal women who underwent dual-energy X-ray absorptiometry for clinical reasons. Major and hip fracture risks were estimated using clinical risk factors with and without bone mineral density (BMD) input. Women were categorized to high risk and low risk groups according to the age dependent thresholds. The best cut-points were determined considering the optimum sensitivity and specificity using receiver operating characteristic analysis.

Results

The age dependent intervention thresholds of major fracture risk ranged from 2.8 to 6.9% while hip fracture risk ranged from 0.4 to 3.0% between 50 and 80 years of age. Major fracture threshold of 3.75% and hip fracture threshold of 1.25% were the best fixed thresholds observed and non-inclusion BMD in the fracture risk estimations did not change the values. As a hybrid method, 3% major fracture and 1% hip fracture risks for those < 70 years old and age-dependent thresholds for those aged 70 years and above can be recommended.

Conclusions

The intervention thresholds estimated in the current study can be applied to identify Filipino postmenopausal women with a high fracture risk. Clinicians should decide on the type of thresholds most appropriate.

An assessment of intervention thresholds for very high fracture risk applied to the NOGG guidelines : A report for the National Osteoporosis Guideline Group (NOGG)

The National Osteoporosis Guideline Group (NOGG) has developed intervention thresholds based on FRAX® to characterise patients at high and very high risk of fracture.

INTRODUCTION

Guidelines for the assessment of fracture risk have begun to categorise patients eligible for treatment into high and very high risk of fracture to inform choice of therapeutic approach. The aim of the present study was to develop intervention thresholds based on the hybrid assessment model of NOGG.

METHODS

We examined the impact of intervention thresholds in a simulated cross-sectional cohort of women age 50 years or more from the UK with the distribution of baseline characteristics based on that in the FRAX cohorts. The prevalence of very high risk using the hybrid model was compared with age-dependent thresholds used by the International Osteoporosis Foundation and the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (IOF/ESCEO). The appropriateness of thresholds was tested based on the populations treated with anabolic agents.

RESULTS

With an upper intervention threshold using the IOF/ESCEO criteria, 56% of women age 50 years or more would be characterised at very high risk. This compares with 36% using the IOF/ESCEO criteria and an age-specific intervention threshold over all ages. With an upper intervention threshold of 1.6 times the pre-existing intervention threshold, 10% of women age 50 years or more would be characterised at very high risk. The data from phase 3 studies indicate that most trial participants exposed to romosozumab or teriparatide would fall into the very high-risk category.

CONCLUSIONS

Proposals for FRAX-based criteria for very high risk for the NOGG hybrid model categorise a small proportion of women age 50 years or more (10%) in this highest risk stratum. The level of risk identified was comparable to that of women enrolled in trials of anabolic agents.

Treatment indications and thresholds of intervention: consensus and controversies in osteoporosis

A few indications for treatment and thresholds for intervention in osteoporosis have been propounded in the literature and recommended in guidelines. These include a bone mineral density (BMD) T-score ≤ -2.5, fracture probability-based scores and the presence of a fragility fracture. A low BMD is associated with an increased risk of fracture. However, a BMD T-score of ≤ -2.5 on its own does not capture fracture risk in its entirety. Fracture risk assessment tools that are based on clinical risk factors arose from the misgivings about using BMD T-scores in isolation to assess fracture risk. Algorithms such as FRAX, Garvan etc, integrate various clinical risk factors with or without BMD to compute the probability of a hip fracture or a major osteoporotic fracture over a finite period. These probabilities do not yield distinctive thresholds by themselves and need to be interpreted wisely and adopted by consensus. Evidence exists to show that treatment can decrease the risk of sustaining a second fracture. Therefore, patients with a fragility fracture should be considered for treatment. In this narrative interview, we will explore the strengths and limitations of some of these indications for treatment and will discuss the various points of contention surrounding them.

Cost-effectiveness of FRAX®-based intervention thresholds for management of osteoporosis in Singaporean women

Cost-effectiveness analysis of FRAX® intervention thresholds (ITs) in Singaporean women > 50 years of age showed that generic alendronate was cost-effective at age-dependent major osteoporotic fracture (MOF) IT from the ages of 65 years for both full and real-world adherence whilst hip fracture (HF) ITs were cost-effective from the ages of 60 and 65 years. Alendronate was cost-effective irrespective of age only at fixed MOF IT of 14% and HF IT of 3.5%.

INTRODUCTION

FRAX®-based intervention thresholds (ITs) were recently identified for osteoporosis management in Singapore. This study aimed to assess the cost-effectiveness of ITs in Singaporean women over the age of 50 years.

METHODS

A validated Markov microsimulation model was used to estimate the lifetime healthcare costs (SGD2019) per quality-adjusted life-years (QALY) of generic alendronate compared with no treatment. Cost-effectiveness of age-dependent FRAX® major osteoporotic fracture (MOF) and hip fracture (HF) ITs was explored. In addition, ITs that would lead to cost-effectiveness were computed. Fracture incidence and cost data were obtained from the Ministry of Health and a previously published Singaporean study. A cost-effectiveness threshold of SGD 62,500/QALY gained was used, based conservatively on 0.7 times the Singapore GDP per capita.

RESULTS

Generic alendronate was shown to be cost-effective at MOF ITs from the ages of 65 years, while HF ITs were cost-effective from the ages of 60 and 65 years, assuming full and real-world adherence, respectively. A 14% MOF and a 3.5% HF ITs were required for alendronate to be cost-effective above 50 years.

CONCLUSION

This study suggests that the treatment of Singaporean women with alendronate is cost-effective at age-dependant FRAX® intervention thresholds at 65 years and older. Furthermore, identifying women at any age above 50 years with a 10-year risk of MOF or HF of 14% or 3.5% would lead to efficient use of resources. Cost-effective access to therapy for patients at high fracture probability based on FRAX® could contribute to reduce the growing burden of osteoporotic fractures in Singapore.

Novel algorithm generating strategy to identify high fracture risk population using a hybrid intervention threshold

INTRODUCTION

The aim of this study was to develop an algorithm to identify high-risk populations of fragility fractures in Taiwan.

MATERIALS AND METHODS

A total of 16,539 postmenopausal women and men (age ≥ 50 years) were identified from the Taiwan Osteoporosis Survey database. Using the Taiwan FRAX^® tool, the 10-year probability of major osteoporotic fracture (MOF) and hip fracture (HF) and the individual intervention threshold (IIT) of each participant were calculated. Subjects with either a probability above the IIT or those with MOF ≥ 20% or HF ≥ 9% were included as group A. Subjects with a bone mineral density (BMD) T-score at femoral neck based on healthy subjects of ≤ - 2.5 were included in group B. We tested several cutoff points for MOF and HF so that the number of patients in group A and group B were similar. A novel country-specific hybrid intervention threshold along with an algorithm was generated to identify high fracture risk individuals.

RESULTS

3173 (19.2%) and 3129 (18.9%) participants were categorized to groups A and B, respectively. Participants in group B had a significantly lower BMD (p < 0.001), but clinical characteristics, especially the 10-year probability of MOF (p < 0.001) or HF (p < 0.001), were significantly worse in group A. We found the algorithm generated from the hybrid intervention threshold is practical.

CONCLUSION

The strategy of generating an algorithm for fracture prevention by novel hybrid intervention threshold is more efficient as it identifies patients with a higher risk of fragility fracture and could be a template for other country-specific policies.

A decade of FRAX: how has it changed the management of osteoporosis?

The fracture risk assessment tool, FRAX^®, was released in 2008 and provides country-specific algorithms for estimating individualized 10-year probability of hip and major osteoporotic fracture (hip, clinical spine, distal forearm, and proximal humerus). Since its release, 71 models have been made available for 66 countries covering more than 80% of the world population. The website receives approximately 3 million visits annually. Following independent validation, FRAX has been incorporated into more than 80 guidelines worldwide. The application of FRAX in assessment guidelines has been heterogeneous with the adoption of several different approaches in setting intervention thresholds. Whereas most guidelines adopt a case-finding strategy, the case for FRAX-based community screening in the elderly is increasing. The relationship between FRAX and efficacy of intervention has been explored and is expected to influence treatment guidelines in the future.

FRAX: re-adjust or re-think

Since its development in 2008, FRAX has booked its place in the standard day to day management of osteoporosis. The FRAX tool has been appreciated for its simplicity and applicability for use in primary care, but criticised for the same reason, as it does not take into account exposure response. To address some of these limitations, relatively simple arithmetic procedures have been proposed to be applied to the conventional FRAX estimates of hip and major fracture probabilities aiming at adjustment of the probability assessment. However, as the list of these adjustments got longer, this has reflected on its implementation in the standard practice and gave FRAX a patchy look. Consequently, raises the need to re-think of the current FRAX and whether a second generation of the tool is required to address the perceived limitations of the original FRAX. This article will discuss both point of views of re-adjustment and re-thinking.

The diversity of Fracture Risk Assessment Tool (FRAX)-based intervention thresholds in Asia

Fracture Risk Assessment Tool (FRAX), introduced in 2008, is the most frequently used fracture risk calculator. Many Asian countries have developed own FRAX models to suit their country needs. Only a few Asian countries, however, have developed country-specific intervention thresholds to demarcate high-risk patients. A wide variation is seen in these intervention thresholds partly due to the different approaches used in developing the cutoff values. This paper discusses the diversity of the intervention thresholds in Asian countries and possible reasons. It also discusses the future directions for the countries in the Asian region.

Revised FRAX®-based intervention thresholds for the management of osteoporosis among postmenopausal women in Sri Lanka

This paper revised the fixed intervention thresholds (ITs) based on the Sri Lankan fracture risk assessment tool (FRAX) published in 2013 and introduced new ITs, hybrid and two-tier, aiming to help clinicians in the management of postmenopausal osteoporosis. The hybrid and two-tier ITs have a better discriminatory power than age-dependent and revised fixed ITs.

INTRODUCTION

This study revised the Sri Lankan FRAX®-based intervention thresholds (ITs) previously published in 2013.

METHOD

Age-dependent ITs were estimated, from 50-80 years with 5-year intervals, using a Sri Lankan FRAX® algorithm for a woman with a BMI of 24.8 kg/m² and history of prior fragility fracture without other clinical risk factors. Data of 653 postmenopausal women were used in estimating fixed, hybrid, and two-tier ITs. ITs were determined using the ROC curve and partial Youden index. New ITs were validated using data of 356 postmenopausal women who underwent DXA and 62 women who had a recent fragility fracture. Women in the two groups (n = 653 and n = 356) came from the Southern Province and had undergone DXA in our state-owned tertiary care hospital as a part of their routine clinical assessment.

RESULTS

The mean (SD) age and BMI of the subjects (n = 653) were 62 (8) years and 24.8 (1.2) kg/m², respectively. Age-dependent ITs of major osteoporotic fracture risk (MOFR) and hip fracture risk (HFR) ranged from 2.7 to 18% and from 0.4 to 7.1%. The best fixed ITs for women aged 50-80 years were 9% for MOFR and 3% for HFR. In the hybrid method, MOFR of 6% and HFR of 2% were found appropriate for women aged < 70 years. These were combined with age-dependent ITs for women aged 70 years and above. In the two-tier system, two sets of ITs were calculated (ITs of MOFR/HFR for women aged < 70 years and ≥ 70 years were 6%/2% and 12%/5%, respectively). When age-dependent ITs were considered the reference standard, sensitivities of the fixed, hybrid, and two-tier ITs were 0.63, 0.73, and 0.74, respectively. The specificities were 0.76, 0.86, and 0.80 in the same order. Sensitivities of the age-dependent, fixed, hybrid, and two-tier ITs in identifying a woman with an incident fracture were 26%, 48%, 61%, and 61%, respectively.

CONCLUSIONS

The new fixed MOFR is slightly lower than the previous value and hybrid and two-tier ITs perform better than age-dependent and fixed ITs.

Cost-effective but clinically inappropriate: new NICE intervention thresholds in osteoporosis (Technology Appraisal 464)

PURPOSE

To comment on the latest technology appraisal of the National Institute for Clinical Excellence (NICE) in osteoporosis.

METHODS

Review of NICE Technology Appraisal (TA464) on bisphosphonate use in osteoporosis.

RESULTS

The NICE appraisal on bisphosphonate use in osteoporosis indicates that treatment with oral bisphosphonates may be instituted at a FRAX 10-year probability of major osteoporotic fracture above 1%. Implementation would mean that all women aged 50 years or older are deemed eligible for treatment, a position that would increase the burden of rare long-term side effects across the population.

CONCLUSION

Cost-effectiveness thresholds for low-cost interventions should not be used to set intervention thresholds but rather to validate the implementation of clinically driven intervention thresholds.

Review of the guideline of the American College of Physicians on the treatment of osteoporosis

This review, endorsed by the International Osteoporosis Foundation and the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases, summarizes several failings of the recent guidelines of the American College of Physicians (ACP) on the treatment of low bone density or osteoporosis to prevent fractures.

INTRODUCTION

The ACP recently issued guidelines for the treatment of low bone density or osteoporosis to prevent fractures.

METHODS

Literature review and critical review of the ACP guidelines.

RESULTS

The guideline is lacking in scope due to the endorsement of treatment based on T-scores rather than fracture risk assessment and in failure to adequately consider anabolic therapies.

CONCLUSIONS

The ACP guideline appears outdated.

Cost-Effectiveness of Intervention Thresholds for the Treatment of Osteoporosis Based on FRAX(®) in Portugal

Cost-effective intervention thresholds (ITs) based on FRAX(®) were determined for Portugal. Assuming a willingness to pay (WTP) of €32,000 per quality-adjusted life years (QALYs), treatment with generic alendronate is cost effective for men and women aged 50 years or more, with 10-year probabilities for major osteoporotic fractures and hip above 8.8 and 2.5 %, respectively. The aim of the present study was to identify the 10-year probabilities of a major and hip osteoporotic fracture using FRAX(®) validated for Portugal, above which pharmacologic interventions become cost effective in the Portuguese context. A previously developed and validated state transition Markov cohort model was populated with epidemiologic, economic and quality-of-life fracture data from Portugal. Cost-effectiveness of FRAX(®)-based ITs was calculated for generic alendronate and proprietary zoledronic acid, denosumab and teriparatide were compared to "no intervention", assuming a WTP of €32,000 (two times national Gross Domestic Product per capita) per QALYs. In the Portuguese epidemiological and economic context, treatment with generic alendronate was cost effective for men and women aged 50 years or more, with 10-year probabilities at or above 8.8 % for major osteoporotic fractures and 2.5 % for hip fractures. Cost-effective threshold 10-year probabilities for major osteoporotic and hip fractures were higher for zoledronic acid (20.4 and 10.1 %), denosumab (34.9 and 10.1 %) and teriparatide (77.8 and 62.6 %), respectively. A tool is provided to perform the calculation of cost-effective ITs for different medications, according to age group and diverse levels of WTP. Cost-effective ITs, for different medications, age groups and WTP, based on 10-year probabilities of major and hip fracture probabilities calculated with FRAX are provided.