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

Performance of Fracture Risk Assessment Tools by Race and Ethnicity: A Systematic Review for the ASBMR Task Force on Clinical Algorithms for Fracture Risk

The American Society of Bone and Mineral Research (ASBMR) Professional Practice Committee charged an ASBMR Task Force on Clinical Algorithms for Fracture Risk to review the evidence on whether current approaches for differentiating fracture risk based on race and ethnicity are necessary and valid. To help address these charges, we performed a systematic literature review investigating performance of calculators for predicting incident fractures within and across race and ethnicity groups in middle-aged and older US adults. We included English-language, controlled or prospective cohort studies that enrolled US adults aged >40 years and reported tool performance predicting incident fractures within individual race and ethnicity groups for up to 10 years. From 4838 identified references, six reports met eligibility criteria, all in women. Just three, all from one study, included results in non-white individuals. In these three reports, non-white women experienced relatively few major osteoporotic fractures (MOFs), especially hip fractures, and risk thresholds for predicting fractures in non-white women were derived from risks in the overall, predominantly white study population. One report suggested the Fracture Risk Assessment Tool (FRAX) without bone mineral density (BMD) overestimated hip fracture similarly across race and ethnicity groups (black, Hispanic, American Indian, Asian, white) but overestimated MOF more in non-white than White women. However, these three reports were inconclusive regarding whether discrimination of FRAX or the Garvan calculator without BMD or of FRAX with BMD for MOF or hip fracture differed between white versus black women. This uncertainty was at least partly due to imprecise hip fracture estimates in black women. No reports examined whether ratios of observed to predicted hip fracture risks within each race or ethnicity group varied across levels of predicted hip fracture risk. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR). This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Composite Outcomes in Clinical Prediction Modeling: Are We Trying to Predict Apples and Oranges?

Composite outcomes are widely used in clinical research. Existing literature has considered the pros and cons of composite outcomes in clinical trials, but their extensive use in clinical prediction has received much less attention. Clinical prediction assists decision-making by directing patients with higher risks of adverse outcomes toward interventions that provide the greatest benefits to those at the greatest risk. In this article, we summarize our existing understanding of the advantages and disadvantages of composite outcomes, consider how these relate to clinical prediction, and highlight the problem of key predictors having markedly different associations with individual components of the composite outcome. We suggest that a "composite outcome fallacy" may occur when a clinical prediction model is based on strong associations between key predictors and one component of a composite outcome (such as mortality) and used to direct patients toward intervention when these predictors actually have an inverse association with a more relevant component of the composite outcome (such as the use of a lifesaving intervention). We propose that clinical prediction scores using composite outcomes should report their accuracy for key components of the composite outcome and examine for inconsistencies among predictor variables.

Evaluation of FRAX Performance Without Bone Mineral Density Calibrated for Mexico to Recognize Women at Risk of Fragility Fractures in Routine Clinical Care

OBJECTIVE

To evaluate FRAX clinical performance without bone mineral density (BMD) to approach people with fracture risk.

METHODS

A cross-sectional study was carried out from July 2012 to February 2020 at outpatient clinic of rheumatology in 2 public hospitals. Postmenopausal women between 40 and 90 years of age were chosen if no previous osteoporosis treatment was received and had femoral neck BMD determination. Clinical performance of FRAX without BMD was evaluated using agreement and diagnostic test statistics.

RESULTS

Four hundred seventy-seven women with a mean age of 62.85 years were included. FRAX without BMD classified 46.03% of them at low risk, 45.82% intermediate risk, and 8.16% high risk. When BMD was included, 17.19% of them revealed high risk. Not incorporating BMD value in the risk assessed a higher percentage of error in the fracture risk classification in high-risk patients; otherwise, including BMD reclassified it as risk below treatment threshold in 20.51% of the patients. The percentage of agreement between the recommendations based on FRAX with and without BMD was 94.98%. Agreement between FRAX score with or without BMD was good to very good (κ = 0.79, Gwet = 0.93). FRAX without BMD presented a positive predictive value of 79.5% and negative predictive value of 97.7%.

CONCLUSIONS

FRAX without BMD correctly classified most women evaluated, primarily low-risk women. In order to identify accurately women at high fracture risk, it would be advisable to determine the BMD in women with moderate to high risk of FRAX without BMD.

On challenges in clinical assessment of hip fracture risk using image-based biomechanical modelling: a critical review

INTRODUCTION

Hip fracture is a common health risk among elderly people, due to the prevalence of osteoporosis and accidental fall in the population. Accurate assessment of fracture risk is a crucial step for clinicians to consider patient-by-patient optimal treatments for effective prevention of fractures. Image-based biomechanical modeling has shown promising progress in assessment of fracture risk, and there is still a great possibility for improvement. The purpose of this paper is to identify key issues that need be addressed to improve image-based biomechanical modeling.

MATERIALS AND METHODS

We critically examined issues in consideration and determination of the four biomechanical variables, i.e., risk of fall, fall-induced impact force, bone geometry and bone material quality, which are essential for prediction of hip fracture risk. We closely inspected: limitations introduced by assumptions that are adopted in existing models; deficiencies in methods for construction of biomechanical models, especially for determination of bone material properties from bone images; problems caused by separate use of the variables in clinical study of hip fracture risk; availability of clinical information that are required for validation of biomechanical models.

RESULTS AND CONCLUSIONS

A number of critical issues and gaps were identified. Strategies for effectively addressing the issues were discussed.

Hospitalization in High Fracture Risk Older Adults with Osteoporosis Using the Safe Functional Motion Test: A Longitudinal Analysis

The Safe Functional Motion Test (SFM-5) is a five item performance based clinical assessment tool quantifying habitual daily movement that may increase the risk of osteoporosis and fractures. Fractures are a major cause of hospitalization and contributor to increased health care utilization costs. A sample of 1,700 adults, aged 40 and older, from an osteoporosis specialty clinic were evaluated to determine if the initial SFM-5 score had predictive utility for determining inpatient hospitalization at 12, 24, and 36 months post fracture. When adjusted for sex, age, and prior hospitalization, logistic regression analyses indicated that the SFM-5 score significantly predicted inpatient hospitalization within 12 months, 24 months, and 36 months. For every 10 point decrease in the SFM-5 score, the 1 year risk of hospitalization increased by 24%. The SFM-5 is a tool to use when assessing habitual functional movements and hospitalization risk among high-fracture risk adults.

Development of a model for identification of individuals with high risk of osteoporosis

Many developing countries, including Vietnam, lack DXA resources for the diagnosis of osteoporosis, which poses difficulties in the treatment and prevention of osteoporosis at the individual level. We have developed and validated a prediction model for individualized assessment of osteoporosis based on age and body weight for men and women.

PURPOSE

To estimate the prevalence of osteoporosis and to develop and validate a prediction model for estimating the absolute risk of osteoporosis in the Vietnamese population.

METHODS

The study involved 1477 women and 669 men aged 50 years and older, who were recruited from the general population in Ho Chi Minh City (Vietnam). Bone mineral density (BMD) at the femoral neck, total hip, and lumbar spine was measured by DXA (Hologic Horizon). The diagnosis of osteoporosis was based on BMD T-score (T-score ≤ - 2.5) at the femoral neck or lumbar spine which was derived from a published reference range for the Vietnamese population. The logistic regression model was used to develop the prediction model for men and women separately. The bootstrap method was used to evaluate the model performance using 3 indices: the area under the receiver's operating characteristic curve (AUC), Brier score, and R-squared values.

RESULTS

The prevalence of osteoporosis at any site was 28.3% in women and 15.5% in men. The best predictors of osteoporosis risk were age and body weight. Using these indices, a cut-off of 0.195 for women yielded an AUC of 0.825, Brier score = 0.112, and it explained 33.8% of total variance in risk of osteoporosis between individuals. Similarly, in men, the internal validation with a cut-off of 0.09 yielded good accuracy, with AUC = 0.858, Brier score = 0.040, and R-squared = 30.3%.

CONCLUSION

We have developed and validated a prediction model for individualized assessment of osteoporosis. In settings without DXA, this model can serve as a useful screening tool to identify high-risk individuals for DXA scan.

The Belgian Bone Club 2020 guidelines for the management of osteoporosis in postmenopausal women

PURPOSE

To provide updated evidence-based guidelines for the management of osteoporosis in postmenopausal women in Belgium.

METHODS

The Belgian Bone Club (BBC) gathered a guideline developer group. Nine "Population, Intervention, Comparator, Outcome" (PICO) questions covering screening, diagnosis, non-pharmacological and pharmacological treatments, and monitoring were formulated. A systematic search of MEDLINE, the Cochrane Database of Systematic Reviews, and Scopus was performed to find network meta-analyses, meta-analyses, systematic reviews, guidelines, and recommendations from scientific societies published in the last 10 years. Manual searches were also performed. Summaries of evidence were provided, and recommendations were further validated by the BBC board members and other national scientific societies' experts.

RESULTS

Of the 3840 references in the search, 333 full texts were assessed for eligibility, and 129 met the inclusion criteria. Osteoporosis screening using clinical risk factors should be considered. Patients with a recent (<2 years) major osteoporotic fracture were considered at very high and imminent risk of future fracture. The combination of bone mineral density measured by dual-energy X-ray absorptiometry and 10-year fracture risk was used to categorize patients as low or high risk. Patient education, the combination of weight-bearing and resistance training, and optimal calcium intake and vitamin D status were recommended. Antiresorptive and anabolic osteoporosis treatment should be considered for patients at high and very high fracture risk, respectively. Follow-up should focus on compliance, and patient-tailored monitoring should be considered.

CONCLUSION

BBC guidelines and 25 guideline recommendations bridge the gap between research and clinical practice for the screening, diagnosis, and management of osteoporosis.

COPD as an independent risk factor for osteoporosis and fractures

Fractures are common in individuals with COPD and occur at higher bone mass values than expected. COPD appears to be an important risk factor for bone fragility.

INTRODUCTION

Patients with chronic obstructive pulmonary disease (COPD) have an increased risk of osteoporosis and fractures, but screening and prophylactic measures to prevent both disorders are often neglected in this population. This case-control study assessed the prevalence of osteopenia, osteoporosis, and fractures in patients with COPD, and identified potential risk factors for fractures in this population.

METHODS

Overall, 91 patients with COPD (COPD group; COPDG) and 81 age- and sex-matched controls (control group; CG) were assessed with bone mineral density (BMD), thoracic/lumbar spine radiographs, and serum PTH and 25-hydroxyvitamin D (25[OH]D) levels. The occurrence of prior fractures was retrieved from clinical history.

RESULTS

The prevalence of total fractures in the COPDG was 57.1% (odds of fracture 4.7 times greater compared with the CG), and the femoral neck T-score emerged as the best predictor of fractures. Compared with the CG, the COPDG had lower spine and femoral BMD (p ≤ 0.01) and 25(OH)D levels (p = 0.01) and 2.6 times greater odds of osteoporosis. Among men, vertebral fractures were more prevalent in the COPDG versus CG (25.9% vs. 6.5%, respectively, p = 0.01). The odds of fracture increased with femoral neck T-scores ≤ - 2.7 in the CG and ≤ - 0.6 in the COPDG.

CONCLUSION

These results add robust evidence to an increased odds of osteoporosis and fractures in COPD. Fractures in the COPDG occurred at higher BMD values than expected, suggesting that COPD may be an independent marker of fracture risk, reinforcing a need for regular osteoporosis screening with BMD measurement and prophylaxis of fractures in patients with this disorder.

Controversies Surrounding the BMD Reporting Standard for the Determination of 10-Year Absolute Fracture Risk: A Canadian Perspective

The Canadian Association of Radiologists and Osteoporosis Canada currently endorse a fracture risk prediction tool called CAROC. It has been used in Canada since 2005 with an update in 2010. It is an integral part of bone mineral densitometry reporting across the country. New osteoporosis guidelines from Osteoporosis Canada (OC) are expected in the near future. There has been pressure on radiologists to report fracture risk using an alternative fracture risk prediction platform called FRAX. In addition, OC collaborated in the development of the Canadian FRAX model and has been copromoting both FRAX and CAROC, raising the prospect that new guidelines may seek to replace CAROC with FRAX for fracture risk determination. A number of concerns have been raised about FRAX, including: (1) FRAX has not released its algorithms to the public domain with the consequence that it is impossible to verify results for an individual patient; (2) FRAX has incorrectly claimed that it was developed by the World Health Organization (WHO) and has used this affiliation to promote itself until recently ordered by the WHO to desist; (3) FRAX requires collection of additional clinical information beyond that needed for CAROC, and this patient-reported medical data is prone to substantial error; and (4) despite claims to the contrary, there are no valid studies comparing FRAX to CAROC. We believe it is important that radiologists be aware of these issues in order to provide input into future Technical Standards for Bone Mineral Densitometry Reporting of the Canadian Association of Radiologists.

Cost-Effectiveness of the Screening for the Primary Prevention of Fragility Hip Fracture in Spain Using FRAX®

To assess the cost-effectiveness of the primary prevention of fragility hip fractures through opportunistic risk-based screening using FRAX^® among women aged 70 to 89 years, and the subsequent treatment with alendronate in women at high-risk, from the Spanish national health system perspective. We performed a discrete-event simulation model. Women were categorized in low, intermediate and high-risk of fragility hip fracture through screening based on the FRAX^® risk assessment tool score (Spanish version). Low-risk women received lifestyle recommendations whereas the high-risk group was assigned to alendronate treatment. For women at intermediate-risk, treatment decision was based on a recalculated score considering bone mineral density (BMD). The cost-effectiveness analysis tested six scenarios defined by different FRAX^® cut-off values assessing the incremental costs per averted fracture in 20 years. Deterministic sensitivity analysis was performed. We included a random sample of 5146 women obtained from a Spanish cohort of women referred for BMD. The most cost-effective intervention had an Incremental Cost-effectiveness Ratio (ICER) of 57,390 € per averted hip fracture and consisted of using the FRAX^® score without BMD and treating women with a score higher than 5%. The ICER exceeded the acceptability threshold of 25,000 € in all the scenarios. Sensitivity analysis based on time to fracture, treatment efficacy, adherence to treatment and cost of dependence resulted in ICERs ranging from 39,216 € to 254,400 €. An ICER of 24,970 € was obtained when alendronate cost was reduced to 1.13 € per month. The use of FRAX^® as screening tool followed by alendronate treatment is not cost-effective in senior women in Spain. Other primary preventions strategies are advisable.

Methodological standards for the development and evaluation of clinical prediction rules: a review of the literature

Clinical prediction rules (CPRs) that predict the absolute risk of a clinical condition or future outcome for individual patients are abundant in the medical literature; however, systematic reviews have demonstrated shortcomings in the methodological quality and reporting of prediction studies. To maximise the potential and clinical usefulness of CPRs, they must be rigorously developed and validated, and their impact on clinical practice and patient outcomes must be evaluated. This review aims to present a comprehensive overview of the stages involved in the development, validation and evaluation of CPRs, and to describe in detail the methodological standards required at each stage, illustrated with examples where appropriate. Important features of the study design, statistical analysis, modelling strategy, data collection, performance assessment, CPR presentation and reporting are discussed, in addition to other, often overlooked aspects such as the acceptability, cost-effectiveness and longer-term implementation of CPRs, and their comparison with clinical judgement. Although the development and evaluation of a robust, clinically useful CPR is anything but straightforward, adherence to the plethora of methodological standards, recommendations and frameworks at each stage will assist in the development of a rigorous CPR that has the potential to contribute usefully to clinical practice and decision-making and have a positive impact on patient care.

Homogeneity in prediction of survival probabilities for subcategories of hipprosthesis data: the Nordic Arthroplasty Register Association, 2000-2013

Introduction: The four countries in the Nordic Arthroplasty Register Association (NARA) share geographic proximity, culture, and ethnicity. Pooling data from different sources in order to obtain higher precision and accuracy of survival-probability estimates is appealing. Nevertheless, survival probabilities of hip replacements vary between the countries. As such, risk prediction for individual patients within countries may be problematic if data are merged. In this study, our primary question was to address when data merging for estimating prosthesis survival in subcategories of patients is advantageous for survival prediction of individual patients, and at what sample sizes this may be advised.

Methods: Patients undergoing total hip replacements for osteoarthritis between January 1, 2000 and December 31, 2013 in the four Nordic countries were studied. A total of 184,507 patients were stratified into 360 patient subcategories based on country, age-group, sex, fixation, head size, and articulation. For each patient category, we determined the sample size needed from a single country to obtain a more accurate and precise estimate of prosthesis-survival probability at 5 and 10 years compared to an estimate using data from all countries. The comparison was done using mean-square error.

Results: We found large variations in the sample size needed, ranging from 40 to 2,060 hips, before an estimate from a single Nordic country was more accurate and precise than estimates based on the NARA data.

Conclusion: Using pooled survival-probability estimates for individual risk prediction may be imprecise if there is heterogeneity in the pooled data sources. By applying mean-square error, we demonstrate that for small sample sizes, applying the larger NARA database may provide a more accurate and precise estimate; however, this effect is not consistent and varies with the characteristics of the subcategory.

Numerical modelling of hip fracture patterns in human femur

BACKGROUND AND OBJECTIVE

Hip fracture morphology is an important factor determining the ulterior surgical repair and treatment, because of the dependence of the treatment on fracture morphology. Although numerical modelling can be a valuable tool for fracture prediction, the simulation of femur fracture is not simple due to the complexity of bone architecture and the numerical techniques required for simulation of crack propagation. Numerical models assuming homogeneous fracture mechanical properties commonly fail in the prediction of fracture patterns. This paper focuses on the prediction of femur fracture based on the development of a finite element model able to simulate the generation of long crack paths.

METHODS

The finite element model developed in this work demonstrates the capability of predicting fracture patterns under stance loading configuration, allowing the distinction between the main fracture paths: intracapsular and extracapsular fractures. It is worth noting the prediction of different fracture patterns for the same loading conditions, as observed during experimental tests.

RESULTS AND CONCLUSIONS

The internal distribution of bone mineral density and femur geometry strongly influences the femur fracture morphology and fracture load. Experimental fracture paths have been analysed by means of micro-computed tomography allowing the comparison of predicted and experimental crack surfaces, confirming the good accuracy of the numerical model.

Performance of predictive tools to identify individuals at risk of non-traumatic fracture: a systematic review, meta-analysis, and meta-regression

There is no consensus on which tool is the most accurate to assess fracture risk. The results of this systematic review suggest that QFracture, Fracture Risk Assessment Tool (FRAX) with BMD, and Garvan with BMD are the tools with the best discriminative ability. More studies assessing the comparative performance of current tools are needed.

INTRODUCTION

Many tools exist to assess fracture risk. This review aims to determine which tools have the best predictive accuracy to identify individuals at high risk of non-traumatic fracture.

METHODS

Studies assessing the accuracy of tools for prediction of fracture were searched in MEDLINE, EMBASE, Evidence-Based Medicine Reviews, and Global Health. Studies were eligible if discrimination was assessed in a population independent of the derivation cohort. Meta-analyses and meta-regressions were performed on areas under the ROC curve (AUCs). Gender, mean age, age range, and study quality were used as adjustment variables.

RESULTS

We identified 53 validation studies assessing the discriminative ability of 14 tools. Given the small number of studies on some tools, only FRAX, Garvan, and QFracture were compared using meta-regression models. In the unadjusted analyses, QFracture had the best discriminative ability to predict hip fracture (AUC = 0.88). In the adjusted analysis, FRAX with BMD (AUC = 0.81) and Garvan with BMD (AUC = 0.79) had the highest AUCs. For prediction of major osteoporotic fracture, QFracture had the best discriminative ability (AUC = 0.77). For prediction of osteoporotic or any fracture, FRAX with BMD and Garvan with BMD had higher discriminative ability than their versions without BMD (FRAX: AUC = 0.72 vs 0.69, Garvan: AUC = 0.72 vs 0.65). A significant amount of heterogeneity was present in the analyses.

CONCLUSIONS

QFracture, FRAX with BMD, and Garvan with BMD have the highest discriminative performance for predicting fracture. Additional studies in which the performance of current tools is assessed in the same individuals may be performed to confirm this conclusion.

Usefulness of the Trabecular Bone Score for assessing the risk of osteoporotic fracture

INTRODUCTION AND OBJECTIVES

The trabecular bone score (TBS) is an imaging technique that assesses the condition of the trabecular microarchitecture. Preliminary results suggest that TBS, along with the bone mineral density assessment, could improve the calculation of the osteoporotic fracture risk. The aim of this study was to analyse TBS values and their relationship with the clinical characteristics, bone mineral density and history of fractures of a cohort of posmenopausal women.

MATERIAL AND METHODS

We analysed 2,257 posmenopausal women from the FRODOS cohort, which was created to determine the risk factors for osteoporotic fracture through a clinical survey and bone densitometry with vertebral morphometry. TBS was applied to the densitometry images. TBS values ≤1230 were considered indicative of degraded microarchitecture. We performed a simple and multiple linear regression to determine the factors associated with this index.

RESULTS

The mean TBS value in L1-L4 was 1.203±0.121. Some 55.3% of the women showed values indicating degraded microarchitecture. In the multiple linear regression analysis, the factors associated with low TBS values were age, weight, height, spinal T-score, glucocorticoid treatment, presence of type 2 diabetes and a history of fractures due to frailty.

CONCLUSIONS

TBS showed microarchitecture degradation values in the participants of the FRODOS cohort and was associated with anthropometric factors, low bone mineral density values, the presence of fractures, a history of type 2 diabetes mellitus and the use of glucocorticoids.

Fracture Risk Assessment With FRAX Using Real-World Data in a Population-Based Cohort From Israel

The predictive value of the World Health Organization's Fracture Risk Assessment Tool (FRAX) was evaluated using real-world community data. A population-based cohort of 141,320 women aged 50-90 years (median age, 58 years; interquartile range, 54-67) in 2004 was extracted from the central database of a large Israeli health-care services provider and insurer. Retrospective FRAX scores were calculated using computerized health records and compared with actual incidence of major osteoporotic fractures (MOFs) during the following 10 years. Fracture proportions of 6.9% for MOFs and 2.2% for hip fractures were expected, as opposed to 13.5% and 2.9% observed. The area under the receiver operating characteristic curve (AUC) of FRAX scores calculated without the inclusion of bone mineral density (BMD) data was 0.65 (95% confidence interval: 0.65, 0.66) for MOF and 0.82 (95% confidence interval: 0.81, 0.82) for hip fracture. A total of 16,578 subjects had BMD data at the index date, and their risk estimates based solely on BMD exhibited lower predictive performance for both MOFs (AUC = 0.62 vs. 0.65; P = 0.003) and hip fractures (AUC = 0.78 vs. 0.84; P < 0.001) as compared with FRAX. FRAX scores based on electronic health records provided reasonable discrimination despite some underestimation of the absolute risk of nonhip fractures. Integration of FRAX with routine clinical systems could increase implementation in daily practice and improve risk detection, especially for patients without BMD data.

Comparing self-perceived and estimated fracture risk by FRAX® of women with osteoporosis

In this study, we compared subjective fracture risks of Hungarian women with osteoporosis to FRAX®-based estimates. Patients with a previous fracture, parental hip fracture, low femoral T-score, higher age, and higher BMI were more likely to underestimate their risks. Patients also failed to associate risk factors with an increased risk of fractures.

PURPOSE

The main objectives were to explore associations between self-perceived 10-year fracture risks of women with osteoporosis (OP) and their risks calculated by the FRAX® algorithm and to identify determinants of the underestimation of risk.

METHODS

We carried out a cross-sectional study in 11 OP centers in Hungary and collected data on the risk factors considered by the FRAX® calculator. Patients estimated their subjective 10-year probability of any major osteoporotic and hip fracture numerically, in percentages and also on a visual analog scale (VAS). We compared subjective and FRAX® estimates and applied logistic regression to analyze the determinants of the underestimation of risk. Associations between risk factors and subjective risk were explored using linear probability models.

RESULTS

Nine hundred seventy-two OP patients were included in the analysis. Major OP and hip fracture risk by FRAX® were on average 20.1 and 10.5%, while subjective estimates were significantly higher, 30.0 and 24.7%, respectively. Correlations between FRAX® and subjective measures were very weak (r = 0.12-0.16). Underestimation of major OP fracture risk was associated with having had a single previous fracture (OR = 2.0), parental hip fracture (OR = 3.4), femoral T-score ≤-2.5 (OR = 4.2), higher age, body mass index, and better general health state. We did not find significant associations between subjective risk estimates and most of the risk factors except for previous fractures.

CONCLUSIONS

Hungarian OP patients fail to recognize most of the risk factors of fractures. Thus, education of patients about these risk factors would be beneficial especially for the elderly with a low femoral T-score and parental hip fracture history.

Diversity in fall characteristics hampers effective prevention: the precipitants, the environment, the fall and the injury

Falls among the elderly are common and characteristics may differ between injurious and non-injurious falls. Among 887 older Australian women followed for 1.6 years, 32% fell annually. Only 8.5% resulted in fracture and/or hospital admission. The characteristics of those falls are indistinguishable from those not coming to medical attention.

INTRODUCTION

The precipitants and environment of all falls occurring among a large cohort of older Caucasian women were categorised by injury status to determine if the characteristics differed between injurious and non-injurious falls.

METHODS

Among 887 Australian women (70+ years), falls were ascertained using monthly postcard calendars and a questionnaire was administered for each fall. Hospital admissions and fractures were independently confirmed.

RESULTS

All falls were reported for a mean observation time of 577 (IQR 546-607) days per participant, equating to a total 1400 person-years. Thirty-two percent fell at least once per year. The most common features of a fall were that the faller was walking (61%) at home (61%) during the day (88%) and lost balance (32%). Only 12% of all falls occurred at night. Despite no difference in the type of injury between day and night, the likelihood of being hospitalised from a fall at night was 4.5 times greater than that of a daytime fall with adjustment for injury type and participant age (OR 4.5, 95% CI 2.1, 9.5; p < 0.001). Of all falls, approximately one third were associated with no injury to the faller (31%), one third reported a single injury (37%) and one third reported more than one injury (32%). In 95% of falls, the faller was not admitted to hospital. Only 5% of falls resulted in fracture(s).

CONCLUSIONS

Our findings demonstrate the significant diversity of precipitants and environment where falls commonly occur among older community-dwelling women. Falls resulting in fracture and/or hospital admission collectively represent 8.5% of all falls and their characteristics are indistinguishable from falls not coming to medical attention and incurring no apparent cost to the health system.

Do we need bone mineral density to estimate osteoporotic fracture risk? A 10-year prospective multicentre validation study

Objective

Evaluate the performance of FRAX®, with and without bone mineral densitometry (BMD), in predicting the occurrence of fragility fractures over 10 years.

Methods

Participants aged ≥40 years at baseline, with a complete set of data and a minimum of 8.5 years of follow-up were identified from three cohorts (n=2626). Ten-year fracture risk at baseline were estimated with FRAX® and assessed by comparison with observed fractures and receiver operating characteristic analysis.

Results

During a mean (SD) follow-up of 9.12 (1.5) years, 178 participants suffered a major osteoporotic (MOP) fracture and 28 sustained a hip fracture. The predictive performance of FRAX® was superior to that of BMD alone for both MOP and hip fractures. The area under the curve (AUC) of FRAX® without BMD was 0.76 (95% CI 0.72 to 0.79) for MOP fractures and 0.78 (95% CI 0.69 to 0.86) for hip fractures. No significant improvements were found when BMD was added to clinical variables to predict either MOP (0.78, 95% CI 0.74 to 0.82, p=0.25) or hip fractures (0.79, 95% CI 0.69 to 0.89, p=0.72).

AUCs for FRAX® (with and without BMD) were greater for men than for women. FRAX®, with and without BMD, tended to underestimate the number of MOP fractures and to overestimate the number of hip fractures in females. In men, the number of observed fractures were within the 95% CI of the number predicted, both with and without BMD.

Conclusion

FRAX® without BMD provided good fracture prediction. Adding BMD to FRAX® did not improve the performance of the tool in the general population.

Fracture Risk Assessment in Clinical Practice: Why Do It? What to Do It With?

Fracture is the outcome of concern in osteoporosis, and fracture reduction is the primary goal of osteoporosis treatment. Fracture risk assessment is a critical component in osteoporosis management. The earlier approach of deciding on whether to treat solely based on bone mineral density (BMD) T-scores has been supplanted by employing the concept of absolute risk over medium time periods and more encompassing integration of clinical risk factors with or without BMD into robust fracture risk assessment tools. Fracture risk estimation allows for identifying high-risk patient groups not only at a health system and population-based level and thereby allowing allocation of financial resources to the people most at risk, but also at an individual level for the clinician to involve the patient in shared decision-making processes for treatment. The process of fracture risk assessment involves several steps including performing a thorough history and physical examination, assessing BMD, doing radiological assessment for vertebral fractures, and laboratory evaluation to rule out secondary contributors to osteoporosis. The data thus obtained can be input into any one of several fracture risk assessment tools that are now available. The decision on which tool to use can be made on the background of country-specific guidelines, although it is imperative that the physician be aware of the limitations inherent to whichever tool is chosen. This article aims to provide a brief overview of why fracture risk estimation is important and the methods that can be employed for it by the physician in clinical practice.

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.

External validation and comparison of three prediction tools for risk of osteoporotic fractures using data from population based electronic health records: retrospective cohort study

OBJECTIVE

 To directly compare the performance and externally validate the three most studied prediction tools for osteoporotic fractures-QFracture, FRAX, and Garvan-using data from electronic health records.

DESIGN

 Retrospective cohort study.

SETTING

 Payer provider healthcare organisation in Israel.

PARTICIPANTS

 1 054 815 members aged 50 to 90 years for comparison between tools and cohorts of different age ranges, corresponding to those in each tools' development study, for tool specific external validation.

MAIN OUTCOME MEASURE

 First diagnosis of a major osteoporotic fracture (for QFracture and FRAX tools) and hip fractures (for all three tools) recorded in electronic health records from 2010 to 2014. Observed fracture rates were compared to probabilities predicted retrospectively as of 2010.

RESULTS

 The observed five year hip fracture rate was 2.7% and the rate for major osteoporotic fractures was 7.7%. The areas under the receiver operating curve (AUC) for hip fracture prediction were 82.7% for QFracture, 81.5% for FRAX, and 77.8% for Garvan. For major osteoporotic fractures, AUCs were 71.2% for QFracture and 71.4% for FRAX. All the tools underestimated the fracture risk, but the average observed to predicted ratios and the calibration slopes of FRAX were closest to 1. Tool specific validation analyses yielded hip fracture prediction AUCs of 88.0% for QFracture (among those aged 30-100 years), 81.5% for FRAX (50-90 years), and 71.2% for Garvan (60-95 years).

CONCLUSIONS

 Both QFracture and FRAX had high discriminatory power for hip fracture prediction, with QFracture performing slightly better. This performance gap was more pronounced in previous studies, likely because of broader age inclusion criteria for QFracture validations. The simpler FRAX performed almost as well as QFracture for hip fracture prediction, and may have advantages if some of the input data required for QFracture are not available. However, both tools require calibration before implementation.

Serum miRNA Signatures Are Indicative of Skeletal Fractures in Postmenopausal Women With and Without Type 2 Diabetes and Influence Osteogenic and Adipogenic Differentiation of Adipose Tissue-Derived Mesenchymal Stem Cells In Vitro

Standard DXA measurements, including Fracture Risk Assessment Tool (FRAX) scores, have shown limitations in assessing fracture risk in Type 2 Diabetes (T2D), underscoring the need for novel biomarkers and suggesting that other pathomechanisms may drive diabetic bone fragility. MicroRNAs (miRNAs) are secreted into the circulation from cells of various tissues proportional to local disease severity and were recently found to be crucial to bone homeostasis and T2D. Here, we studied, if and which circulating miRNAs or combinations of miRNAs can discriminate best fracture status in a well-characterized study of diabetic bone disease and postmenopausal osteoporosis (n = 80 postmenopausal women). We then tested the most discriminative and most frequent miRNAs in vitro. Using miRNA-qPCR-arrays, we showed that 48 miRNAs can differentiate fracture status in T2D women and that several combinations of four miRNAs can discriminate diabetes-related fractures with high specificity and sensitivity (area under the receiver-operating characteristic curve values [AUCs], 0.92 to 0.96; 95% CI, 0.88 to 0.98). For the osteoporotic study arm, 23 miRNAs were fracture-indicative and potential combinations of four miRNAs showed AUCs from 0.97 to 1.00 (95% CI, 0.93 to 1.00). Because a role in bone homeostasis for those miRNAs that were most discriminative and most present among all miRNA combinations had not been described, we performed in vitro functional studies in human adipose tissue-derived mesenchymal stem cells to investigate the effect of miR-550a-5p, miR-188-3p, and miR-382-3p on osteogenesis, adipogenesis, and cell proliferation. We found that miR-382-3p significantly enhanced osteogenic differentiation (p < 0.001), whereas miR-550a-5p inhibited this process (p < 0.001). Both miRNAs, miR-382-3p and miR-550a-5p, impaired adipogenic differentiation, whereas miR-188-3p did not exert an effect on adipogenesis. None of the miRNAs affected significantly cell proliferation. Our data suggest for the first time that miRNAs are linked to fragility fractures in T2D postmenopausal women and should be further investigated for their diagnostic potential and their detailed function in diabetic bone. © 2016 American Society for Bone and Mineral Research.

How Good is Our Best Guess? Clinical Application of the WHO FRAX Tool in Osteoporotic Fracture Risk Determination and Treatment Decisions

Historically, treatment decisions for osteoporosis were based on bone mineral density. However, many fractures occur in patients with T-scores outside the osteoporotic range, emphasizing the importance of multi-factorial risk assessments. The World Health Organization Fracture Risk Assessment Tool (FRAX) predicts 10-year risk of osteoporotic fracture. We hypothesized that physicians' clinical estimates of osteoporotic fracture risk would differ significantly from that calculated by FRAX. Thus, treatment decisions would differ depending whether or not physicians used FRAX. A survey consisting of five clinical scenarios was administered to 76 endocrinologists, family physicians, internists, and internal medicine residents. They were asked to estimate the osteoporotic fracture risk and decide whether they would offer preventative treatment. Their estimates were compared to the risk predicted by FRAX and national treatment threshold guidelines. The primary outcome was the difference between the participant's estimate and the FRAX-based estimate of the 10-year risk of osteoporotic fracture for each scenario. In each scenario, physicians statistically significantly over-estimated fracture risk compared to that predicted by FRAX. Estimates for hip fracture risk were 2-4 times higher than FRAX estimates. The major osteoporotic fracture risk at which participants would offer treatment varied with physician group, with endocrinologists, family physicians, and residents requiring a 10-20 % 10-year risk, while internal medicine physician thresholds ranged from 2 to 20 %. Physicians greatly over-estimated the risk of hip fracture based on clinical information. FRAX is necessary to accurately quantify risk, but because physicians varied in the level of risk required before they would offer treatment, uniform approaches to risk estimation may still not result in uniform clinical treatment decisions.

Development of a Korean Fracture Risk Score (KFRS) for Predicting Osteoporotic Fracture Risk: Analysis of Data from the Korean National Health Insurance Service

Background

Asian-specific prediction models for estimating individual risk of osteoporotic fractures are rare. We developed a Korean fracture risk prediction model using clinical risk factors and assessed validity of the final model.

Methods

A total of 718,306 Korean men and women aged 50–90 years were followed for 7 years in a national system-based cohort study. In total, 50% of the subjects were assigned randomly to the development dataset and 50% were assigned to the validation dataset. Clinical risk factors for osteoporotic fracture were assessed at the biennial health check. Data on osteoporotic fractures during the follow-up period were identified by ICD-10 codes and the nationwide database of the National Health Insurance Service (NHIS).

Results

During the follow-up period, 19,840 osteoporotic fractures were reported (4,889 in men and 14,951 in women) in the development dataset. The assessment tool called the Korean Fracture Risk Score (KFRS) is comprised of a set of nine variables, including age, body mass index, recent fragility fracture, current smoking, high alcohol intake, lack of regular exercise, recent use of oral glucocorticoid, rheumatoid arthritis, and other causes of secondary osteoporosis. The KFRS predicted osteoporotic fractures over the 7 years. This score was validated using an independent dataset. A close relationship with overall fracture rate was observed when we compared the mean predicted scores after applying the KFRS with the observed risks after 7 years within each 10th of predicted risk.

Conclusion

We developed a Korean specific prediction model for osteoporotic fractures. The KFRS was able to predict risk of fracture in the primary population without bone mineral density testing and is therefore suitable for use in both clinical setting and self-assessment. The website is available at http://www.nhis.or.kr.

Analysis of fracture healing in osteopenic bone caused by disuse: experimental study

Osteoporosis has become a serious global public health issue. Hence, osteoporotic fracture healing has been investigated in several previous studies because there is still controversy over the effect osteoporosis has on the healing process. The current study aimed to analyze two different periods of bone healing in normal and osteopenic rats. Sixty, 7-week-old female Wistar rats were randomly divided into four groups: unrestricted and immobilized for 2 weeks after osteotomy (OU2), suspended and immobilized for 2 weeks after osteotomy (OS2), unrestricted and immobilized for 6 weeks after osteotomy (OU6), and suspended and immobilized for 6 weeks after osteotomy (OS6). Osteotomy was performed in the middle third of the right tibia 21 days after tail suspension, when the osteopenic condition was already set. The fractured limb was then immobilized by orthosis. Tibias were collected 2 and 6 weeks after osteotomy, and were analyzed by bone densitometry, mechanical testing, and histomorphometry. Bone mineral density values from bony calluses were significantly lower in the 2-week post-osteotomy groups compared with the 6-week post-osteotomy groups (multivariate general linear model analysis, P<0.000). Similarly, the mechanical properties showed that animals had stronger bones 6 weeks after osteotomy compared with 2 weeks after osteotomy (multivariate general linear model analysis, P<0.000). Histomorphometry indicated gradual bone healing. Results showed that osteopenia did not influence the bone healing process, and that time was an independent determinant factor regardless of whether the fracture was osteopenic. This suggests that the body is able to compensate for the negative effects of suspension.

The accuracy of osteoporotic fracture risk prediction tools: a systematic review and meta-analysis

OBJECTIVES

To identify and synthesise the best available evidence on the accuracy of the currently available tools for predicting fracture risk.

METHODS

We systematically searched PubMed MEDLINE, Embase and Cochrane databases to 2014. Two reviewers independently selected articles, collected data from studies, and carried out a hand search of the references of the included studies. The Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS) checklist was used, and the primary outcome was the area under the curve (AUC) and 95% CIs, obtained from receiver operating characteristic (ROC) analyses. We excluded tools if they had not been externally validated or were designed for specific disease populations. Random effects meta-analyses were performed with the selected tools.

RESULTS

Forty-five studies met inclusion criteria, corresponding to 13 different tools. Only three tools had been tested more than once in a population-based setting: FRAX (26 studies in 9 countries), GARVAN (6 studies in 3 countries) and QFracture (3 studies in the UK, 1 also including Irish participants). Twenty studies with these three tools were included in a total of 17 meta-analyses (for hip or major osteoporotic fractures; men or women; with or without bone mineral density).

CONCLUSIONS

Most of the 13 tools are feasible in clinical practice. FRAX has the largest number of externally validated and independent studies. The overall accuracy of the different tools is satisfactory (>0.70), with QFracture reaching 0.89 (95% CI 0.88 to 0.89). Significant methodological limitations were observed in many studies, suggesting caution when comparing tools based solely on the AUC.

Systematic review and meta-analysis of the performance of clinical risk assessment instruments for screening for osteoporosis or low bone density

We performed a systematic review and meta-analysis of the performance of clinical risk assessment instruments for screening for DXA-determined osteoporosis or low bone density. Commonly evaluated risk instruments showed high sensitivity approaching or exceeding 90% at particular thresholds within various populations but low specificity at thresholds required for high sensitivity. Simpler instruments, such as OST, generally performed as well as or better than more complex instruments.

INTRODUCTION

The purpose of the study is to systematically review the performance of clinical risk assessment instruments for screening for dual-energy X-ray absorptiometry (DXA)-determined osteoporosis or low bone density.

METHODS

Systematic review and meta-analysis were performed. Multiple literature sources were searched, and data extracted and analyzed from included references.

RESULTS

One hundred eight references met inclusion criteria. Studies assessed many instruments in 34 countries, most commonly the Osteoporosis Self-Assessment Tool (OST), the Simple Calculated Osteoporosis Risk Estimation (SCORE) instrument, the Osteoporosis Self-Assessment Tool for Asians (OSTA), the Osteoporosis Risk Assessment Instrument (ORAI), and body weight criteria. Meta-analyses of studies evaluating OST using a cutoff threshold of <1 to identify US postmenopausal women with osteoporosis at the femoral neck provided summary sensitivity and specificity estimates of 89% (95%CI 82-96%) and 41% (95%CI 23-59%), respectively. Meta-analyses of studies evaluating OST using a cutoff threshold of 3 to identify US men with osteoporosis at the femoral neck, total hip, or lumbar spine provided summary sensitivity and specificity estimates of 88% (95%CI 79-97%) and 55% (95%CI 42-68%), respectively. Frequently evaluated instruments each had thresholds and populations for which sensitivity for osteoporosis or low bone mass detection approached or exceeded 90% but always with a trade-off of relatively low specificity.

CONCLUSIONS

Commonly evaluated clinical risk assessment instruments each showed high sensitivity approaching or exceeding 90% for identifying individuals with DXA-determined osteoporosis or low BMD at certain thresholds in different populations but low specificity at thresholds required for high sensitivity. Simpler instruments, such as OST, generally performed as well as or better than more complex instruments.

Fragility fracture: recent developments in risk assessment

More than half of older women who sustain a fragility fracture do not have osteoporosis by World Health Organization (WHO) bone mineral density (BMD) criteria; and, while BMD has been used to assess fracture risk for over 30 years, a range of other skeletal and nonskeletal clinical risk factors (CRFs) for fracture have been recognized. More than 30 assessment tools using CRFs have been developed, some predicting fracture risk and others low BMD alone. Recent systematic reviews have reported that many tools have not been validated against fracture incidence, and that the complexity of tools and the number of CRFs included do not ensure best performance with poor assessment of (internal or comparative) validity. Internationally, FRAX® is the most commonly recommended tool, in addition to QFracture in the UK, The Canadian Association of Radiologists and Osteoporosis Canada (CAROC) tool in Canada and Garvan in Australia. All tools estimate standard 10-year risk of major osteoporotic and 10-year risk of hip fracture: FRAX® is able to estimate fracture risk either with or without BMD, but CAROC and Garvan both require BMD and QFracture does not. The best evidence for the utility of these tools is in case finding but there may be future prospects for the use of 10-year fracture risk as a common currency with reference to the benefits of treatment, whether pharmacological or lifestyle. The use of this metric is important in supporting health economic analyses. However, further calibration studies will be needed to prove that the tools are robust and that their estimates can be used in supporting treatment decisions, independent of BMD.

Comparison of fracture risk prediction by the US Preventive Services Task Force strategy and two alternative strategies in women 50-64 years old in the Women's Health Initiative

CONTEXT

The United States Preventive Services Task Force (USPSTF) recommends osteoporosis screening for women younger than 65 years whose 10-year predicted risk of major osteoporotic fracture (MOF) is at least 9.3% using the Fracture Risk Assessment Tool. In postmenopausal women age 50-64 years old, it is uncertain how the USPSTF screening strategy compares with the Osteoporosis Self-Assessment Tool and the Simple Calculated Osteoporosis Risk Estimate (SCORE) in discriminating women who will and will not experience MOF.

OBJECTIVE

This study aimed to assess the sensitivity, specificity, and area under the receiver operating characteristic curve of the three strategies for discrimination of incident MOF over 10 years of follow-up among postmenopausal women age 50-64 years.

SETTING AND DESIGN

This was a prospective study conducted between 1993-2008 at 40 US Centers.

PARTICIPANTS

We analyzed data from participants of the Women's Health Initiative Observational Study and Clinical Trials, age 50-64 years, not taking osteoporosis medication (n = 62 492).

MAIN OUTCOME MEASURES

The main outcome was 10-year (observed) incidence of MOF.

RESULTS

For identifying women with incident MOF, sensitivity of the strategies ranged from 25.8-39.8%, specificity ranged from 60.7-65.8%, and AUC values ranged from 0.52-0.56. The sensitivity of the USPSTF strategy for identifying incident MOF ranged from 4.7% (3.3-6.0) among women age 50-54 years to 37.3% (35.4-39.1) for women age 60-64 years. Adjusting the thresholds to improve sensitivity resulted in decreased specificity.

CONCLUSIONS

Our findings do not support use of the USPSTF strategy, Osteoporosis Self-Assessment Tool, or SCORE to identify younger postmenopausal women who are at higher risk of fracture. Our findings suggest that fracture prediction in younger postmenopausal women requires assessment of risk factors not included in currently available strategies.

External validation of the Garvan nomograms for predicting absolute fracture risk: the Tromsø study

Background

Absolute risk estimation is a preferred approach for assessing fracture risk and treatment decision making. This study aimed to evaluate and validate the predictive performance of the Garvan Fracture Risk Calculator in a Norwegian cohort.

Methods

The analysis included 1637 women and 1355 aged 60+ years from the Tromsø study. All incident fragility fractures between 2001 and 2009 were registered. The predicted probabilities of non-vertebral osteoporotic and hip fractures were determined using models with and without BMD. The discrimination and calibration of the models were assessed. Reclassification analysis was used to compare the models performance.

Results

The incidence of osteoporotic and hip fracture was 31.5 and 8.6 per 1000 population in women, respectively; in men the corresponding incidence was 12.2 and 5.1. The predicted 5-year and 10-year probability of fractures was consistently higher in the fracture group than the non-fracture group for all models. The 10-year predicted probabilities of hip fracture in those with fracture was 2.8 (women) to 3.1 times (men) higher than those without fracture. There was a close agreement between predicted and observed risk in both sexes and up to the fifth quintile. Among those in the highest quintile of risk, the models over-estimated the risk of fracture. Models with BMD performed better than models with body weight in correct classification of risk in individuals with and without fracture. The overall net decrease in reclassification of the model with weight compared to the model with BMD was 10.6% (p = 0.008) in women and 17.2% (p = 0.001) in men for osteoporotic fractures, and 13.3% (p = 0.07) in women and 17.5% (p = 0.09) in men for hip fracture.

Conclusions

The Garvan Fracture Risk Calculator is valid and clinically useful in identifying individuals at high risk of fracture. The models with BMD performed better than those with body weight in fracture risk prediction.

Novel assessment tools for osteoporosis diagnosis and treatment

This review describes new technologies for the diagnosis and treatment, including fracture risk prediction, of postmenopausal osteoporosis. Four promising technologies and their potential for clinical translation and basic science studies are discussed. These include reference point indentation (RPI), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and magnetic resonance imaging (MRI). While each modality exploits different physical principles, the commonality is that none of them require use of ionizing radiation. To provide context for the new developments, brief summaries are provided for the current state of biomarker assays, fracture risk assessment (FRAX), and other fracture risk prediction algorithms and quantitative ultrasound (QUS) measurements.