Fracture prediction from FRAX for Canadian ethnic groups: a registry-based cohort study

Revision of the 1994 World Health Organization T-score definition of osteoporosis for use in older East Asian women and men to reconcile it with their lifetime risk of fragility fracture

The 1994 WHO criterion of a T-score ≤ -2.5 for densitometric osteoporosis was chosen because it results in a prevalence commensurate with the observed lifetime risk of fragility fractures in Caucasian women aged ≥ 50 years. Due to the much lower risk of fragility fracture among East Asians, the application of the conventional WHO criterion to East Asians leads to an over inflated prevalence of osteoporosis, particularly for spine osteoporosis. According to statistical modeling and when a local BMD reference is used, we tentatively recommend the cutpoint values for T-score of femoral neck, total hip, and spine to be approximately -2.7, -2.6, and -3.7 for Hong Kong Chinese women. Using radiographic osteoporotic vertebral fracture as a surrogate clinical endpoint, we empirically demonstrated that a femoral neck T-score of -2.77 for Chinese women was equivalent to -2.60 for Italian women, a spine T-score of -3.75 for Chinese women was equivalent to -2.44 for Italian women, and for Chinese men a femoral neck T-score of -2.77 corresponded to spine T-score of -3.37. For older Chinese men, we tentatively recommend the cutpoint values for T-score of femoral neck, total hip, and spine to be approximately -2.7, -2.6, and -3.2. With the BMD reference published by IKi et al. applied, T-score of femoral neck, total hip, and spine of -2.75, -3.0, and -3.9 for Japanese women will be more in line with the WHO osteoporosis definition. The revised definition of osteoporosis cutpoint T-scores for East Asians will allow a more meaningful international comparison of disease burden.

Geographic variation in bone mineral density and prevalent fractures in the Canadian longitudinal study on aging

Awareness of the prevalence of osteoporosis and fractures across jurisdictions can guide the development of local preventive programs and healthcare policies. We observed geographical variations in total hip bone mineral density and in the prevalence of major osteoporotic fractures across Canadian provinces, which persisted after adjusting for important covariates.

PURPOSE

We aimed to describe sex-specific total hip bone mineral density (aBMD) and prevalent major osteoporotic fractures (MOF) variation between Canadian provinces.

METHODS

We used baseline data from 21,227 Canadians (10,716 women, 10,511 men) aged 50-85 years in the Canadian Longitudinal Study on Aging (CLSA; baseline: 2012-2015). Linear and logistic regression models were used to examine associations between province of residence and total hip aBMD and self-reported MOF, stratified by sex. CLSA sampling weights were used to generate the prevalence and regression estimates.

RESULTS

The mean (SD) age of participants was 63.9 (9.1) years. The mean body mass index (kg/m2) was lowest in British Columbia (27.4 [5.0]) and highest in Newfoundland and Labrador (28.8 [5.3]). Women and men from British Columbia had the lowest mean total hip aBMD and the lowest prevalence of MOF. Alberta had the highest proportion of participants reporting recent falls (12.0%), and Manitoba (8.4%) the fewest (p-value=0.002). Linear regression analyses demonstrated significant differences in total hip aBMD: women and men from British Columbia and Alberta, and women from Manitoba and Nova Scotia had lower adjusted total hip aBMD than Ontario (p-values<0.02). Adjusted odds ratios (95% confidence intervals, CI) for prevalent MOF were significantly lower in women from British Columbia (0.47 [95% CI: 0.32; 0.69]) and Quebec (0.68 [95% CI: 0.48; 0.97]) and in men from British Columbia (0.40 [95% CI:0.22; 0.71]) compared to Ontario (p-values<0.03). Results were similar when adjusting for physical performance measures and when restricting the analyses to participants who reported White race/ethnicity.

CONCLUSION

Geographical variations in total hip aBMD and in the prevalence of MOF between provinces persisted after adjusting for important covariates which suggests an association with unmeasured individual and environmental factors.

Clinical Use of Trabecular Bone Score: The 2023 ISCD Official Positions

Osteoporosis can currently be diagnosed by applying the WHO classification to bone mineral density (BMD) assessed by dual-energy x-ray absorptiometry (DXA). However, skeletal factors other than BMD contribute to bone strength and fracture risk. Lumbar spine TBS, a grey-level texture measure which is derived from DXA images has been extensively studied, enhances fracture prediction independent of BMD and can be used to adjust fracture probability from FRAX® to improve risk stratification. The purpose of this International Society for Clinical Densitometry task force was to review the existing evidence and develop recommendations to assist clinicians regarding when and how to perform, report and utilize TBS. Our review concluded that TBS is most likely to alter clinical management in patients aged ≥ 40 years who are close to the pharmacologic intervention threshold by FRAX. The TBS value from L1-L4 vertebral levels, without vertebral exclusions, should be used to calculate adjusted FRAX probabilities. L1-L4 vertebral levels can be used in the presence of degenerative changes and lumbar compression fractures. It is recommended not to report TBS if extreme structural or pathological artifacts are present. Monitoring and reporting TBS change is unlikely to be helpful with the current version of the TBS algorithm. The next version of TBS software will include an adjustment based upon directly measured tissue thickness. This is expected to improve performance and address some of the technical factors that affect the current algorithm which may require modifications to these Official Positions as experience is acquired with this new algorithm.

Women's perspectives regarding osteoporosis, fracture risk, and pharmacologic treatment: a cross-sectional study

We assessed women's perspectives regarding early preventative therapy for osteoporosis. More than a third of early menopausal women were concerned about bone loss and future fractures, and approximately half were willing to take an intravenous or oral bisphosphonate around the time of menopause to preserve bone health.

PURPOSE

Bisphosphonate medications can prevent the substantial bone loss that occurs during early menopause, but little is known about whether women would accept bisphosphonate treatment at this time in their life, when imminent fracture risk is low. We assessed women's perspectives regarding bone loss, fracture risk, and preventative pharmacotherapy in early menopause.

METHODS

In this cross-sectional study, Canadian women aged ≥ 45 years were recruited via Facebook advertisement to complete an electronic survey. Primary outcome was the proportion of early menopausal respondents (≤ 5 years since final menstrual period) who were worried about bone loss and fractures. Secondary outcomes were the proportion of early menopausal women willing to accept pharmacologic intervention aimed at preventing either bone loss or future fractures. We compared responses between early menopausal women and older women (> 5 years since final menstrual period).

RESULTS

2033 women responded to the Facebook advertisement, 1195 eligible women (aged: 45 to 89 years) started the survey, and 966 completed it. Among early menopausal respondents (N = 98), 38 (42%) were worried about future fractures and 9 of 25 (36%) who had a prior bone mineral density scan were worried about their results. A total of 42 (47%) were willing to start medication to prevent fractures, and 48 (54%) would start medication to prevent bone loss. Responses were comparable between early menopausal women and older women.

CONCLUSION

Menopausal women are concerned about bone loss and fractures. Many women would consider early menopausal pharmacotherapy, with the goals of preserving bone health and lowering their risk of fractures.

Effect of Race/Ethnicity on United States FRAX Calculations and Treatment Qualification: A Registry-Based Study

Since 2008. the United States has had four race/ethnic fracture risk assessment tool (FRAX) calculators: White ("Caucasian"), Black, Asian, and Hispanic. The American Society for Bone and Mineral Research Task Force on Clinical Algorithms for Fracture Risk has been examining the implications of retaining race/ethnicity in the US FRAX calculators. To inform the Task Force, we computed FRAX scores according to each US calculator in 114,942 White, 485 Black, and 2816 Asian women (self-reported race/ethnicity) aged 50 years and older. We estimated treatment qualification based upon FRAX thresholds (3% for hip fracture, 20% for major osteoporotic fracture [MOF]). Finally, we examined measures for a hypothetical population-based FRAX calculator derived as the weighted mean for the US population based upon US Census Bureau statistics. With identical inputs, the highest FRAX measurements were found with the White FRAX calculator, lowest measurements with the Black calculator, and intermediate measurements for the Asian and Hispanic calculators. The percentage of women with FRAX scores exceeding the hip fracture treatment threshold was 32.0% for White, 1.9% for Black, and 19.7% for Asian women; the MOF treatment threshold was exceeded for 14.9% of White, 0.0% of Black, and 3.5% of Asian women. Disparities in treatment qualification were reduced after considering additional criteria (fracture history and dual-energy X-ray absorptiometry [DXA] T-score -2.5 or lower). When fracture risk was recalculated for non-White women using the White FRAX calculator, mean values for Asian women slightly exceeded those for White women but for Black women remained substantially below those for White women. When using a single population-based FRAX calculator, the mean probability of fracture and treatment qualification increased for non-White women across the age range. In summary, use of a single population-based FRAX calculator, rather than existing US race/ethnic FRAX calculators, will reduce differences in treatment qualification and may ultimately enhance equity and access to osteoporosis treatment. © 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).

Osteoporosis and Fracture Risk among Older US Asian Adults

PURPOSE OF REVIEW

This review summarizes the current knowledge regarding osteoporosis and fracture among older US Asian adults.

RECENT FINDINGS

Asian adults have lower (areal) bone density than non-Hispanic White adults and thus are more likely to be diagnosed and treated for osteoporosis, despite their lower risk of hip fracture. The latter may relate to favorable characteristics in hip geometry, volumetric bone density, and bone microarchitecture; lower risk of falls; and other clinical factors. The fracture risk calculator FRAX accounts for the lower risk of hip fracture among US Asian adults. However, data on major osteoporotic fracture risk remain limited. Fracture rates also vary by Asian subgroup, which may have implications for fracture risk assessment. Furthermore, among women receiving bisphosphonate drugs, Asian race is a risk factor for atypical femur fracture, an uncommon complication associated with treatment duration. Recent clinical trial efficacy data pertaining to lower bisphosphonate doses and longer dosing intervals may be relevant for Asian adults. More research is needed to inform osteoporosis care of US Asian adults, including risk-benefit considerations and the optimal duration of bisphosphonate treatment. Greater evidence-based guidance for primary fracture prevention among US Asian adults will ensure health equity in the prevention of osteoporotic fractures.

Race and Ethnicity and Fracture Prediction Among Younger Postmenopausal Women in the Women's Health Initiative Study

Importance

The best approach to identify younger postmenopausal women for osteoporosis screening is uncertain. The Fracture Risk Assessment Tool (FRAX), which includes self-identified racial and ethnic information, and the Osteoporosis Self-assessment Tool (OST), which does not, are risk assessment tools recommended by US Preventive Services Task Force guidelines to identify candidates for bone mineral density (BMD) testing in this age group.

Objective

To compare the ability of FRAX vs OST to discriminate between younger postmenopausal women who do and do not experience incident fracture during a 10-year follow-up in the 4 racial and ethnic groups specified by FRAX.

Design, Setting, and Participants

This cohort study of Women's Health Initiative participants included 67 169 women (baseline age range, 50-64 years) with 10 years of follow-up for major osteoporotic fracture (MOF; including hip, clinical spine, forearm, and shoulder fracture) at 40 US clinical centers. Data were collected from October 1993 to December 2008 and analyzed between May 11, 2022, and February 23, 2023.

Main Outcomes and Measures

Incident MOF and BMD (in a subset of 4607 women) were assessed. The area under the receiver operating characteristic curve (AUC) for FRAX (without BMD information) and OST was calculated within each racial and ethnic category.

Results

Among the 67 169 participants, mean (SD) age at baseline was 57.8 (4.1) years. A total of 1486 (2.2%) self-identified as Asian, 5927 (8.8%) as Black, 2545 (3.8%) as Hispanic, and 57 211 (85.2%) as White. During follow-up, 5594 women experienced MOF. For discrimination of MOF, AUC values for FRAX were 0.65 (95% CI, 0.58-0.71) for Asian, 0.55 (95% CI, 0.52-0.59) for Black, 0.61 (95% CI, 0.56-0.65) for Hispanic, and 0.59 (95% CI, 0.58-0.59) for White women. The AUC values for OST were 0.62 (95% CI, 0.56-0.69) for Asian, 0.53 (95% CI, 0.50-0.57) for Black, 0.58 (95% CI, 0.54-0.62) for Hispanic, and 0.55 (95% CI, 0.54-0.56) for White women. For discrimination of femoral neck osteoporosis, AUC values were excellent for OST (range, 0.79 [95% CI, 0.65-0.93] to 0.85 [95% CI, 0.74-0.96]), higher for OST than FRAX (range, 0.72 [95% CI, 0.68-0.75] to 0.74 [95% CI, 0.60-0.88]), and similar in each of the 4 racial and ethnic groups.

Conclusions and Relevance

These findings suggest that within each racial and ethnic category, the US FRAX and OST have suboptimal performance in discrimination of MOF in younger postmenopausal women. In contrast, for identifying osteoporosis, OST was excellent. The US version of FRAX should not be routinely used to make screening decisions in younger postmenopausal women. Future investigations should improve existing tools or create new approaches to osteoporosis risk assessment for this age group.

Recommendations on screening for primary prevention of fragility fractures

BACKGROUND

Fragility fractures are a major health concern for older adults and can result in disability, admission to hospital and long-term care, and reduced quality of life. This Canadian Task Force on Preventive Health Care (task force) guideline provides evidence-based recommendations on screening to prevent fragility fractures in community-dwelling individuals aged 40 years and older who are not currently on preventive pharmacotherapy.

METHODS

We commissioned systematic reviews on benefits and harms of screening, predictive accuracy of risk assessment tools, patient acceptability and benefits of treatment. We analyzed treatment harms via a rapid overview of reviews. We further examined patient values and preferences via focus groups and engaged stakeholders at key points throughout the project. We used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach to determine the certainty of evidence for each outcome and strength of recommendations, and adhered to Appraisal of Guidelines for Research and Evaluation (AGREE), Guidelines International Network and Guidance for Reporting Involvement of Patients and the Public (GRIPP-2) reporting guidance.

RECOMMENDATIONS

We recommend "risk assessment-first" screening for prevention of fragility fractures in females aged 65 years and older, with initial application of the Canadian clinical Fracture Risk Assessment Tool (FRAX) without bone mineral density (BMD). The FRAX result should be used to facilitate shared decision-making about the possible benefits and harms of preventive pharmacotherapy. After this discussion, if preventive pharmacotherapy is being considered, clinicians should request BMD measurement using dual-energy x-ray absorptiometry (DXA) of the femoral neck, and re-estimate fracture risk by adding the BMD T-score into FRAX (conditional recommendation, low-certainty evidence). We recommend against screening females aged 40-64 years and males aged 40 years and older (strong recommendation, very low-certainty evidence). These recommendations apply to community-dwelling individuals who are not currently on pharmacotherapy to prevent fragility fractures.

INTERPRETATION

Risk assessment-first screening for females aged 65 years and older facilitates shared decision-making and allows patients to consider preventive pharmacotherapy within their individual risk context (before BMD). Recommendations against screening males and younger females emphasize the importance of good clinical practice, where clinicians are alert to changes in health that may indicate the patient has experienced or is at higher risk of fragility fracture.

Screening for the primary prevention of fragility fractures among adults aged 40 years and older in primary care: systematic reviews of the effects and acceptability of screening and treatment, and the accuracy of risk prediction tools

BACKGROUND

To inform recommendations by the Canadian Task Force on Preventive Health Care, we reviewed evidence on the benefits, harms, and acceptability of screening and treatment, and on the accuracy of risk prediction tools for the primary prevention of fragility fractures among adults aged 40 years and older in primary care.

METHODS

For screening effectiveness, accuracy of risk prediction tools, and treatment benefits, our search methods involved integrating studies published up to 2016 from an existing systematic review. Then, to locate more recent studies and any evidence relating to acceptability and treatment harms, we searched online databases (2016 to April 4, 2022 [screening] or to June 1, 2021 [predictive accuracy]; 1995 to June 1, 2021, for acceptability; 2016 to March 2, 2020, for treatment benefits; 2015 to June 24, 2020, for treatment harms), trial registries and gray literature, and hand-searched reviews, guidelines, and the included studies. Two reviewers selected studies, extracted results, and appraised risk of bias, with disagreements resolved by consensus or a third reviewer. The overview of reviews on treatment harms relied on one reviewer, with verification of data by another reviewer to correct errors and omissions. When appropriate, study results were pooled using random effects meta-analysis; otherwise, findings were described narratively. Evidence certainty was rated according to the GRADE approach.

RESULTS

We included 4 randomized controlled trials (RCTs) and 1 controlled clinical trial (CCT) for the benefits and harms of screening, 1 RCT for comparative benefits and harms of different screening strategies, 32 validation cohort studies for the calibration of risk prediction tools (26 of these reporting on the Fracture Risk Assessment Tool without [i.e., clinical FRAX], or with the inclusion of bone mineral density (BMD) results [i.e., FRAX + BMD]), 27 RCTs for the benefits of treatment, 10 systematic reviews for the harms of treatment, and 12 studies for the acceptability of screening or initiating treatment. In females aged 65 years and older who are willing to independently complete a mailed fracture risk questionnaire (referred to as "selected population"), 2-step screening using a risk assessment tool with or without measurement of BMD probably (moderate certainty) reduces the risk of hip fractures (3 RCTs and 1 CCT, n = 43,736, absolute risk reduction [ARD] = 6.2 fewer in 1000, 95% CI 9.0-2.8 fewer, number needed to screen [NNS] = 161) and clinical fragility fractures (3 RCTs, n = 42,009, ARD = 5.9 fewer in 1000, 95% CI 10.9-0.8 fewer, NNS = 169). It probably does not reduce all-cause mortality (2 RCTs and 1 CCT, n = 26,511, ARD = no difference in 1000, 95% CI 7.1 fewer to 5.3 more) and may (low certainty) not affect health-related quality of life. Benefits for fracture outcomes were not replicated in an offer-to-screen population where the rate of response to mailed screening questionnaires was low. For females aged 68-80 years, population screening may not reduce the risk of hip fractures (1 RCT, n = 34,229, ARD = 0.3 fewer in 1000, 95% CI 4.2 fewer to 3.9 more) or clinical fragility fractures (1 RCT, n = 34,229, ARD = 1.0 fewer in 1000, 95% CI 8.0 fewer to 6.0 more) over 5 years of follow-up. The evidence for serious adverse events among all patients and for all outcomes among males and younger females (<65 years) is very uncertain. We defined overdiagnosis as the identification of high risk in individuals who, if not screened, would never have known that they were at risk and would never have experienced a fragility fracture. This was not directly reported in any of the trials. Estimates using data available in the trials suggest that among "selected" females offered screening, 12% of those meeting age-specific treatment thresholds based on clinical FRAX 10-year hip fracture risk, and 19% of those meeting thresholds based on clinical FRAX 10-year major osteoporotic fracture risk, may be overdiagnosed as being at high risk of fracture. Of those identified as being at high clinical FRAX 10-year hip fracture risk and who were referred for BMD assessment, 24% may be overdiagnosed. One RCT (n = 9268) provided evidence comparing 1-step to 2-step screening among postmenopausal females, but the evidence from this trial was very uncertain. For the calibration of risk prediction tools, evidence from three Canadian studies (n = 67,611) without serious risk of bias concerns indicates that clinical FRAX-Canada may be well calibrated for the 10-year prediction of hip fractures (observed-to-expected fracture ratio [O:E] = 1.13, 95% CI 0.74-1.72, I2 = 89.2%), and is probably well calibrated for the 10-year prediction of clinical fragility fractures (O:E = 1.10, 95% CI 1.01-1.20, I2 = 50.4%), both leading to some underestimation of the observed risk. Data from these same studies (n = 61,156) showed that FRAX-Canada with BMD may perform poorly to estimate 10-year hip fracture risk (O:E = 1.31, 95% CI 0.91-2.13, I2 = 92.7%), but is probably well calibrated for the 10-year prediction of clinical fragility fractures, with some underestimation of the observed risk (O:E 1.16, 95% CI 1.12-1.20, I2 = 0%). The Canadian Association of Radiologists and Osteoporosis Canada Risk Assessment (CAROC) tool may be well calibrated to predict a category of risk for 10-year clinical fractures (low, moderate, or high risk; 1 study, n = 34,060). The evidence for most other tools was limited, or in the case of FRAX tools calibrated for countries other than Canada, very uncertain due to serious risk of bias concerns and large inconsistency in findings across studies. Postmenopausal females in a primary prevention population defined as <50% prevalence of prior fragility fracture (median 16.9%, range 0 to 48% when reported in the trials) and at risk of fragility fracture, treatment with bisphosphonates as a class (median 2 years, range 1-6 years) probably reduces the risk of clinical fragility fractures (19 RCTs, n = 22,482, ARD = 11.1 fewer in 1000, 95% CI 15.0-6.6 fewer, [number needed to treat for an additional beneficial outcome] NNT = 90), and may reduce the risk of hip fractures (14 RCTs, n = 21,038, ARD = 2.9 fewer in 1000, 95% CI 4.6-0.9 fewer, NNT = 345) and clinical vertebral fractures (11 RCTs, n = 8921, ARD = 10.0 fewer in 1000, 95% CI 14.0-3.9 fewer, NNT = 100); it may not reduce all-cause mortality. There is low certainty evidence of little-to-no reduction in hip fractures with any individual bisphosphonate, but all provided evidence of decreased risk of clinical fragility fractures (moderate certainty for alendronate [NNT=68] and zoledronic acid [NNT=50], low certainty for risedronate [NNT=128]) among postmenopausal females. Evidence for an impact on risk of clinical vertebral fractures is very uncertain for alendronate and risedronate; zoledronic acid may reduce the risk of this outcome (4 RCTs, n = 2367, ARD = 18.7 fewer in 1000, 95% CI 25.6-6.6 fewer, NNT = 54) for postmenopausal females. Denosumab probably reduces the risk of clinical fragility fractures (6 RCTs, n = 9473, ARD = 9.1 fewer in 1000, 95% CI 12.1-5.6 fewer, NNT = 110) and clinical vertebral fractures (4 RCTs, n = 8639, ARD = 16.0 fewer in 1000, 95% CI 18.6-12.1 fewer, NNT=62), but may make little-to-no difference in the risk of hip fractures among postmenopausal females. Denosumab probably makes little-to-no difference in the risk of all-cause mortality or health-related quality of life among postmenopausal females. Evidence in males is limited to two trials (1 zoledronic acid, 1 denosumab); in this population, zoledronic acid may make little-to-no difference in the risk of hip or clinical fragility fractures, and evidence for all-cause mortality is very uncertain. The evidence for treatment with denosumab in males is very uncertain for all fracture outcomes (hip, clinical fragility, clinical vertebral) and all-cause mortality. There is moderate certainty evidence that treatment causes a small number of patients to experience a non-serious adverse event, notably non-serious gastrointestinal events (e.g., abdominal pain, reflux) with alendronate (50 RCTs, n = 22,549, ARD = 16.3 more in 1000, 95% CI 2.4-31.3 more, [number needed to treat for an additional harmful outcome] NNH = 61) but not with risedronate; influenza-like symptoms with zoledronic acid (5 RCTs, n = 10,695, ARD = 142.5 more in 1000, 95% CI 105.5-188.5 more, NNH = 7); and non-serious gastrointestinal adverse events (3 RCTs, n = 8454, ARD = 64.5 more in 1000, 95% CI 26.4-13.3 more, NNH = 16), dermatologic adverse events (3 RCTs, n = 8454, ARD = 15.6 more in 1000, 95% CI 7.6-27.0 more, NNH = 64), and infections (any severity; 4 RCTs, n = 8691, ARD = 1.8 more in 1000, 95% CI 0.1-4.0 more, NNH = 556) with denosumab. For serious adverse events overall and specific to stroke and myocardial infarction, treatment with bisphosphonates probably makes little-to-no difference; evidence for other specific serious harms was less certain or not available. There was low certainty evidence for an increased risk for the rare occurrence of atypical femoral fractures (0.06 to 0.08 more in 1000) and osteonecrosis of the jaw (0.22 more in 1000) with bisphosphonates (most evidence for alendronate). The evidence for these rare outcomes and for rebound fractures with denosumab was very uncertain. Younger (lower risk) females have high willingness to be screened. A minority of postmenopausal females at increased risk for fracture may accept treatment. Further, there is large heterogeneity in the level of risk at which patients may be accepting of initiating treatment, and treatment effects appear to be overestimated.

CONCLUSION

An offer of 2-step screening with risk assessment and BMD measurement to selected postmenopausal females with low prevalence of prior fracture probably results in a small reduction in the risk of clinical fragility fracture and hip fracture compared to no screening. These findings were most applicable to the use of clinical FRAX for risk assessment and were not replicated in the offer-to-screen population where the rate of response to mailed screening questionnaires was low. Limited direct evidence on harms of screening were available; using study data to provide estimates, there may be a moderate degree of overdiagnosis of high risk for fracture to consider. The evidence for younger females and males is very limited. The benefits of screening and treatment need to be weighed against the potential for harm; patient views on the acceptability of treatment are highly variable.

SYSTEMATIC REVIEW REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO): CRD42019123767.

General Comorbidity Indicators Contribute to Fracture Risk Independent of FRAX: Registry-Based Cohort Study

CONTEXT

FRAX® estimates 10-year fracture probability from osteoporosis-specific risk factors. Medical comorbidity indicators are associated with fracture risk but whether these are independent from those in FRAX is uncertain.

OBJECTIVE

We hypothesized Johns Hopkins Aggregated Diagnosis Groups (ADG®) score or recent hospitalization number may be independently associated with increased risk for fractures.

METHODS

This retrospective cohort study included women and men age ≥ 40 in the Manitoba BMD Registry (1996-2016) with at least 3 years prior health care data and used linked administrative databases to construct ADG scores along with number of hospitalizations for each individual. Incident Major Osteoporotic Fracture and Hip Fracture was ascertained during average follow-up of 9 years; Cox regression analysis determined the association between increasing ADG score or number of hospitalizations and fractures.

RESULTS

Separately, hospitalizations and ADG score independently increased the hazard ratio for fracture at all levels of comorbidity (hazard range 1.2-1.8, all P < 0.05), irrespective of adjustment for FRAX, BMD, and competing mortality. Taken together, there was still a higher than predicted rate of fracture at all levels of increased comorbidity, independent of FRAX and BMD but attenuated by competing mortality. Using an intervention threshold of major fracture risk >20%, application of the comorbidity hazard ratio multiplier to the patient population FRAX scores would increase the number of treatment candidates from 8.6% to 14.4%.

CONCLUSION

Both complex and simple measures of medical comorbidity may be used to modify FRAX-based risk estimates to capture the increased fracture risk associated with multiple comorbid conditions in older patients.

Race/ethnic differences in the prevalence of osteoporosis, falls and fractures: a cross-sectional analysis of the Canadian Longitudinal Study on Aging

Most of the published epidemiology on osteoporosis is derived from White populations; still many countries have increasing ethno-culturally diverse populations, leading to gaps in the development of population-specific effective fracture prevention strategies. We describe differences in prevalent fracture and bone mineral density patterns in Canadians of different racial/ethnic backgrounds.

INTRODUCTION

We described prevalent fracture and bone mineral density (BMD) patterns in Canadians by their racial/ethnic backgrounds.

METHODS

For this cross-sectional analysis, we used the Canadian Longitudinal Study on Aging baseline data (2011-2015) of 22,091 randomly selected participants of Black, East Asian, South or Southeast Asian (SSEA) and White race/ethnic backgrounds, aged 45-85 years with available information on the presence or absence of self-reported prevalent low trauma fractures and femoral neck BMD (FNBMD) measurement. Logistic and linear regression models examined associations of race/ethnic background with fracture and FNBMD, respectively. Covariates included sex, age, height, body mass index (BMI), grip strength and physical performance score.

RESULTS

We identified 11,166 women and 10,925 men. Self-reported race/ethnic backgrounds were: 139 Black, 205 East Asian, 269 SSEA and 21,478 White. White participants were older (mean 62.5 years) than the other groups (60.5 years) and had a higher BMI (28.0 kg/m²) than both Asian groups, but lower than the Black group. The population-weighted prevalence of falls was 10.0%, and that of low trauma fracture was 12.0% ranging from 3.3% (Black) to 12.3% (White), with Black and SSEA Canadians having lower adjusted odds ratios (aOR) of low trauma fractures than White Canadians (Black, aOR = 0.3 [95% confidence interval: 0.1-0.7]; SSEA, aOR = 0.5 [0.3-0.8]). The mean (SD) FNBMD varied between groups: Black, 0.907 g/cm² (0.154); East Asian, 0.748 g/cm² (0.119); SSEA, 0.769 g/cm² (0.134); and White, 0.773 g/cm² (0.128). Adjusted linear regressions suggested that Black and both Asian groups had higher FNBMD compared to White.

CONCLUSION

Our results support the importance of characterizing bone health predictors in Canadians of different race/ethnic backgrounds to tailor the development of population-specific fracture prevention strategies.

Fracture risk in Asian-Canadian women is significantly over-estimated by the Canadian Association of Radiologists-Osteoporosis Canada risk prediction tool: retrospective cohort study

Fracture risk calculators may not be accurate for all ethnicity groups. The Manitoba bone density registry was used to test the Canadian CAROC tool for predicting fracture risk in Asian-Canadian women. The tool significantly over-estimated fracture risk, suggesting that it may not be ideal for Asian-Canadian patients.

PURPOSE

Health risk prediction tools based on largely White populations may lead to treatment inequity when applied to non-White populations where outcome rates differ. We examined the calibration of the Canadian Association of Radiologists-Osteoporosis Canada (CAROC) fracture risk prediction tool in self-identified Asian-Canadian women.

METHODS

Retrospective cohort study of women over age 50 using the Manitoba BMD Registry. At first BMD, the intake questionnaire collected self-identification of ethnicity and fracture risk factors. 10-year fracture risk was estimated using CAROC and categorized into low, medium, or high fracture risk. Linked administrative databases identified incident osteoporotic fractures. Observed fracture rates were compared between White and Asian-Canadians and compared to the original CAROC risk stratification.

RESULTS

There were 63,632 and 1703 women who self-identified as White-Canadian or Asian-Canadian, respectively, covering approximately 600,000 patient-years follow-up. There were 6588 incident fractures; a similar percentage of patients were assigned to each risk stratum at baseline by CAROC. A progressive rise in 10-year observed fracture rates occurred for each CAROC stratum in the White-Canadian population but much lower fracture rates than predicted in Asian-Canadian patients (p &lt; 0.001). Fracture incidence rate ratios were 1.9-2.6 fold higher in White- vs Asian-Canadian patients for all strata (p &lt; 0.001). In the CAROC moderate and high-risk categories, observed fracture rates in Asian-Canadian patients were typically lower than predicted, indicating poor model calibration.

CONCLUSION

In Asian-Canadian women, observed osteoporosis fracture rates are lower than predicted when using the CAROC tool. Over-estimation of fracture risk may influence shared decision-making discussions.

Apparent "Rapid Loss" After Short-Interval Bone Density Testing in Menopausal Women Is Usually a Measurement Artifact

CONTEXT

Medication may be considered when bone mineral density (BMD) loss is reported as "excessive."

OBJECTIVE

We hypothesized that the rate of BMD change between 2 serial tests demonstrates higher random variability at shorter vs longer intervals, misclassifying some women as "rapid losers."

METHODS

This retrospective observational cohort study in Manitoba, Canada included women aged > 55 years without osteoporosis medications or glucocorticoids. Using paired baseline (1998-2016) and repeat (2001-2018) BMD measurements, we estimated the distribution of annualized change (first to second BMD) at spine, hip, and femoral neck stratified by testing interval (2-2.9, 3-3.9,...9-9.9, ≥ 10.0 years). "Rapid annual bone loss" was defined as exceeding the 95th percentile for decreases from all measurement pairs. Odds ratios (OR) for rapid loss were estimated using regression models adjusted for age and clinical covariates.

RESULTS

From 7126 paired BMD measurements, mean annualized change was constant yet standard deviations in BMD change were > 2-fold greater with intervals of 2 to 2.9 years vs ≥ 10 years(P < 0.001). "Rapid annual loss" was seen in ~10% of short-interval tests vs < 1% of long-interval tests. ORs for "rapid loss" progressively declined with increasing testing interval (spine 15.3 [4.8-48.9], total hip 9.3 [4.4-19.5], femoral neck 18.7 [6.8-51.3] for a 2- to 2.9-year testing interval; referent ≥ 10 years).

CONCLUSION

There is a wider apparent range in annualized BMD loss with short-interval testing which greatly attenuates over longer intervals. BMD reports of "rapid loss" across shorter testing intervals likely reflect an artifact of BMD measurement error and should not be used as an indication for antifracture medication initiation.

Establishment of a preliminary FRAX®-based intervention threshold for rheumatoid arthritis–associated fragility fracture: a 3-year longitudinal, observational, cohort study

Background:

To establish a FRAX®-based prediction model for rheumatoid arthritis (RA)-associated fragility fracture.

Methods:

This study is a longitudinal, real-world, registry cohort study. Patients with RA were registered to start in September 2014. The baseline demographics, bone mineral density (BMD), and risk factors of osteoporosis or fragility fracture were recorded. Subsequent fragility fractures during the 3-year observation period were also recorded. We developed a fixed intervention threshold (FITD) to identify fractures by choosing an optimal cut-off point on the receiver operating characteristic (ROC) curve and FRAX®. Several models for intervention thresholds (IT), including fixed intervention threshold (Taiwan) (FITT), age-specific individual intervention threshold (IIT), and hybrid intervention threshold (HIT), were compared to evaluate which IT model will have better discriminative power.

Results:

As of December 2020, a total of 493 RA participants have completed the 3-year observation study. The mean age of the participants was 59.3 ± 8.7, and 116 (23.5%) new fragility fractures were observed during the study period. In terms of pairwise comparisons of area under the curve ( n, 95% confidence interval) in the ROC curve, the FITD (0.669, 0.610–0.727, p < 0.001) with a value of 22% in major osteoporotic fracture and FITT (0.640, 0.582–0.699, p < 0.001) is significantly better than reference, but not for IIT (0.543, 0.485–0.601, p = 0.165) and HIT (0.543, 0.485–0.601, p = 0.165).

Conclusion:

An optimal FIT is established for intervention decisions in RA-associated fragility fractures. This model can offer an easy and simple guide to aid RA caregivers to provide interventions to prevent fragility fractures in patients with RA.

Much lower prevalence and severity of radiographic osteoporotic vertebral fracture in elderly Hong Kong Chinese women than in age-matched Rome Caucasian women: a cross-sectional study

INTRODUCTION

Many earlier studies reported that East Asians and Caucasians have similar radiographic osteoporotic vertebral fracture (OVF) prevalence. Since elderly Chinese's osteoporotic hip fracture prevalence is half (or less than half) of that of their age-match Caucasians, we hypothesize that elderly Chinese's OVF prevalence could be only half, or even less than half, of that of their age-match Caucasians.

MATERIALS

Age-matched (mean: 74.1 years; range: 65-87 years) elderly women's radiographs (T4-L5) were from two OVF population-based epidemiological studies conducted in Hong Kong (n = 200) and in Rome (n = 200). All radiographs were double read by one reader in Hong Kong and one reader in Rome. Radiological osteoporotic vertebral deformity (ROVD) classification included no ROVD (grade 0), and ROVDs with < 20%, 20 ~ 25%, ≥ 25% ~ 1/3, ≥ 1/3 ~ 40%, ≥ 40% ~ 2/3, and ≥ 2/3 height loss (grade 1 ~ 6) as well as endplate/cortex fracture (ECF). Spinal deformity index (SDI) was calculated with each vertebra assigned a score of 0, 0.5, 1, 1.5, 2, 2.5, and 3 for no ROVD or ROVDs grade 1 ~ 6.

RESULTS

Seventy-seven (38.5%) Chinese subjects and 123 Italian subjects (61.5%) had ROVD respectively (p < 0.0001). Chinese subjects had ECF in 52 (26%) cases involving 100 vertebrae, while Italian subjects had ECF in 93 (47%) cases involving 230 vertebrae. ROVDs in Italian subjects tended to be more severe (total and mean SDI: 454.5 and 3.71 for Italian, and 212 and 2.72 for Chinese, p < 0.05), more likely to be multiple, more likely to have severe and collapsed grades. The slope of the relationship between age vs. SDI was steeper for the Italian subjects than for the Chinese subjects, suggesting ROVD severity developed faster for aging Italian subjects. A trend suggested earlier onset of ROVD among Italian.

CONCLUSION

OVFs in Chinese women tend to be less common, less severe, and less likely to have multiple fractures.

Differences in fracture prevalence and in bone mineral density between Chinese and White Canadians: the Canadian Multicentre Osteoporosis Study (CaMos)

Fracture determinants differ between Canadians of Chinese and White descent, the former constituting the second largest visible minority group in Canada. The results of this study support the importance of characterizing bone health predictors in Canadians of different ethnicity to improve population-specific fracture prevention and treatment strategies.

PURPOSE

We aimed to compare clinical risk factors, bone mineral density, prevalence of osteoporosis, and fractures between Chinese and White Canadians to identify ethnicity-specific risks.

METHODS

We studied 236 Chinese and 8945 White Canadians aged 25+ years from the Canadian Multicentre Osteoporosis Study (CaMos). The prevalence of osteoporosis using ethnicity-specific peak bone mass (PBM), and of prior and incident low trauma fractures were assessed and compared between groups. Linear regressions, adjusting for age and anthropometric measures, were used to examine the association between baseline and 5-year changes in BMD and ethnicity.

RESULTS

Chinese participants had shorter stature, lower BMI, and lower rate of falls than White participants. Adjusted models showed no significant differences in baseline BMD between ethnic groups except in younger men where total hip BMD was 0.059 g/cm² (0.009; 0.108) lower in Chinese. Adjusted 5-year BMD change at lumbar spine was higher in older Chinese women and men compared with Whites. When using Chinese-specific PBM, the prevalence of osteoporosis in Chinese women was 2-fold lower than when using that of White women The prevalence of fractures was higher in White women compared with Chinese with differences up to 14.5% (95% CI 9.2; 19.7) and 10.5% (95% CI 4.5-16.4) in older White men. Incident fractures were rare in young Chinese compared with White participants and not different in the older groups.

CONCLUSION

Our results support the importance of characterizing bone strength predictors in Chinese Canadians and the development of ethnicity-specific fracture prediction and prevention strategies.