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.

Previous fracture and subsequent fracture risk: a meta-analysis to update FRAX

A large international meta-analysis using primary data from 64 cohorts has quantified the increased risk of fracture associated with a previous history of fracture for future use in FRAX.

INTRODUCTION

The aim of this study was to quantify the fracture risk associated with a prior fracture on an international basis and to explore the relationship of this risk with age, sex, time since baseline and bone mineral density (BMD).

METHODS

We studied 665,971 men and 1,438,535 women from 64 cohorts in 32 countries followed for a total of 19.5 million person-years. The effect of a prior history of fracture on the risk of any clinical fracture, any osteoporotic fracture, major osteoporotic fracture, and hip fracture alone was examined using an extended Poisson model in each cohort. Covariates examined were age, sex, BMD, and duration of follow-up. The results of the different studies were merged by using the weighted β-coefficients.

RESULTS

A previous fracture history, compared with individuals without a prior fracture, was associated with a significantly increased risk of any clinical fracture (hazard ratio, HR = 1.88; 95% CI = 1.72-2.07). The risk ratio was similar for the outcome of osteoporotic fracture (HR = 1.87; 95% CI = 1.69-2.07), major osteoporotic fracture (HR = 1.83; 95% CI = 1.63-2.06), or for hip fracture (HR = 1.82; 95% CI = 1.62-2.06). There was no significant difference in risk ratio between men and women. Subsequent fracture risk was marginally downward adjusted when account was taken of BMD. Low BMD explained a minority of the risk for any clinical fracture (14%), osteoporotic fracture (17%), and for hip fracture (33%). The risk ratio for all fracture outcomes related to prior fracture decreased significantly with adjustment for age and time since baseline examination.

CONCLUSION

A previous history of fracture confers an increased risk of fracture of substantial importance beyond that explained by BMD. The effect is similar in men and women. Its quantitation on an international basis permits the more accurate use of this risk factor in case finding strategies.

Should vertebral fracture assessment be performed in Fracture Liaison Service patients with non-vertebral fracture?

Prior non-vertebral fractures, except of the ankle, are associated with increased likelihood of vertebral fracture. As knowledge of vertebral fracture presence may alter care, vertebral fracture assessment (VFA) is indicated in patients with prior fracture.

INTRODUCTION

Vertebral fractures are often unappreciated. It was recently advocated that all Fracture Liaison Service (FLS) patients have densitometric VFA performed. We evaluated the likelihood of vertebral fracture identification with VFA in patients with prior fracture using the Manitoba Bone Density database. METHODS : VFA was performed in patients with T-scores below - 1.5 and age 70 + (or younger with height loss or glucocorticoid use) obtaining bone densitometry in Manitoba from 2010 to 2018. Those with prior clinical vertebral fracture, pathologic fracture, or uninterpretable VFA were excluded. Vertebral fractures were identified using the modified ABQ method. Health records were assessed for non-vertebral fracture (excluding head, neck, hand, foot) diagnosis codes unassociated with trauma prior to DXA. Multivariable odds ratios (ORs) for vertebral fracture were estimated without and with adjustment for age, sex, body mass index, ethnicity, area of residence, income level, comorbidity score, diabetes mellitus, falls in the last year, glucocorticoid use, and lowest BMD T-score.

RESULTS

The study cohort consisted of 12,756 patients (94.4% women) with mean (SD) age 75.9 (6.8) years. Vertebral fractures were identified in 1925 (15.1%) overall. Vertebral fractures were significantly more likely (descending order) in those with prior pelvis, hip, humerus, other sites, and forearm, but not ankle fracture. There was modest attenuation with covariate adjustment but statistical significance was maintained.

CONCLUSIONS

Prior hip, humerus, pelvis, forearm, and other fractures are associated with an increased likelihood of previously undiagnosed vertebral fracture, information useful for risk stratification and monitoring. These data support recommending VFA in FLS patients who are age 70 + with low BMD.

Update of the fracture risk prediction tool FRAX: a systematic review of potential cohorts and analysis plan

We describe the collection of cohorts together with the analysis plan for an update of the fracture risk prediction tool FRAX with respect to current and novel risk factors. The resource comprises 2,138,428 participants with a follow-up of approximately 20 million person-years and 116,117 documented incident major osteoporotic fractures.

INTRODUCTION

The availability of the fracture risk assessment tool FRAX® has substantially enhanced the targeting of treatment to those at high risk of fracture with FRAX now incorporated into more than 100 clinical osteoporosis guidelines worldwide. The aim of this study is to determine whether the current algorithms can be further optimised with respect to current and novel risk factors.

METHODS

A computerised literature search was performed in PubMed from inception until May 17, 2019, to identify eligible cohorts for updating the FRAX coefficients. Additionally, we searched the abstracts of conference proceedings of the American Society for Bone and Mineral Research, European Calcified Tissue Society and World Congress of Osteoporosis. Prospective cohort studies with data on baseline clinical risk factors and incident fractures were eligible.

RESULTS

Of the 836 records retrieved, 53 were selected for full-text assessment after screening on title and abstract. Twelve cohorts were deemed eligible and of these, 4 novel cohorts were identified. These cohorts, together with 60 previously identified cohorts, will provide the resource for constructing an updated version of FRAX comprising 2,138,428 participants with a follow-up of approximately 20 million person-years and 116,117 documented incident major osteoporotic fractures. For each known and candidate risk factor, multivariate hazard functions for hip fracture, major osteoporotic fracture and death will be tested using extended Poisson regression. Sex- and/or ethnicity-specific differences in the weights of the risk factors will be investigated. After meta-analyses of the cohort-specific beta coefficients for each risk factor, models comprising 10-year probability of hip and major osteoporotic fracture, with or without femoral neck bone mineral density, will be computed.

CONCLUSIONS

These assembled cohorts and described models will provide the framework for an updated FRAX tool enabling enhanced assessment of fracture risk (PROSPERO (CRD42021227266)).

Improved fracture risk prediction by adding VFA-identified vertebral fracture data to BMD by DXA and clinical risk factors used in FRAX

Vertebral fracture (VF) is a strong predictor of subsequent fracture. In this study of older women, VF, identified by dual-energy X-ray absorptiometry (DXA) vertebral fracture assessment (VFA), were associated with an increased risk of incident fractures and had a substantial impact on fracture probability, supporting the utility of VFA in clinical practice.

PURPOSE

Clinical and occult VF can be identified using VFA with dual-energy X-ray absorptiometry (DXA). The aim of this study was to investigate to what extent VFA-identified VF improve fracture risk prediction, independently of bone mineral density (BMD) and clinical risk factors used in FRAX.

METHODS

A total of 2852 women, 75-80 years old, from the prospective population-based study SUPERB cohort, were included in this study. At baseline, BMD was measured by DXA, VF diagnosed by VFA, and questionnaires used to collect data on risk factors for fractures. Incident fractures were captured by X-ray records or by diagnosis codes. An extension of Poisson regression was used to estimate the association between VFA-identified VF and the risk of fracture and the 5- and 10-year probability of major osteoporotic fracture (MOF) was calculated from the hazard functions for fracture and death.

RESULTS

During a median follow-up of 5.15 years (IQR 4.3-5.9 years), the number of women who died or suffered a MOF, clinical VF, or hip fracture was 229, 422, 160, and 124, respectively. A VFA-identified VF was associated with an increased risk of incident MOF (hazard ratio [HR] = 1.78; 95% confidence interval [CI] 1.46-2.18), clinical VF (HR = 2.88; 95% [CI] 2.11-3.93), and hip fracture (HR = 1.67; 95% [CI] 1.15-2.42), adjusted for age, height, and weight. For women at age 75 years, a VFA-identified VF was associated with 1.2-1.4-fold greater 10-year MOF probability compared with not taking VFA into account, depending on BMD.

CONCLUSION

Identifying an occult VF using VFA has a substantial impact on fracture probability, indicating that VFA is an efficient method to improve fracture prediction in older women.

Time since prior fracture affects mortality at the time of clinical assessment: a registry-based cohort study

Fractures are associated with increased long-term mortality in patients surviving to undergo baseline DXA. Notably, excess mortality risk does not decline with increasing time since prior hip or humerus fractures, even after accounting for comorbid medical conditions and other risk factors.

INTRODUCTION

Mortality risk increases following most types of fracture. In routine clinical practice, patients with prior fractures seen for dual-energy X-ray absorptiometry scan (DXA) are "survivors;" whether they remain at increased mortality risk is unknown. We tested the association between prior fracture and all-cause mortality, stratified by time since fracture, in patients undergoing baseline DXA.

METHODS

We conducted a DXA registry-based cohort study and linked to population-based health services data for the Province of Manitoba, Canada. We identified women and men ≥ 40 years with minimum 10 years of prior healthcare coverage undergoing baseline DXA and ascertained prior fracture codes since 1984 and mortality to 2017. Time since prior fracture was calculated between the clinical encounter for the fracture and baseline DXA (index date). Cox proportional hazards models estimated hazard ratios for all-cause mortality in those with compared to those without prior fracture adjusted for (1) age and sex, and (2) age, sex, comorbidities, and other covariates.

RESULTS

The study cohort consisted of 74,474 individuals (mean age 64.6 years, 89.7% female). During mean follow-up 9.2 years, we ascertained 14,923 (20.0%) deaths. Except for forearm fractures, all fracture sites were associated with increased mortality risk compared to those without prior fracture, even after multivariable adjustment. Excess mortality risk tended to decline slightly with time since fracture and was no longer significant > 10 years after vertebral fracture. However, excess mortality persisted > 10 years following hip or humerus fracture.

CONCLUSIONS

Prior fractures are associated with increased long-term mortality in patients surviving to undergo baseline DXA. Excess mortality risk does not decline with time since prior hip or humerus fractures, after accounting for potential confounders. Fracture prevention may have important long-term benefits preserving life expectancy.

Predictive performance of the Garvan Fracture Risk Calculator: a registry-based cohort study

The G arvan Fracture Risk Calculator predicts risk of osteoporotic fractures. We evaluated its predictive performance in 16,682 women and 2839 men from Manitoba, Canada, and found significant risk stratification, with a strong gradient across scores. The tool outperformed clinical risk factors and bone mineral density for fracture risk stratification.

INTRODUCTION

The optimal model for fracture risk estimation to guide treatment decision-making remains controversial. Our objective was to evaluate the predictive performance of the Garvan Fracture Risk Calculator (FRC) in a large clinical registry from Manitoba, Canada.

METHODS

Using the population-based Manitoba Bone Mineral Density (BMD) registry, we identified women and men aged 50-95 years undergoing baseline BMD assessment from September 1, 2012, onwards. Five-year Garvan FRC predictions were generated from clinical risk factors (CRFs) with and without femoral neck BMD. We identified incident non-traumatic osteoporotic fractures (OFs) and hip fractures (HFs) from population-based healthcare data sources to March 31, 2018. Fracture risk was assessed from area under the receiver operating characteristic curve (AUROC). Cox regression analysis and calibration ratios (5-year observed/predicted) were assessed for risk quintiles. All analyses were sex stratified.

RESULTS

We included 16,682 women (mean age 66.6 + / - SD 8.7 years) and 2839 men (mean age 68.7 + / - SD 10.2 years). During a mean observation time of 2.6 years, incident OFs were identified in 681 women and 140 men and HFs in 199 women and 22 men. AUROC showed significant fracture risk stratification with the Garvan FRC. Tool predictions without BMD were better than from age or decreasing weight, and the tool with BMD performed better than BMD alone. Garvan FRC with BMD performed better than without BMD, especially for HF prediction (AUROC 0.86 in women, 0.82 in men). There was a strong gradient of increasing risk across Garvan FRC quintiles (highest versus lowest, hazard ratios women 5.75 and men 3.43 for any OF; women 101.6 for HF). Calibration differences were noted, with both over- and underestimation in risk.

CONCLUSIONS

Garvan FRC outperformed CRFs and BMD alone for fracture risk stratification, particularly for HF, but may require recalibration for accurate predictions in this population.

Fracture risk assessment by the FRAX model

The introduction of the FRAX algorithms has facilitated the assessment of fracture risk on the basis of fracture probability. FRAX integrates the influence of several well-validated risk factors for fracture with or without the use of bone mineral density. Since age-specific rates of fracture and death differ across the world, FRAX models are calibrated with regard to the epidemiology of hip fracture (preferably from national sources) and mortality (usually United Nations sources). Models are currently available for 73 nations or territories covering more than 80% of the world population. FRAX has been incorporated into more than 80 guidelines worldwide, although the nature of this application has been heterogeneous. The limitations of FRAX have been extensively reviewed. Arithmetic procedures have been proposed in order to address some of these limitations, which can be applied to conventional FRAX estimates to accommodate knowledge of dose exposure to glucocorticoids, concurrent data on lumbar spine bone mineral density, information on trabecular bone score, hip axis length, falls history, type 2 diabetes, immigration status and recency of prior fracture.

Time dependency in early major osteoporotic and hip re-fractures in women and men aged 50 years and older: a population-based observational study

We analyzed patterns in recurrent major osteoporotic fracture (MOF) following a first major osteoporotic fracture in a large population-based cohort. Re-fracture risk remained elevated over 10 years, with only modest and inconsistent attenuation in risk over time.

INTRODUCTION

Recurrent fracture risk remains elevated for up to 25 years, and is reportedly highest in the initial 2 years (imminent risk). Our aim was to characterize early time dependency in re-fracture rates up to 10 years after a first fracture in a population-based cohort.

METHODS

Using Province of Manitoba (Canada) healthcare databases, we performed a matched cohort study in 22,105 women (mean age 74.1 ± 10.6 years) and 7589 men (mean age 71.8 ± 11.2 years) after a first MOF (age ≥ 50 years) during 1989-2006 and matched fracture-free controls (3 for each case). Incident fractures were ascertained over the next 10 years. Fracture rate ratios (RRs, cases versus controls) stratified by sex and age were computed, and tested for linear trend using linear regression. Joinpoint regression was performed to determine non-linear change in fracture rates over time, with particular attention to the first 2-year post-fracture.

RESULTS

RRs for incident MOF and hip fracture exceeded unity for the primary analyses in all subgroups and follow-up intervals. There was a tendency of RRs to decline over time, but this was inconsistent. Absolute rates per 100,000 person-years for fracture cases were consistently greater than for controls in all subgroups and observation times. Among fracture cases, there was a tendency for rates to decline gradually in all subgroups except younger women, but these temporal trends appeared monotonic without an inflection at 2 years. Joinpoint regression analyses did not detect an inflection in risk between the first 2 years and subsequent years. No significant time dependency was seen for incident hip fracture.

CONCLUSIONS

MOF and hip re-fracture risk was elevated in all age and sex subgroups over 10 years. There was inconsistent and only modest time dependency in early MOF risk, most evident in women after age 65 years. No strong transition in risk was seen between the first 2-year post-fracture and subsequent years.

Long-term risk of subsequent major osteoporotic fracture and hip fracture in men and women: a population-based observational study with a 25-year follow-up

The risk of subsequent major osteoporotic and hip fracture following an initial fracture was increased in both sexes over 25 years, with modest time-dependent attenuation. This risk was highest in men, underscoring the importance of targeted treatment strategies particularly in this under-treated population.

INTRODUCTION

The risk of subsequent fractures is increased following an index fracture, and declines over time. We aimed to determine whether this risk was sustained over 25 years and evolved similarly in men and women.

METHODS

Using population-based databases, we performed a matched cohort study in 16,876 men and 39,230 women ≥ 50 years who sustained an index fracture during 1989-2006. Rates of subsequent major osteoporotic fractures (MOF) and hip fractures until 2016 were compared to rates for matched controls (n = 160,983). Age- and sex-stratified cumulative incidences to 25 years were estimated in the presence of competing mortality. Hazard ratios (HRs) with 95% confidence intervals (CI) for subsequent fractures were estimated for each on the first 15 years of follow-up with a final category ≥ 15 years, adjusted for comorbidities.

RESULTS

Risk for MOF and hip fractures remained elevated up to 25 years in both sexes. The cumulative incidence of fractures was higher in cases vs controls in both sexes and across all age categories except in those > 90 years. Crude rate ratios for subsequent MOF were 2.5 (95% CI 2.3-2.7) in men and 1.6 (95% CI 1.6-1.7) in women and were higher in the younger age groups. Adjusted HRs (aHRs) for subsequent MOF were higher in men than in women in the first year (men aHR 2.6, 95% CI 2.1-3.3; women aHR 1.6, 95% CI 1.4-1.7).

CONCLUSIONS

The risk of subsequent fractures following an initial fracture was increased over 25 years and the magnitude of risk was initially greater in men than in women.

Simulated effects of early menopausal bone mineral density preservation on long-term fracture risk: a feasibility study

Prevention of early menopausal bone loss may reduce the future burden of osteoporosis. In this modelling exercise, an osteoporosis prevention strategy involving 5-year infusions of zoledronic acid, beginning early in menopause, reduced long-term fracture risk and the proportion of aging women with femoral neck densitometric osteoporosis. This strategy warrants further evaluation.

INTRODUCTION

Preventing early menopausal bone loss may substantially reduce the future burden of osteoporosis. We modelled the effects of infrequent zoledronic acid infusions on long-term fracture risk.

METHODS

Data from the Canadian Multicentre Osteoporosis Study (CaMos) were used to determine the expected natural history of femoral neck areal bone mineral density (BMD) and fracture risk (using FRAX®) from ages 50-80 for women with no antiresorptive drug exposures. We modelled the effects of three infusions of zoledronic acid (at ages 50, 55, 60) on long-term fracture risk, assuming this intervention would preserve BMD until age 65 years, followed by losses mirroring early menopausal BMD loss.

RESULTS

At age 65, untreated women and zoledronic acid recipients had expected mean (SD) femoral neck T-scores of - 1.5(1.0) and - 0.8(1.0), 10-year major osteoporotic fracture (MOF) risks of 9.8%(5.0) and 8.0%(3.7) and hip fracture risks of 1.7%(2.4) and 0.8%(1.2), respectively. At age 80, untreated women and zoledronic acid recipients had expected femoral neck T-scores of - 1.9(0.9) and - 1.4(0.9), MOF risks of 17.9%(8.2) and 14.9%(6.4) and hip fracture risks of 6.3%(6.2) and 4.4%(4.5), respectively. The expected proportion of women with femoral neck T-score ≤ - 2.5 was 14.9% for untreated women and 3.8% for zoledronic acid recipients at age 65, increasing to 28.1% and 12.0%, respectively, at age 80. Numbers-needed-to-treat to prevent one case of densitometric osteoporosis were 9 at age 65 and 5 at age 80.

CONCLUSION

Infrequent infusions of zoledronic acid, initiated early in menopause, are expected to reduce long-term fracture risk and result in a substantial reduction in the proportion of women with densitometric osteoporosis after age 65.

The association of objectively ascertained sibling fracture history with major osteoporotic fractures: a population-based cohort study

We investigated the association of objectively ascertained sibling fracture history with major osteoporotic fracture (hip, forearm, humerus, or clinical spine) risk in a population-based cohort using administrative databases. Sibling fracture history is associated with increased major osteoporotic fracture risk, which has implications for fracture risk prediction.

INTRODUCTION

We aimed to determine whether objectively ascertained sibling fracture history is associated with major osteoporotic fracture (MOF; hip, forearm, humerus, or clinical spine) risk.

METHODS

This retrospective cohort study used administrative databases from the province of Manitoba, Canada, which has a universal healthcare system. The cohort included men and women 40+ years between 1997 and 2015 with linkage to at least one sibling. The exposure was sibling MOF diagnosis occurring after age 40 years and prior to the outcome. The outcome was incident MOF identified in hospital and physician records using established case definitions. A multivariable Cox proportional hazards regression model was used to estimate the risk of MOF after adjustment for known fracture risk factors.

RESULTS

The cohort included 217,527 individuals; 91.9% were linked to full siblings (siblings having the same father and mother) and 49.0% were females. By the end of the study period, 6255 (2.9%) of the siblings had a MOF. During a median follow-up of 11 years (IQR 5-15), 5235 (2.4%) incident MOF were identified in the study cohort, including 234 hip fractures. Sibling MOF history was associated with an increased risk of MOF (hazard ratio [HR] 1.67, 95% confidence interval [CI] 1.44-1.92). The risk was elevated in both men (HR 1.57, 95% CI 1.24-1.98) and women (HR 1.74, 95% CI 1.45-2.08). The highest risk was associated with a sibling diagnosis of forearm fracture (HR 1.81, 95% CI 1.53-2.15).

CONCLUSION

Sibling fracture history is associated with increased MOF risk and should be considered as a candidate risk factor for improving fracture risk prediction.

Cancer patients with fractures are rarely assessed or treated for osteoporosis: a population-based study

Among 4238 cancer and 16,418 cancer-free individuals with incident major non-traumatic fractures (hip, clinical vertebral, forearm, humerus), post-fracture osteoporosis care was equally poor for both groups, whether assessed from bone mineral density (BMD) testing, initiation of osteoporosis therapy or either intervention (BMD testing and/or osteoporosis therapy).

INTRODUCTION

Most individuals sustaining a fracture do not undergo evaluation and/or treatment for osteoporosis. Cancer survivors are at increased risk for osteoporosis and fracture. Whether cancer survivors experience a similar post-fracture "care gap" is unclear. Using population-based databases, we assessed whether cancer patients are evaluated and/or treated for osteoporosis after a major fracture.

METHODS

From the Manitoba Cancer Registry, we identified cancer cases (first cancer diagnosis between 1987 and 2013) and cancer-free controls with incident major non-traumatic fractures (from provincial physician billing claims and hospitalization databases). The outcomes were performance of BMD testing (from the BMD Registry), initiation of osteoporosis therapy (from drug dispensation database) or either intervention (BMD testing and/or osteoporosis therapy) in the 12 months post-fracture.

RESULTS

There were 4238 cancer and 16,418 cancer-free individuals who sustained a fracture after the index date (cancer diagnosis) and were followed for at least 1 year post-fracture. Subsequent BMD testing was performed in 11.0% of cancer cases versus 11.5% non-cancer controls (P = 0.43), osteoporosis treatment in 22.9% cancer cases versus 21.8% non-cancer controls (P = 0.15), and either testing or treatment in 28.9% cancer cases versus 28.4% non-cancer controls (P = 0.53). Predictors of BMD testing and/or initiation of therapy were similar for non-cancer and cancer patients. Post-fracture interventions were consistently used more frequently among women, older patients (age 50 years or older), those who sustained fractures in a later calendar period, and (for treatment) after vertebral fracture. Cancer-specific variables (cancer type, years from cancer diagnosis to fracture, specialty of care provider) showed only weak and inconsistent effects.

CONCLUSIONS

A large care gap exists among cancer patients who sustain a fracture, similar to the general population, whereby the evaluation or treatment for osteoporosis is seldom conducted. Care maps may need to be developed for cancer populations to improve post-fracture care.

The use of 2-, 5-, and 10-year probabilities to characterize fracture risk after a recent sentinel fracture

The increase in fracture risk associated with a recent fragility fracture is more appropriately captured using a 10-year fracture probability than 2- or 5-year probabilities.

INTRODUCTION

The recency of prior fractures affects subsequent fracture risk. The aim of this study was to quantify the effect of a recent sentinel fracture, by site, on the 2-, 5-, and 10-year probability of fracture.

METHODS

The study used data from the Reykjavik Study fracture register that documented prospectively all fractures at all skeletal sites in a large sample of the population of Iceland. Fracture probabilities were determined after a sentinel fracture (humeral, clinical vertebral, forearm and hip fracture) occurring within the previous 2 years and probabilities for a prior osteoporotic fracture irrespective of recency. The probability ratios were used to adjust fracture probabilities over a 2-, 5-, and 10-year time horizon.

RESULTS

As expected, probabilities decreased with decreasing time horizon. Probability ratios varied according to age and the site of sentinel fracture. Probability ratios to adjust for a prior fracture within the previous 2 years were higher the shorter the time horizon, but the absolute increases in fracture probabilities were much reduced. Thus, fracture probabilities were substantially lower with time horizons less than 10 years.

CONCLUSION

The 10-year probability of fractures is the appropriate metric to capture the impact of the recency of sentinel fractures. The probability ratios provide adjustments to conventional FRAX estimates of fracture probability for recent sentinel fractures, adjustments which can readily inform clinical decision-making.

Frequency of normal bone measurement in postmenopausal women with fracture: a registry-based cohort study

This registry-based cohort study assessed the percentage of women with prior or incident fracture who had normal bone defined as a normal bone mineral density T-score and normal trabecular bone score (TBS). Inclusion of TBS reduced the percentage with normal bone. Normal bone measurement is rare in women with fracture.

INTRODUCTION

Some fractures occur in women with normal BMD. We hypothesized that adding trabecular bone score (TBS) to DXA would (1) demonstrate that few women with fracture have normal bone, i.e., normal BMD T-score and TBS and (2) increase the percentage of women with fracture that have abnormal bone defined as a BMD T-score ≤ - 2.5 or low TBS.

METHODS

The public healthcare system in Manitoba, Canada, makes it possible to link clinical DXA data to population databases. This study included all women age 50+ with a first DXA from February 1999 to March 2018 with valid BMD, TBS, and fracture data. Bone status was defined as Normal = BMD T-score of the spine, femoral neck, and total femur ≥ - 1.0 AND TBS > 1.31; Abnormal = BMD T-score ≤ - 2.5 OR TBS < 1.23; and borderline = all others. Analyses were stratified by age decade.

RESULTS

Among women with prior (n = 4649) or incident (n = 2547) fracture, bone status assessed by both BMD and TBS was normal in only 6% and 4%, respectively. In women with prior or incident hip fracture, normal bone was present in < 1%. The prevalence of normal bone declined (p trend < 0.001) with age as expected. BMD T-score osteoporosis was present in 40% with any prior and 46% with any incident fracture. BMD T-score osteoporosis was present in 65% and 60% with prior and incident hip fracture, respectively. Including TBS with BMD increased the percentage of women with abnormal bone to 61% and 68% for any prior or incident fracture and to 80% and 81% for prior or incident hip fracture, respectively (all p < 0.001).

CONCLUSION

Including TBS with BMD increases identification of abnormal bone in women with fracture compared with BMD alone. Normal bone is present in < 6% of women with any fracture and < 1% of those with hip fracture. What is thought to be normal bone in women with fracture is rarely normal.

Core principles for fracture prevention: North American Consensus from the National Osteoporosis Foundation, Osteoporosis Canada, and Academia Nacional de Medicina de Mexico

Core principles for fracture prevention address fundamental concepts for the evaluation and management of patients at risk for fracture. These are intended to form the foundation of clinical practice guidelines and represent a first step toward guideline harmonization.

INTRODUCTION

The large number of clinical practice guidelines for osteoporosis and discordance of recommendations has led to confusion among clinicians and patients, and likely contributes to the large osteoporosis treatment gap. We propose that stakeholder organizations reach agreement on fundamental principles in the management of osteoporosis and prevention of fracture as a first step toward a goal of guideline harmonization.

METHODS

The best available evidence, as interpreted by an ad hoc working group of expert representatives from major osteoporosis societies in North America, was considered in the development of core principles for skeletal healthcare. These principles were subsequently endorsed by the USA National Osteoporosis Foundation, Osteoporosis Canada, and Academia Nacional de Medicina de Mexico (National Academy of Medicine of Mexico).

RESULTS

Core principles are summarized here in bullet format. Categories include evaluation, lifestyle and nutrition, pharmacological therapy, and monitoring. A pathway forward to achieve guideline harmonization, at least in part, is proposed.

CONCLUSION

Greater concordance of recommendations for the care of patients at risk for fracture are expected to lead to improved patient care across jurisdictions, with a narrowing of the osteoporosis treatment gap and reduced burden of fractures.

Trabecular bone score in patients with chronic kidney disease

Patients with chronic kidney disease have high risk of osteoporotic fractures. Lower trabecular bone score (TBS) was associated with poorer kidney function and higher fracture risk when kidney function was normal. Addition of TBS to The Fracture Risk Assessment Tool with bone mineral density did not improve fracture risk prediction.

INTRODUCTION

We sought to determine whether trabecular bone score (TBS) either independently or adjusted for The Fracture Risk Assessment Tool (FRAX) could predict risk of major osteoporotic fractures (MOFs) in a large population-based sample of patients with all stages of chronic kidney disease (CKD).

METHODS

We used population-based administrative databases to identify patients above age 20 years who had dual-energy X-ray absorptiometry (DXA) scan and serum creatinine measured within 1 year, during the years 2005 to 2010. Patients were excluded if they were on dialysis or had a functioning renal transplant. We stratified patients by estimated glomerular filtration rate (eGFR). We collected femoral neck bone mineral density (BMD), lumbar spine TBS, incident major osteoporotic fractures (MOF) and hip fractures, and other clinical characteristics.

RESULTS

Among 8289 patients, there were 6224 (75.1%) with eGFR ≥ 60 mL/min/1.73 m², 1624 (19.6%) with eGFR 30-60 mL/min/1.73 m², and 441 (5.3%) with eGFR < 30 mL/min/1.73 m². There were 593 patients (7.2%) with MOFs and 163 (2.0%) with hip fractures. Lower TBS score was associated with increased risk of MOF and hip fractures across all eGFR strata in unadjusted Cox proportional hazards models but after adjusting for FRAX with BMD, lower TBS was only statistically significant for MOF prediction for eGFR ≥ 60 mL/min/1.73 m².

CONCLUSION

Lower TBS scores were associated with lower eGFR and increased fracture risk in patients with eGFR ≥ 60 mL/min/1.73 m². However, the addition of TBS to the FRAX score with BMD did not significantly improve fracture risk prediction in patients with CKD.

Bone densitometry worldwide: a global survey by the ISCD and IOF

In a global survey of fracture liaison services, most reported that DXA access met needs. However, adherence to basic DXA quality and reporting procedures was confirmed by only around 50% of institutions and many required education for operators/interpreters. Overall, there is significant variability in the access to, and quality of, DXA services worldwide.

INTRODUCTION

While the use of dual-energy X-ray absorptiometry (DXA) has been widely adopted worldwide for the assessment of bone mineral density, the quality of DXA facilities is unknown. To address this, a global survey of fracture liaison services (FLS) was conducted by the International Society for Clinical Densitometry (ISCD) and the International Osteoporosis Foundation (IOF) to assess the quality of their DXA facilities.

METHODS

A questionnaire for the accessibility and quality of DXA services was co-created by representatives of the ISCD and the IOF and made available to institutions who participated in the Capture the Fracture Best Practice Framework. From a list of 331 contacted invitees, 124 FLS centres responded; analyses were based on 121 centres with suitable data.

RESULTS

Over 70% of institutions reported that, for over 90% of the time, DXA access met service needs, and the scanning/reporting quality was perceived as excellent. However, 25% of DXA facilities reported not being accredited by a professional/governmental organization, and adherence to some basic DXA quality assurance and reporting procedures was confirmed by < 50% of services. Importantly, in excess of 50% of institutions stated that they desired ongoing education in osteoporosis and DXA for operators and interpreters.

CONCLUSION

There is significant variability in the access to and quality of DXA services for established FLS worldwide. Despite two decades of training initiatives in osteoporosis densitometry, many centres are falling short of the standards of the IOF-ISCD Osteoporosis Essentials criteria.

Correction to: Lean mass and lower limb muscle function in relation to hip strength, geometry and fracture risk indices in community-dwelling older women

The original version of this article, published on 14 December 2018, unfortunately contained a mistake.

Targeted bone density testing for optimizing fracture prevention in Canada

The Canadian FRAX® tool used without bone mineral density (BMD) is highly sensitive for identifying individuals qualifying for pharmacotherapy based upon an intervention threshold of 20% for major osteoporotic fracture risk (MOF) computed with BMD.

INTRODUCTION

This analysis was performed to inform initial BMD testing as part of Osteoporosis Canada's Guidelines Update for women and men at average risk, assuming a pharmacotherapy intervention threshold of 20% for FRAX® MOF computed with BMD.

METHODS

Women and men age 50 + without previous low-trauma fracture or high-risk medication use were identified in a BMD registry for the province of Manitoba, Canada. Fracture probability assessments with the Canadian FRAX® tool were computed without and with BMD (denoted MOF-clinical and MOF-BMD, respectively).

RESULTS

The study population consisted of 50,700 women (mean age 65.5 ± 9.4 years) and 4152 men (69.2 ± 10.0 years). FRAX MOF-clinical score was > 10% in 33.8% of women and 13.3% of men (P < 0.001). The median (interquartile range [IQR]) age for MOF-clinical to reach 10% in women was 70 (69-72) and 65 years (62-67) years in the absence and presence of additional FRAX clinical risk factors, respectively. In men, comparable ages were 83 years [82-86] and 76 [70-78] years. Using MOF-BMD of 20% as the intervention threshold, 4.3% of women and 0.7% of men qualified for treatment. MOF-clinical > 10% had high sensitivity to identify those qualifying for treatment (99.3% in women and 99.1% in men). An age-based rule ("BMD testing is indicated at age 70 if no additional FRAX clinical risk factors are present, or at age 65 if one or more clinical risk factors exists") gave similarly high sensitivity (women 99.9% and men > 99.9%).

CONCLUSIONS

FRAX without BMD offers an effective strategy to identify individuals meeting the current Canadian treatment threshold based upon FRAX® with BMD (≥ 20%). Moreover, this can be operationalized using simple age cutoffs of 70 years in the absence of additional clinical risk factors and 65 years in the presence of additional clinical risk factors.

Measured height loss predicts incident clinical fractures independently from FRAX: a registry-based cohort study

During median follow-up 6.0 years in 11,495 individuals, prior absolute and annualized measured height loss was significantly greater in those with subsequent incident fracture compared with those without incident fracture.

PURPOSE

FRAX® accepts baseline height and weight as input variables, but does not consider change in these parameters over time.

AIM

To evaluate the association between measured height or weight loss on subsequent fracture risk adjusted for FRAX scores, risk factors, and competing mortality.

METHODS

Using a dual-energy x-ray absorptiometry (DXA) registry for the Province of Manitoba, Canada, we identified women and men age 40 years or older with height and weight measured at the time of two DXA scans. Cox regression analyses were performed to test for a covariate-adjusted association between prior height and weight loss with incident fractures occurring after the second scan using linked population-based healthcare data.

RESULTS

The study population consisted of 11,495 individuals (average age 68.0 ± 9.9 years, 94.6% women). During median follow-up 6.0 years, records demonstrated incident major osteoporotic fracture (MOF) in 869 individuals, hip fractures in 265, clinical vertebral fractures in 207, and any fracture in 1203. Prior height loss was significantly greater in individuals with fracture compared with those without fracture, regardless of fracture site. Mortality was greater in those with prior height loss (HR per SD 1.11, 95% CI 1.06-1.17) or weight loss (HR per SD 1.26, 95% CI 1.19-1.32). Each SD in height loss was associated with increased fracture risk (MOF 12-17%, hip 8-19%, clinical vertebral 28-37%, any fracture 14-19%). Prior weight loss was associated with 21-30% increased risk for hip fracture, but did not increase risk for other fractures. Height loss of 3.0 cm or greater more than doubled the risk for subsequent fracture.

CONCLUSIONS

Prior height loss is associated with a small but significant increase in risk of incident fracture at all skeletal sites independent of other clinical risk factors and competing mortality as considered by FRAX. Prior weight loss only increases risk for subsequent hip fracture.

Testing a theoretical model of imminent fracture risk in elderly women: an observational cohort analysis of the Canadian Multicentre Osteoporosis Study

We examined the underlying relationship between fracture risk factors and their imminent risk. Results suggested that having past year fracture, worse past year general health, worse past year physical functioning, and lower past year BMD T-score directly predicted higher imminent fracture risk. Past year falls indirectly predicted imminent risk through physical functioning and general health.

INTRODUCTION

This study aimed to examine direct and indirect effects of several factors on imminent (1 year) fracture risk.

METHODS

Data from women age 65 and older from population-based Canadian Multicentre Osteoporosis Study were used. Predictors were identified from study years 5 and 10, and imminent fracture data (1-year fracture) came from years 6 and 11 (year 5 predicts year 6, year 10 predicts year 11). A structural equation model (SEM) was used to test the theoretical construct. General health and physical functioning were measured as latent variables using items from the 36-Item Short Form Health Survey (SF-36) and bone mineral density (BMD) T-score was a latent variable based on observed site-specific BMD data (spine L1-L4, femoral neck, total hip). Observed variables were fractures and falls. Model fit was evaluated using root mean square error of approximation (RMSEA), Tucker Lewis index (TLI), and comparative fit index (CFI).

RESULTS

The analysis included 3298 women. Model fit tests showed that the SEM fit the data well; χ²(172) = 1122.10 < .001, RMSEA = .03, TLI = .99, CFI = .99. Results suggested that having past year fracture, worse past year general health, worse past year physical functioning, and lower past year BMD T-score directly predicted higher risk of fracture in the subsequent year (p < .001). Past year falls had a statistically significant but indirect effect on imminent fracture risk through physical functioning and general health (p < .001).

CONCLUSIONS

We found several direct and indirect pathways that predicted imminent fracture risk in elderly women. Future studies should extend this work by developing risk scoring methods and defining imminent risk thresholds.

Effects of long-term inhaled corticosteroid treatment on fragility fractures in older women: the Manitoba BMD registry study

The effects of inhaled corticosteroids (ICS) on fracture risk in older women with chronic respiratory diseases are not well established. Our results indicate long-term ICS use in this population does not increase the risk of major osteoporotic fracture. This finding further elucidates the long-term safety of ICS in older women.

INTRODUCTION

Inhaled corticosteroids (ICS) are frequently used in older women with chronic respiratory diseases. There is insufficient evidence regarding the association between long-term ICS use and the risk of fragility fractures in this population.

METHODS

We used linked Manitoba health administrative databases and the provincial bone mineral density (BMD) registry (1996-2013) to identify women ≥ 40 years of age with asthma and/or chronic obstructive pulmonary disease (COPD) within 3 years preceding the baseline BMD test. We followed them until the first major osteoporotic fracture or end of study, whichever came first. ICS use, stratified by exposure tertiles, was measured within the 12-month period following the baseline BMD test (by total days and quantity, primary outcome), and over the entire follow-up period (by medication possession ratio (MPR) and average annual dose, secondary outcome). The hazard ratio of fracture with ICS use was estimated using a Cox proportional hazards model, controlling for baseline determinants of fracture.

RESULTS

Of 6880 older women with asthma (38%) or COPD (62%), 810 (12%) experienced a major osteoporotic fracture over a mean follow-up of 7.7 years (SD = 3.9). ICS use at any tertile was not associated with an increased risk of fracture (dispensed days, p = 0.90; dispensed quantity, p = 0.67). Similarly, ICS use at any tertile during the entire follow-up period was not associated with an increased risk of fracture (MPR, p = 0.62; average annual dose, p = 0.58).

CONCLUSION

Our findings do not support an increased risk of major osteoporotic fracture in older women with chronic respiratory diseases due to long-term ICS use.

Patient engagement in clinical guidelines development: input from > 1000 members of the Canadian Osteoporosis Patient Network

Patient engagement in clinical guidelines development is essential. The results of a self-administered online survey identified themes important to people living with osteoporosis and will inform the development of Osteoporosis Canada clinical guidelines recommendations.

INTRODUCTION

Patient engagement is essential in the development of high-quality and relevant guidelines for osteoporosis management. Osteoporosis Canada (OC) is updating its national clinical practice guidelines in collaboration with people living with osteoporosis in the process.

METHODS

Using electronic mail, we contacted 6937 members of the Canadian Osteoporosis Patient Network (COPN) to provide input on the selection of relevant content, outcomes, and research questions via a self-administered online survey. Close-ended questions were analyzed using descriptive statistics, and conventional content analysis was conducted for open-ended questions.

RESULTS

A total of 1108 individuals completed the survey (97% women, 86% stated they lived with osteoporosis). Most participants considered it critical to have recommendations on physical activity and exercise (74%), fall prevention (69%), nutrition (68%), and initial bone mineral density testing (67%). In addition to preventing fractures, over 75% of respondents stated that consideration of preserving quality of life and ability to perform daily activities, preventing admission to long-term care and fracture-related death, and avoiding serious harms from medications were essential outcomes to consider in evaluating the evidence. In terms of selection of research questions, seven themes emerged from the content analysis including pharmacotherapy, screening and monitoring, diet and supplements, education, exercise, alternative therapies, and pain management.

CONCLUSIONS

Patients emphasized that autonomy, mobility, and quality of life are highly valued outcomes and must be integral to practice guideline development. As expected, guidance on pharmacotherapy, screening and monitoring, and fracture prevention were priorities identified to be included in osteoporosis management guidelines.

Fracture prediction from self-reported falls in routine clinical practice: a registry-based cohort study

A simple question construct regarding number of falls in the previous year, ascertained by a single question, was strongly associated with incident fractures in routine clinical practice using a population-based dual-energy X-ray absorptiometry (DXA) registry.

INTRODUCTION

There is conflicting evidence from research cohorts that falls independently increase fracture risk. We examined the independent effects of falls on subsequent fractures in a large clinical registry of bone mineral density (BMD) results for the Province of Manitoba, Canada that has been systematically collecting self-reported falls information since September 1, 2012.

METHODS

The study population consisted of 24,943 women and men aged 40 years and older (mean age 65.5 ± 10.2 years) with fracture probability assessment (FRAX), self-reported falls for the previous year (categorized as none, 1, 2, or > 3) and fracture outcomes. Adjusted hazard ratios (HR) with 95 confidence intervals (CI) for time to fracture were estimated using Cox proportional hazards models.

RESULTS

During mean observation time of 2.7 ± 1.0 years, 863 (3.5%) sustained one or more major osteoporotic fractures (MOF), 212 (0.8%) sustained a hip fracture, and 1210 (4.9%) sustained any incident fracture. Compared with no falls in the previous year (referent), there was a gradient of increasing risk for fracture with increasing number of falls (all P < 0.001). Results showed minimal attenuation with covariate adjustment. When adjusted for baseline fracture probability (FRAX score with BMD) the HR for MOF increased from 1.49 (95% CI 1.25-1.78) for one fall to 1.74 (1.33-2.27) for two falls to 2.62 (2.06-3.34) for ≥ 3 falls. HRs were similar for any incident fracture and slightly greater for prediction of hip fracture, reaching 3.41 (95% CI 2.19-5.31) for ≥ 3 previous falls.

CONCLUSIONS

Self-report number of falls in the previous year is strongly associated with incident fracture risk in the routine clinical practice setting, and this risk is independent of age, sex, BMD, and baseline fracture probability. Moreover, there is dose-response with multiple falls (up to a maximum of 3) conferring greater risk than a single fall.

A population-based study of postfracture care in Manitoba, Canada 2000/2001-2014/2015

We previously found that population-based postfracture notification, which informed primary care physicians of their patient's recent fracture and suggested assessment for osteoporosis, led to an improvement in postfracture care in the context of a randomized controlled trial ( ClinicalTrials.gov identifier NCT00594789, fractures from late 2007 to mid-2010). Since June 2010, a province-wide postfracture notification program was implemented. This study was to (1) determine whether this program has resulted in sustained improvement in postfracture care and (2) test factors associated with receiving osteoporosis care.

METHODS

A retrospective matched cohort study was performed using population-based health administrative data in Manitoba, Canada. We selected individuals aged 50+ years with an incident major osteoporosis fracture (MOF; N = 18,541) in fiscal years 2000/2001 to 2013/2014 and controls without a MOF (N = 92,705) matched (5:1) on age, sex, and residential area. The Cochran-Armitage test tested for a linear trend in osteoporosis care outcomes for cases and controls. Logistic regressions were used to test characteristics associated with the likelihood of receiving osteoporosis care.

RESULTS

The percentage of individuals receiving DXA testing and/or osteoporosis medication increased in fracture cases (p < 0.001), but decreased in controls (p < 0.001). Odds ratios for osteoporosis care in years following the postfracture notification program were approximately double of those prior to the clinical trial. In addition to prior MOF (OR 9.03, 95% CI 8.60-9.48), factors associated with osteoporosis care included lower income (OR   0.72, 95% CI 0.67-0.78), glucocorticoid use (OR   4.37, 95% CI 3.72-5.14), diabetes diagnosis (OR =  0.74, 95% CI 0.68-0.80), and Charlson Comorbidity Index (indexes 1-2: OR 1.27, 95% CI 1.20-1.34; indexes 3-5: OR 1.26, 95% CI 1.13-1.40).

CONCLUSIONS

Adopting a population-based postfracture notification program led to sustained improvements in postfracture care.

Which is the preferred site for bone mineral density monitoring as an indicator of treatment-related anti-fracture effect in routine clinical practice? A registry-based cohort study

Change in total hip bone mineral density (BMD) provides a robust indication of anti-fracture effect during treatment monitoring in routine clinical practice, whereas spine BMD change is not independently associated with fracture risk.

PURPOSE

The role of monitoring bone mineral density (BMD) as an indicator of an anti-fracture effect is controversial. Discordance between the spine and hip BMD is common and creates uncertainty in clinical practice.

METHODS

Using a population-based BMD Registry for the Province of Manitoba, Canada, we compared change in the spine and hip BMD as an indicator of treatment-related fracture risk reduction. The study cohort included 6093 women age > 40 years initiating osteoporosis treatment with two consecutive dual-energy X-ray absorptiometry (DXA) scans (mean interval 4.7 years). We computed change in the spine, total hip, and femur neck BMD between the first and second DXA scans as categorical (categorized as stable, detectable decrease, or detectable increase) and continuous measures. We modeled time to first incident fracture, ascertained from health services data, using Cox regression adjusted for baseline fracture probability.

RESULTS

During a mean follow-up of 12.1 years, 995 women developed incident major osteoporotic fractures (MOF) including 246 with hip fractures and 301 with clinical vertebral fractures. Women with a detectable decrease in total hip BMD compared with stable BMD experienced an increase in MOF (adjusted hazard ratio [aHR] 1.46, 95% confidence interval [CI] 1.25-1.70) while those with a detectable increase in total hip BMD experienced a decrease in MOF (aHR 0.71, 95% CI 0.61-0.83), and these results were not attenuated when adjusted for change in spine BMD. Similar results were seen for hip and clinical vertebral fracture outcomes, when BMD change was assessed as a continuous measure, and when femur neck BMD monitoring was used instead of total hip BMD monitoring.

CONCLUSIONS

Treatment-related increases in total hip BMD are associated with lower MOF, hip, and clinical vertebral fracture risk compared with stable BMD, while BMD decreases are associated with higher fracture risk. In contrast, spine BMD change is not independently associated with fracture risk.

Administrative healthcare data applied to fracture risk assessment

Fracture risk scores generated from population-based administrative healthcare data showed comparable or better discrimination than the Fracture Risk Assessment Tool (FRAX) scores computed without bone mineral density for predicting incident major osteoporotic fracture. Administrative data may be useful to identify individuals at high fracture risk at the population level.

PURPOSE

To evaluate the discrimination of fracture risk scores defined using inputs available from administrative data for predicting incident major osteoporotic fracture (MOF) and hip fracture (HF) alone.

METHODS

Using the Manitoba Bone Mineral Density (BMD) Database (1997-2013), we identified 61,041 individuals aged 50 years or older with healthcare coverage following their first BMD test. We calculated two-modified FRAX)scores based on administrative data: FRAX-A and FRAX-A⁺. The FRAX-A modification used all FRAX inputs, except for BMD, body mass index, and parental HF, while the FRAX-A⁺ modification using all FRAX-A inputs plus a comorbidity score, number of hospitalizations in the 3 years prior to the BMD test, depression diagnosis, and dementia diagnosis. FRAX scores computed with BMD (i.e., FRAX [BMD]) and without BMD (i.e., FRAX [no-BMD]) were the comparators.

RESULTS

During a mean of 7 years of follow-up, we identified 5306 (8.7%) incident MOF and 1532 (2.5%) incident HF. The c-statistic for MOF associated with FRAX-A was lower than FRAX (BMD) (0.655 vs 0.675; P < 0.05) and comparable to FRAX (no-BMD) (0.654; P = 0.07). The c-statistic for MOF using FRAX-A⁺ (0.663) was lower than FRAX (BMD) but higher than FRAX (no-BMD) (both P < 0.05). For predicting incident HF, c-statistics associated with FRAX-A (0.762) and FRAX-A⁺ (0.767) were lower than FRAX (BMD) (0.789) and FRAX (no-BMD) (0.773; both P < 0.05).

CONCLUSIONS

FRAX-A and FRAX-A⁺ showed comparable or better discrimination than FRAX without BMD for predicting incident MOF, but slightly lower discrimination for HF alone.

Lean mass and lower limb muscle function in relation to hip strength, geometry and fracture risk indices in community-dwelling older women

In a population-based sample of British women aged over 70 years old, lean mass and peak lower limb muscle force were both independently associated with hip strength and fracture risk indices, thereby suggesting a potential benefit of promoting leg muscle strengthening exercise for the prevention of hip fractures in postmenopausal women.

INTRODUCTION

To investigate cross-sectional associations of lean mass and physical performance, including lower limb muscle function, with hip strength, geometry and fracture risk indices (FRIs) in postmenopausal women.

METHODS

Data were from the Cohort of Skeletal Health in Bristol and Avon. Total hip (TH) and femoral neck (FN) bone mineral density (BMD), hip geometry and total body lean mass (TBLM) were assessed by dual x-ray absorptiometry (DXA). Finite element analysis of hip DXA was used to derive FN, intertrochanteric and subtrochanteric FRIs. Grip strength, gait speed and chair rise time were measured objectively. Lower limb peak muscle force and muscle power were assessed by jumping mechanography.

RESULTS

In total, 241 women were included (age = 76.4; SD = 2.6 years). After adjustment for age, height, weight/fat mass and comorbidities, TBLM was positively associated with hip BMD (β_{TH BMD} = 0.36, P ≤ 0.001; β_{FN BMD} = 0.26, P = 0.01) and cross-section moment of inertia (0.24, P ≤ 0.001) and inversely associated with FN FRI (- 0.21, P = 0.03) and intertrochanteric FRI (- 0.11, P = 0.05) (estimates represent SD difference in bone measures per SD difference in TBLM). Lower limb peak muscle force was positively associated with hip BMD (β_{TH BMD} = 0.28, P ≤ 0.001; β_{FN BMD} = 0.23, P = 0.008) and inversely associated with FN FRI (- 0.17, P = 0.04) and subtrochanteric FRI (- 0.18, P = 0.04). Associations of grip strength, gait speed, chair rise time and peak muscle power with hip parameters were close to the null.

CONCLUSIONS

Lean mass and lower limb peak muscle force were associated with hip BMD and geometrical FRIs in postmenopausal women. Leg muscle strengthening exercises may therefore help prevent hip fractures in older women.

Diagnosis and management of bone fragility in diabetes: an emerging challenge

Fragility fractures are increasingly recognized as a complication of both type 1 and type 2 diabetes, with fracture risk that increases with disease duration and poor glycemic control. Yet the identification and management of fracture risk in these patients remains challenging. This review explores the clinical characteristics of bone fragility in adults with diabetes and highlights recent studies that have evaluated bone mineral density (BMD), bone microstructure and material properties, biochemical markers, and fracture prediction algorithms (i.e., FRAX) in these patients. It further reviews the impact of diabetes drugs on bone as well as the efficacy of osteoporosis treatments in this population. We finally propose an algorithm for the identification and management of diabetic patients at increased fracture risk.

In which patients does lumbar spine trabecular bone score (TBS) have the largest effect?

BACKGROUND

Lumbar spine TBS, a texture index derived from lumbar spine dual-energy x-ray absorptiometry (DXA) images, enhances fracture prediction. No studies to date have studied a broad range of clinical variables to determine which patients might experience the greatest benefit from the use of TBS.

METHODS

Using the Manitoba BMD Registry, we identified 37,176 subjects with baseline DXA, FRAX®-based fracture probability, lumbar spine TBS, and minimum 5 years of observation. Subgroups considered were based on sex, age, body mass index (BMI), prior fracture, chronic obstructive lung disease (COPD), high alcohol use, rheumatoid arthritis (RA), high glucocorticoid use, osteoporotic femoral neck T-score, number of comorbidities, diabetes, secondary osteoporosis, and prior osteoporosis treatment. Non-traumatic major osteoporotic fractures (MOF, n = 3741) and hip fractures (HF, n = 1008) were identified using population-based health services data. We analyzed baseline TBS using analysis of covariance (ANCOVA). FRAX-adjusted hazard ratios (HR) per SD reduction in TBS were estimated and tested for interactions. Categorical net reclassification improvement (NRI) was estimated using fixed FRAX-based intervention cut-offs.

RESULTS

Adjusted baseline TBS was significantly lower (p ≤ 0.001) for women (-4.2%), osteoporotic hip T-score (-4.0%), COPD (-2.8%), diabetes (-2.6%), high alcohol use (-2.3%), prior fracture (-2.2%), glucocorticoid use (-1.5%), RA (-0.9%) and secondary osteoporosis (-0.8%), whereas recent osteoporosis therapy was associated with greater TBS (+1.5%). HRs per SD reduction in TBS for fracture prediction were larger for age < 65 vs 65+ (MOF p-interaction = 0.004, HF p-interaction < 0.001), without vs with prior fracture (MOF p-interaction = 0.003, HF p-interaction = 0.048), without vs with glucocorticoid use (HF p-interaction = 0.029), lower vs higher comorbidity score (HF p-interaction < 0.001), and without vs with osteoporosis treatment (MOF p-interaction = 0.005). NRI for using the TBS adjustment to FRAX in all subjects was 1.2% for MOF (p = 0.002) and 1.7% for HF (p = 0.016). NRI was greater in subjects age < 65 y (MOF:1.7%, HF:5.6%), no prior fracture (HF: 2.4%), non-osteoporotic T-score (HF: 3.0%), and high glucocorticoid use (MOF: 3.9%).

CONCLUSION

TBS is sensitive to the effects of multiple risk factors for fracture. TBS-adjusted fracture risk assessment resulted in significant improvements for multiple subgroups.

Risk-equivalent T-score adjustment for using lumbar spine trabecular bone score (TBS): the Manitoba BMD registry

Lumbar spine trabecular bone score (TBS) can be used to modify the output from the fracture risk assessment tool, FRAX, to enhance fracture prediction. An alternative approach for using TBS in clinical practice, based upon an adjustment to the bone mineral density (BMD) T-score, may be helpful in regions where intervention guidelines and/or reimbursement are primarily based on BMD T-score.

INTRODUCTION

The aim of this study is to develop an approach for using TBS in clinical practice based upon a "risk-equivalent" adjustment to the BMD T-score.

METHODS

We identified 45,185 women age 40 years and older with baseline spine and hip DXA, TBS, and FRAX probabilities including femoral neck BMD. Incident major osteoporotic fractures (MOF, n = 3925) were identified from population-based health services data (mean follow-up 7.4 years comprising 335,910 person-years). Cox proportional hazards models adjusted for age and BMI were first used to estimate the risk for MOF from BMD T-score alone, then after including TBS and a multiplicative age interaction term. From the parameter estimates, we developed a TBS offset to the BMD T-score based upon change in TBS that would give the same risk as a unit change in BMD T-score for the femoral neck, total hip, and lumbar spine.

RESULTS

All BMD measurements, TBS, and the age interaction term independently predicted MOF (p < 0.001). Measures of risk stratification and model fit were improved for the TBS-adjusted BMD T-score versus the unadjusted BMD T-score (p < 0.001). There was a high level of agreement between MOF probability estimated from TBS-adjusted MOF FRAX probability and FRAX probability using the "risk-equivalent" femoral BMD T-score: MOF probability r² = 0.98, slope = 1.02, intercept = - 0.3; hip probability r² = 0.95, slope = 1.07, intercept = 0.0.

CONCLUSIONS

The BMD-independent effect of lumbar spine TBS on fracture risk can be estimated as a simple offset to the BMD T-score.

Performance of FRAX in clinical practice according to sex and osteoporosis definitions: the Manitoba BMD registry

Among 62,275 women and 6455 men, FRAX stratified risk for incident major osteoporotic fracture (MOF) and incident hip fracture (HF) without sex interaction. Performance was good in those with osteoporosis regardless of how this was defined.

INTRODUCTION

Some studies have reported that FRAX performance differs according to sex and/or osteoporosis definitions. We evaluated whether the performance of FRAX to predict incident MOF and HF in women and men was affected by the presence or absence of osteoporosis defined by World Health Organization (WHO) or National Osteoporosis Foundation (NOF) criteria.

METHODS

We studied women and men age ≥ 40 years with baseline hip and spine DXA scans (1996-2013). Individuals were classified into four non-overlapping subgroups: osteoporosis by WHO criteria, osteoporosis exclusively by NOF criteria, high fracture risk by FRAX (MOF ≥ 20% or HF ≥ 3%, without osteoporosis), and low fracture risk (MOF < 20% and HF < 3% without osteoporosis). In each subgroup, we evaluated stratification (hazard ratios [HR]) and calibration (observed vs predicted 10-year fracture probability) for incident fracture.

RESULTS

The population included 62,275 women (5345 MOF and 1471 HF) and 6455 men (405 MOF and 108 HF). FRAX scores were strongly predictive of MOF (HR per SD: women 2.12, 95% CI 2.06-2.18; men 1.89, 95% CI 1.73-2.08; sex interaction p value = 0.97) and HF (women 4.78, 95% CI 4.44-5.14; men 4.20, 95% CI 3.22-5.49; sex interaction p value = 0.71). FRAX scores gave similar HRs for MOF among the four subgroups (subgroup interaction p value 0.34 for women, 0.22 for men). Observed versus predicted 10-year MOF and HF probability for the defined subgroups demonstrated a high level of concordance for women and men (all r² ≥ 0.9).

CONCLUSIONS

FRAX was a strong and consistent predictor of MOF and HF in both women and men and performed well in those with osteoporosis whether defined by WHO or NOF criteria.

Automated DXA-based finite element analysis for hip fracture risk stratification: a cross-sectional study

Fracture risk indices (FRIs) generated from DXA-based finite element analysis were associated with hip fracture independent of FRAX score computed with femoral neck bone mineral density (BMD). Prospective studies are warranted to determine whether FRIs represent an improvement over BMD for predicting incident hip fractures.

INTRODUCTION

The study aims to examine the association between prior hip fracture and FRIs derived from automated finite element analysis (FEA) of DXA hip scans. Femoral neck, intertrochanteric, and subtrochanteric FRIs were calculated as the von Mises stress induced by a sideways fall divided by the bone yield stress over the specified region of interest (ROI).

METHODS

Using the Manitoba Bone Mineral Density Database, we selected women age ≥ 65 years with femoral neck T-scores below - 1 and no osteoporosis treatment. From this population, we identified 324 older women with hip fracture before DXA testing and a random sample of 658 non-fracture controls. FRIs were derived from the anonymized DXA scans. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) for the associations between FRIs (per SD increase) and hip fracture.

RESULTS

After adjusting for FRAX score (hip fracture with BMD), femoral neck FRI (OR 1.36, 95% CI 1.13, 1.64), intertrochanteric FRI (OR 1.81, 95% CI 1.44, 2.27), and subtrochanteric FRI (OR 2.09, 95% CI 1.68, 2.60) were associated with hip fracture. Intertrochanteric and subtrochanteric FRIs gave significantly higher c-statistics (all P ≤ 0.05) than femoral neck BMD. Subgroup analyses showed that all FRIs were more strongly associated with hip fracture in women who were younger and had higher body mass index (BMI) or non-osteoporotic BMD (all P _interaction < 0.1).

CONCLUSIONS

FRIs derived from DXA-based FEA were independently associated with prior hip fracture, suggesting that they could potentially improve hip fracture risk assessment.

Effects of obesity and diabetes on rate of bone density loss

In this large registry-based study, women with diabetes had marginally greater bone mineral density (BMD) loss at the femoral neck but not at other measurement sites, whereas obesity was not associated with greater BMD loss. Our data do not support the hypothesis that rapid BMD loss explains the increased fracture risk associated with type 2 diabetes and obesity observed in prior studies.

INTRODUCTION

Type 2 diabetes and obesity are associated with higher bone mineral density (BMD) which may be less protective against fracture than previously assumed. Inconsistent data suggest that rapid BMD loss may be a contributing factor.

METHODS

We examined the rate of BMD loss in women with diabetes and/or obesity in a population-based BMD registry for Manitoba, Canada. We identified 4960 women aged ≥ 40 years undergoing baseline and follow-up BMD assessments (mean interval 4.3 years) without confounding medication use or large weight fluctuation. We calculated annualized rate of BMD change for the lumbar spine, total hip, and femoral neck in relation to diagnosed diabetes and body mass index (BMI) category.

RESULTS

Baseline age-adjusted BMD was greater in women with diabetes and for increasing BMI category (all P < 0.001). In women with diabetes, unadjusted BMD loss was less at the lumbar spine (P = 0.017), non-significantly greater at the femoral neck (P = 0.085), and similar at the total hip (P = 0.488). When adjusted for age and BMI, diabetes was associated with slightly greater femoral neck BMD loss (- 0.0018 g/cm²/year, P = 0.012) but not at the lumbar spine or total hip. There was a strong linear effect of increasing BMI on attenuated BMI loss at the lumbar spine with negligible effects on hip BMD.

CONCLUSIONS

Diabetes was associated with slightly greater BMD loss at the femoral neck but not at other measurement sites. BMD loss at the lumbar spine was reduced in overweight and obese women but BMI did not significantly affect hip BMD loss.

Clinical performance of an updated trabecular bone score (TBS) algorithm in men and women: the Manitoba BMD cohort

This is the first study to directly compare the original and recently updated versions of the trabecular bone score (TBS) algorithm. We confirmed improved performance of the new algorithm, especially among men.

INTRODUCTION

Lumbar spine trabecular bone score (TBS) predicts major osteoporotic fractures (MOFs) and hip fractures (HFs) independent of bone density. The original TBS algorithm (version 1; [TBS-v1]) was optimized for women of average body size. Limitations were identified when used in men or extremes of body mass index (BMI). The current study evaluates an updated TBS algorithm (version 2; [TBS-v2]) modified to address these issues.

METHODS

From a registry with all DXA results for Manitoba, Canada, we identified 47,736 women and 4348 men age ≥ 40 with baseline spine DXA (GE Prodigy, 1999-2011). Spine TBS was measured using both TBS-v1 and TBS-v2 algorithms. Risk stratification for incident fractures identified from population-based data was assessed from area under the receiver operating characteristic curve (AUROC).

RESULTS

With the TBS-v1 algorithm, average TBS for men was significantly lower than for women (p < 0.001) and showed significant inverse correlations with BMI (Pearson r-0.40 in men, -0.18 in women [both p < 0.001]). With the TBS-v2 algorithm, average values for men were slightly greater than for women (p < 0.001) and there were no significant correlations with BMI (Pearson r 0.01 in men, -0.01 in women [both p > 0.1]). During mean follow-up of 5 years in men, there were 214 incident MOFs and 47 HFs; during 6 years mean follow-up in women, there were 2895 incident MOFs and 694 HFs. Improvements in fracture prediction were seen with TBS-v2 in both men (change in AUROC for MOFs +0.021 [p = 0.17], HFs +0.046 [p = 0.04]) and women (change in AUROC for MOFs +0.012 [p < 0.001], HFs +0.020 [p < 0.001]).

CONCLUSION

The updated TBS algorithm is less affected by BMI, gives higher mean results for men than women consistent with their lower fracture risk, and improves fracture prediction in both men and women.

Trabecular bone score (TBS): Method and applications

Trabecular bone score (TBS) is a texture index derived from standard lumbar spine dual energy X-ray absorptiometry (DXA) images and provides information about the underlying bone independent of the bone mineral density (BMD). Several salient observations have emerged. Numerous studies have examined the relationship between TBS and fracture risk and have shown that lower TBS values are associated with increased risk for major osteoporotic fracture in postmenopausal women and older men, with this result being independent of BMD values and other clinical risk factors. Therefore, despite being derived from standard DXA images, the information contained in TBS is independent and complementary to the information provided by BMD and the FRAX® tool. A procedure to generate TBS-adjusted FRAX probabilities has become available with the resultant predicted fracture risks shown to be more accurate than the standard FRAX tool. With these developments, TBS has emerged as a clinical tool for improved fracture risk prediction and guiding decisions regarding treatment initiation, particularly for patients with FRAX probabilities around an intervention threshold. In this article, we review the development, validation, clinical application, and limitations of TBS.

FRAX for fracture prediction shorter and longer than 10 years: the Manitoba BMD registry

In a large clinical registry for the province of Manitoba, Canada, FRAX predicted incident MOF and hip fracture from 1 to 15 years following baseline assessment. A simple linear rescaling of FRAX outputs seems useful for predicting both short- and long-term fracture risk in this population.

INTRODUCTION

FRAX® estimates 10-year probability of major osteoporotic fracture (MOF) and hip fracture. We examined FRAX predictions over intervals shorter and longer than 10 years.

METHODS

Using a population-based clinical registry for Manitoba, Canada, we identified 62,275 women and 6455 men 40 years and older with baseline dual-energy X-ray absorptiometry scans and FRAX scores. Incident MOF and hip fracture were assessed up to 15 years from population-based data. We assessed agreement between estimated fracture probability from 1 to 15 years using linearly rescaled FRAX scores and observed cumulative fracture probability. The gradient of risk for FRAX probability and incident fracture was examined overall and for 5-year intervals.

RESULTS

FRAX predicted incident MOF and hip fracture for all time intervals. There was no attenuation in the gradient of risk for MOF even for years >10. Gradient of risk was slightly lower for hip fracture prediction in years >10 vs years <5, though HRs remained high. Linear agreement was seen in the relationships between observed vs predicted (rescaled) FRAX probabilities (R ² 0.95-1.00). Among women, there was near-perfect linearity in MOF predictions. Deviations from linearity, with a slightly higher observed than predicted MOF probability, were most evident in the first years following a fracture event and after 10 years for hip fracture prediction in women using FRAX with BMD. Simulations showed that results were robust to large differences in fracture rates and moderate differences in mortality rates.

CONCLUSIONS

FRAX predicts incident MOF and hip fracture up to 15 years and could be adapted to predict fracture over time periods shorter and longer term than 10 years in populations with fracture and mortality epidemiology similar to Canada.

The association between sclerostin and incident type 2 diabetes risk: a cohort study

OBJECTIVE

To determine whether sclerostin is associated with fasting glucose, insulin levels, insulin resistance or increased risk of incident type 2 diabetes.

BACKGROUND

Type 2 diabetic patients have a higher risk of fractures. Recent studies suggest sclerostin, a regulator of osteoblast activity, is associated with diabetes.

MATERIALS AND METHODS

Sclerostin levels were obtained from 1778 individuals with no history of type 2 diabetes participating in the population-based Canadian Multicentre Osteoporosis Study (CaMos) cohort. Participants were followed until diagnosis of type 2 diabetes, death or end of the study period (31 December 2013). The relationship of sclerostin with fasting glucose, insulin levels and homoeostatic model assessment-insulin resistance (HOMA-IR) was studied in linear regression models. Cox proportional hazards models were used to determine the association of sclerostin levels and the risk of incident type 2 diabetes during a mean 7·5 years of follow-up.

RESULTS

Fasting glucose, fasting insulin levels and HOMA-IR were weakly correlated with sclerostin levels (Spearman's correlation coefficient: 0·11, P < 0·05; -0·09, P < 0·05; and -0·07, P = 0·02, respectively). Multiple linear regression analyses confirmed a significant association between sclerostin and fasting insulin and HOMA-IR but no significant association with fasting glucose levels. Sclerostin levels were not found to be significantly associated with the risk of incident type 2 diabetes (HR: 1·30; 95% CI: 0·37-4·57).

CONCLUSIONS

We observed an association between sclerostin levels with fasting insulin levels and HOMA-IR, but there was no clear association with type 2 diabetes risk. Further studies are needed to understand the role of sclerostin in type 2 diabetes.

The FRAX-based Lebanese osteoporosis treatment guidelines: rationale for a hybrid model

We describe our approach to develop FRAX-based osteoporosis treatment guidelines in Lebanon, a country with low-moderate fracture rates. A hybrid assessment algorithm that combines a fixed 10 % intervention threshold until age 70 years, and an age-dependent threshold thereafter, was deemed most suitable.

INTRODUCTION

The FRAX risk calculator is used to guide intervention thresholds in several national osteoporosis guidelines. This study aimed to describe the approach in developing FRAX-based osteoporosis treatment guidelines in Lebanon, a country with relatively low fracture rates.

METHODS

We reassessed previous national guidelines combined with an evaluation of age-dependent and fixed FRAX-based intervention threshold models used in the UK, the USA, and Canada. We took into consideration the risk for major osteoporotic fractures (MOF) and the proportions of subjects considered for therapy using such thresholds, before finalizing a model for Lebanon.

RESULTS

The new Lebanese guidelines retained the recommendation to treat individuals with fragility fracture at the hip or spine. A femoral neck T-score ≤-2.5 in subjects without fractures was dropped, since it would imply consideration of therapy for individuals with a 10-year risk for MOF of <10 %, up to age 75 years in women. After considering the impact of both age-dependent and fixed intervention thresholds, we chose a new hybrid algorithm, combining a fixed 10 % treatment threshold until age 70 years and an age-dependent threshold thereafter.

CONCLUSION

The Lebanese FRAX-based hybrid model takes into consideration the risk for MOF and the proportions of subjects considered for treatment. This model avoids consideration of drug therapy in a large proportion of younger subjects at low risk for fracture and targets high risk elderly individuals. It was deemed most suitable for Lebanon and may be an option for other countries with relatively low fracture rates.

The current economic burden of illness of osteoporosis in Canada

We estimate the current burden of illness of osteoporosis in Canada is double ($4.6 billion) our previous estimates ($2.3 billion) due to improved data capture of the multiple encounters and services that accompany a fracture: emergency room, admissions to acute and step-down non-acute institutions, rehabilitation, home-assisted or long-term residency support.

INTRODUCTION

We previously estimated the economic burden of illness of osteoporosis-attributable fractures in Canada for the year 2008 to be $2.3 billion in the base case and as much as $3.9 billion. The aim of this study is to update the estimate of the economic burden of illness for osteoporosis-attributable fractures for Canada based on newly available home care and long-term care (LTC) data.

METHODS

Multiple national databases were used for the fiscal-year ending March 31, 2011 (FY 2010/2011) for acute institutional care, emergency visits, day surgery, secondary admissions for rehabilitation, and complex continuing care, as well as national dispensing data for osteoporosis medications. Gaps in national data were supplemented by provincial and community survey data. Osteoporosis-attributable fractures for Canadians age 50+ were identified by ICD-10-CA codes. Costs were expressed in 2014 dollars.

RESULTS

In FY 2010/2011, the number of osteoporosis-attributable fractures was 131,443 resulting in 64,884 acute care admissions and 983,074 acute hospital days. Acute care costs were $1.5 billion, an 18 % increase since 2008. The cost of LTC was 33.4 times the previous estimate ($31 million versus $1.03 billion) because of improved data capture. The cost for rehabilitation and secondary admissions increased 3.4 fold, while drug costs decreased 19 %. The overall cost of osteoporosis was over $4.6 billion, an increase of 83 % from the 2008 estimate.

CONCLUSION

Since the 2008 estimate, new Canadian data on home care and LTC are available which provided a better estimate of the burden of osteoporosis in Canada. This suggests that our previous estimates were seriously underestimated.

Antiresorptive therapy and newly diagnosed diabetes in women: a historical cohort study

AIMS

Undercarboxylated osteocalcin (ucOC) promotes increased insulin sensitivity and increased secretion. Since antiresorptive therapy (AT) decreases ucOC levels, AT could increase the risk of diabetes and this would have serious clinical ramifications. We sought to test this hypothesis by examining the association between new use of AT and newly-diagnosed diabetes.

METHODS

Using a bone mineral density (BMD) registry for Manitoba, Canada, we identified 33 640 women aged ≥50 years without diabetes at their first BMD test for 1998-2013. We linked these women to a province-wide retail pharmacy database to identify new AT exposure each year for up to 5 years after a BMD test. Time-dependent analysis was used to test the independent association between new use of AT and newly diagnosed diabetes.

RESULTS

This cohort had a mean age of 65 years, a mean body mass index of 26.8 kg/m(2) , and 12% were receiving glucocorticoid and 13% hormone replacement therapy at BMD test. In the first year after BMD test, 29% of women started AT (bisphosphonates, 92%). Over a mean 4.2 years of follow-up, 3.7% new AT users and 4.2% non-users had diabetes (adjusted hazard ratio 1.01, 95% confidence interval 0.87-1.16). Sensitivity analyses using AT dose-response gradients also found no significant associations with diabetes.

CONCLUSIONS

Despite the plausible biological mechanisms related to ucOC, new use of AT was not a risk factor for diabetes in this cohort. The clinical implications of these findings are reassuring, as AT is widely prescribed for treating osteoporosis in older women who are also at high risk of developing diabetes.

Direct comparison of FRAX(R) and a simplified fracture risk assessment tool in routine clinical practice: a registry-based cohort study

FRAX(R) incrementally improved prediction of incident major osteoporotic fractures compared with the simplified Canadian Association of Radiologists and Osteoporosis Canada (CAROC) tool.

INTRODUCTION

There is debate over the value of seemingly more complex fracture prediction tools over simpler fracture prediction tools. FRAX(R) and the simplified CAROC tool are both widely used in Canada for estimating 10-year probability of major osteoporotic fractures. We compared the performance of these tools for predicting fracture outcomes.

METHODS

Using a bone densitometry registry for Manitoba, Canada, we identified 34,060 individuals age ≥50 years not receiving anti-osteoporosis therapy. Fracture Risk Assessment (FRAX) and CAROC were used to classify 10-year fracture risk as low (<10 %), moderate (10-20 %) and high (>20 %). Net reclassification improvement (NRI) was used to quantify the performance of FRAX versus CAROC.

RESULTS

During mean 9.8 years of follow-up, 3905 individuals sustained fractures. There were 10 (of 35 total) situations where observed fracture risk fell outside of the predicted range, and all 10 discordances favoured FRAX. NRI among incident fracture cases was not significantly changed, but there was a significant improvement in risk categorization for those who remained fracture-free (+1.7 %, P < 0.001) resulting in overall improvement (NRI overall +0.028, P < 0.001). Within nine pre-specified subgroups, there was no case of significant worsening in NRI when using FRAX instead of CAROC. In absolute terms, only 36 individuals would need to be assessed using FRAX instead of CAROC to yield an improvement in prediction (8 among individuals with prior fracture and 4 among those with prolonged glucocorticoid use).

CONCLUSIONS

FRAX provides improvement in fracture risk prediction compared with the simplified CAROC tool in individuals referred for osteoporosis screening, supporting the use of FRAX as the international reference tool for fracture risk assessment.