A comparison of bone density and bone morphology between patients presenting with hip fractures, spinal fractures or a combination of the two

Risk of fracture among patients with spinal cord injury: A nationwide cohort study in South Korea

BACKGROUND

Clinical concerns about preventing and managing fractures after spinal cord injury (SCI) have been growing.

OBJECTIVE

This study investigates the risk of fractures among SCI patients according to the presence of disability, disease severity, and level of injury.

METHODS

We performed a retrospective cohort study using the Korean National Health Insurance Service (KNHIS 2010-2018) database. We included 5190 SCI patients and 1:3 age- and sex-matched control participants. The primary outcome was fracture, and the cohort was followed until December 31, 2019.

RESULTS

SCI patients had a higher fracture risk than the matched controls (adjusted hazard ratio [aHR] 1.33, 95 % CI 1.16-1.54). The risk of fracture was higher in the presence of disability (aHR 1.57, 95 % CI 1.19-2.07), especially among patients with severe disability (aHR 1.65, 95 % CI 1.05-2.60). Higher fracture risks were observed among SCI patients regardless of injury level, but statistical significance was found only with cervical-level injury. When we considered site-specific fractures, vertebral (aHR 1.31, 95 % CI 1.04-1.64) and hip fracture risks (aHR 2.04, 95 % CI 1.39-2.98) were both higher among SCI patients than the controls. SCI patients with disability and cervical-level injury showed the highest hip fracture risk (aHR 3.67, 95 % CI 1.90-7.07).

CONCLUSIONS

Compared with the controls, SCI patients were at higher risk of any fracture, particularly hip fracture, especially those with disability and cervical-level injury. Clinicians should be aware of the fracture risk among SCI patients to provide proper management.

Polymorphisms in the Runx2 and osteocalcin genes affect BMD in postmenopausal women: a systematic review and meta-analysis

PURPOSE

Runx2 and osteocalcin have pivotal roles in bone homeostasis. Polymorphism of these two genes could alter the function of osteoblasts and consequently bone mineral density (BMD). Attempts to understand the relationship between these polymorphisms and BMD in postmenopausal women across a variety of populations have yielded inconsistent results. This meta-analysis seeks to define the relationship between these polymorphisms with BMD in postmenopausal women.

METHODS

Eligible studies were identified from three electronic databases. Data were extracted from the eligible studies (4 studies on Runx2 and 6 studies on osteocalcin), and associations of Runx2 T > C and osteocalcin HindIII polymorphisms with BMD in postmenopausal women were assessed using standard difference in means (SDM) and 95% confidence intervals (CI) as statistical measures.

RESULTS

A significant difference in the lumbar spine (LS) BMD in postmenopausal women was observed between the TT and CC homozygotes for the Runx2 T > C (SDM = -0.445, p-value = 0.034). The mutant genotypes (CC) showed significantly lower LS BMD in comparison to wild type genotypes under recessive model of genetic analysis (TC + TT vs. CC: SDM = -0.451, p-value = 0.032). For osteocalcin, HindIII polymorphism, the mutant genotypes (HH) was associated with significantly higher BMD for both LS and femoral neck (FN) than the wild type (hh) homozygotes (SDM = 0.152, p-value = 0.008 and SDM = 0.139, p-value = 0.016 for LS and FN, respectively). There was no association between total hip (TH) BMD and the osteocalcin HindIII polymorphism.

CONCLUSIONS

Runx2 T > C and osteocalcin HindIII polymorphisms influence the level of BMD in postmenopausal women and may be used as predictive markers of osteoporosis.

Effect of Zoledronic Acid in Hepatic Osteodystrophy: A Double-Blinded Placebo-Controlled Trial

Purpose

Literature on the treatment of pre-transplant hepatic osteodystrophy (HOD) is limited. The general treatment measures and their timing are currently adopted from the literature on postmenopausal osteoporosis. Therefore, we conducted this randomized study to investigate the effect of zoledronic acid (ZA) on HOD.

Methods

We randomized 36 male patients with cirrhosis (Child-Pugh class A and B) into 19 to the ZA arm and 17 to the placebo arm, respectively. Patients in the ZA arm received a single infusion of 4 mg ZA dissolved in 100 mL of normal saline at baseline, while patients in the placebo arm received a similar infusion of normal saline at baseline. The primary outcome of the study was the change in lumbar spine bone mineral density (LS-BMD) at 12 months.

Results

Of 36 patients, 28 completed the study (15 in the ZA arm and 13 in the placebo arm). The mean increase in LS-BMD (g/cm2) in the ZA and placebo arms was 5.11% (3.50) and 0.72% (4.63) [P = 0.008], respectively. The trabecular bone score (TBS) did not improve significantly in either arm. The incidence of vertebral fractures (VFs) was similar in both arms. There was a significant decrease in plasma beta-C-terminal telopeptide (β-CTX) levels in the ZA arm compared to the placebo arm, while the change in plasma levels of procollagen 1 intact N-terminal propeptide (P1NP) was similar in both arms. Six patients (31.6%) in the ZA arm experienced adverse reactions such as fever and myalgia.

Conclusion

ZA improved LS-BMD in male patients with HOD by decreasing bone resorption. However, it may not improve trabecular microarchitecture or prevent morphometric VFs in this population.

Regional variations in the intra- and intervertebral trabecular microarchitecture of the osteoporotic axial skeleton

Trabecular structures in vertebral bodies are unequally distributed in the cervical, thoracic and lumbar spine, and also within individual vertebrae. Knowledge of the microstructure of these entities could influence our comprehension and treatment of osteoporotic fractures, and even surgical procedures. Appropriate investigations may clarify the pathomechanisms of various osteoporotic fractures (fish, wedge-shaped, and flat vertebrae). We obtained three cancellous bone cylinders from the centers and margins of cervical vertebra 3 to lumbar vertebra 5, and investigated these in regard of bone volume fraction, trabecular thickness, separation, trabecular number, trabecular bone pattern factor, connectivity density, and degree of anisotropy. Using a Jamshidi needle^®, we obtained samples from three quadrants (QI: right-sided edge, QII: central, QIII: left-sided edge) of 242 prepared vertebrae, and investigated these on a micro-CT device. In all, 726 bone samples were taken from eleven body donors. Bone volume fraction, trabecular thickness, and the degree of anisotropy were significantly lower in QII than in QI and QIII. Trabecular pattern factor, however, was significantly higher in QII than in QI and QIII. The results helped to explain fish vertebrae. Wedge fractures and flat vertebrae are most likely caused by the complex destruction of trabecular and cortical structures. The higher bone volume fraction in the cervical spine compared to the thoracic and lumbar spine accounts for the small number of fractures in the cervical spine. The marked trabecular pattern factor in the center of thoracic and lumbar vertebrae could be a reason for the surgeon to use different screw designs for individual vertebrae.

Histomorphometric analysis of osteocyte density and trabecular structure of 92 vertebral bodies of different ages and genders

BACKGROUND

Knowledge of the histomorphometric structure of the vertebral body and factors influencing the structure is essential for a fundamental understanding of osteoporosis and osteoporotic fractures. The present study is focused on osteocyte density - a parameter seldom investigated so far - and trabecular width as well as bone area over tissue area in human vertebral bodies.

METHODS

Ninety-two vertebral body specimens (C5, C6, Th8, Th12, L1, L2) from 12 males and seven females were studied (Ethics Application Number A 2017-0072). The prepared vertebral specimens were extracted from the ventral aspect with a Jamshidi needle®. The punches were decalcified and subsequently H&E stained. Using the Fiji/Image J program (version 1.53 f, Wayne Resband, National Institute of Mental Health, USA), osteocyte numbers were counted per calcified bone surface, and the trabecular width and bone area of trabecular bone were measured. The collected data were analyzed using the statistical software package SPSS, version 23.0 (SPSS Inc., Chicago, USA). Pearson's correlation coefficient was used for correlation analyses. Multiple linear regression analyses were also performed.

RESULTS

Osteocyte density did not differ significantly in comparisons based on gender and age (≤65 years; ≥66 years). Men had wider trabeculae (p < 0.001) and a higher bone area over tissue area (BA/TA, %) (p = 0.025) than women. Individuals over 65 years of age had thinner trabeculae (p < 0.001) and a smaller BA/TA (%) (p < 0.001) than younger individuals. Multiple linear regression analyses were performed to determine the influence of 'gender' and 'age' on trabecular width and bone area over tissue area. The R² was 0.388 for trabecular width and 0.227 for BA/TA (%). Per year of life, trabecular width decreases by 0.368 µm (β < 0.001) and BA/TA (%) by 0.001% (β = 0.001). Men have on average 8.2 µm wider trabeculae than women (β = 0.035). A negative correlation (r = -0.275) was observed between trabecular width and osteocyte density. The wider the trabeculae, the fewer osteocytes per mm² (p = 0.008).

CONCLUSIONS

Surprisingly, we found no difference in osteocyte density with reference to age or gender. However, we did register significant age- and gender-related differences in bone area over tissue area and trabecular thickness. The age-related differences were more pronounced, implying that age-dependent loss of bone structure may be more important than differences between genders.

Why Insufficiency Fractures are Rarely Found in the Cervical Spine, Even with Osteoporosis

INTRODUCTION

The human bone structure changes with an increase in age. Both material and structural properties affect bone strength. Despite the ageing of society, however, hardly any data are available on these parameters for elderly individuals. Therefore, in the present study, cancellous bone cylinders were taken from the center of each vertebral body (C3 to L5) and examined with regard to bone volume fraction, trabecular thickness, separation, number of trabeculae, cross-linking, connectivity density and degree of anisotropy.

MATERIAL AND METHODS

Samples were obtained from 440 body donors using a Jamshidi needle and analysed using microcomputed tomography. Existing deformities, fractures and bone mineral density of each vertebra were recorded by quantitative computed tomography.

RESULTS

With regard to the microcomputed tomography parameters, statistically significant differences were found between the different sections of the vertebrae: the trabeculae of the cervical vertebrae were significantly thicker and more closely spaced than in the thoracic and lumbar vertebrae. The bone volume fraction was significantly higher in this spinal segment, as was the connection density and the number of trabeculae and cross-links. In addition, the degree of anisotropy was significantly lower in the cervical vertebrae than in the other spinal segments. With regard to quantitative computed tomography, there was a significantly higher bone mineral density in the cervical vertebrae.

CONCLUSION

Even with osteoporosis, cervical vertebrae fracture significantly later than thoracic and lumbar vertebrae due to their unique microarchitecture and higher density. Thus, the cervical vertebrae has specific properties.

Insuffizienzfrakturen der Wirbelsäule in Abhängigkeit von der spongiösen Knochendichte

Hintergrund

Das Risiko für osteoporotische Insuffizienzfrakturen (Fx) am Achsenskelett steigt mit zunehmender Abnahme der Knochendichte, wobei sich thorakal und thorakolumbal eine Häufung findet. Um die unterschiedliche Verteilung von Fx entlang der Wirbelsäule (WS) besser zu verstehen, wurden morphologische und osteodensitometrische Untersuchungen mittels Computertomographie (CT) in den verschiedenen WS-Abschnitten durchgeführt. Zudem war zu klären, ob die bei CT-Untersuchungen aus anderen Indikationen gefunden Hounsfield-Einheiten (HE) mit der Knochendichte korrelieren und Anlass für eine osteologische Diagnostik sein könnten.

Material und Methoden

Von 26 Körperspenden wurden die gesamten WS in einem Plexiglas-Wasser-Phantom fixiert und mittels hochauflösende Spiral-CT analysiert. Zusätzlich erfolgte die Messung der CT-morphologischen Spongiosadichte in HE von C3 bis S2 (624 Wirbelkörper). Der Knochenmineralgehalt (KMG, mg/ml) wurde ermittelt und zur Abschätzung einer Osteoporose (OPO) herangezogen.

Ergebnisse

Bei allen WS lag eine OPO vor. Bei einem KMG unterhalb von 60 mg/ml fanden sich signifikant vermehrte Sinterungsfrakturen im thorakalen und thorakolumbalen Bereich. Osteoporotische Insuffizienzfrakturen im HWS-Bereich fanden sich insgesamt nicht. Die Spongiosadichte war signifikant höher in den zervikalen (Median 188,6 HE) als in den lumbalen (Median 63,6 HE) und sakralen (Median 25,5 HE) Wirbelkörpern aller untersuchten WS.

Schlussfolgerung

Ein KMG-Verlust der Wirbelkörperspongiosa führt zu einem erhöhten Fx-Risiko, welches sich auch bei den verwendeten WS findet. Jedoch wird im zervikalen Bereich ein scheinbarer Schwellenwert für das Auftreten von Sinterungsfrakturen nicht unterschritten. Einen Schwellenwert für HE zu finden, wäre für die klinische Praxis relevant.

Breaking strength and bone microarchitecture in osteoporosis: a biomechanical approximation based on load tests in 104 human vertebrae from the cervical, thoracic, and lumbar spines of 13 body donors

Background

The purpose of the study was to investigate associations between biomechanical resilience (failure load, failure strength) and the microarchitecture of cancellous bone in the vertebrae of human cadavers with low bone density with or without vertebral fractures (VFx).

Methods

Spines were removed from 13 body donors (approval no. A 2017-0072) and analyzed in regard to bone mineral density (BMD), Hounsfield units (HU), and fracture count (Fx) with the aid of high-resolution CT images. This was followed by the puncture of cancellous bone in the vertebral bodies of C2 to L5 using a Jamshidi™ needle. The following parameters were determined on the micro-CT images: bone volume fraction (BVF), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), degree of anisotropy (DA), trabecular number (Tb.N), trabecular pattern factor (Tb.Pf), and connectivity density (Conn.D). The axial load behavior of 104 vertebral specimens (C5, C6, T7, T8, T9, T12, L1, L3) was investigated with a servohydraulic testing machine.

Results

Individuals with more than 2 fractures had a significantly lower trabecular pattern factor (Tb.Pf), which also proved to be an important factor for a reduced failure load in the regression analysis with differences between the parts of the spine. The failure load (FL) and endplate sizes of normal vertebrae increased with progression in the craniocaudal direction, while the HU was reduced. Failure strength (FS) was significantly greater in the cervical spine than in the thoracic or lumbar spine (p < 0.001), independent of sex. BVF, Tb.Th, Tb.N, and Conn.D were significantly higher in the cervical spine than in the other spinal segments. In contrast, Tb.Sp and Tb.Pf were lowest in the cervical spine. BVF was correlated with FL (r = 0.600, p = 0.030) and FS (r = 0.763, p = 0.002). Microarchitectural changes were also detectable in the cervical spine at lower densities.

Conclusions

Due to the unique microarchitecture of the cervical vertebrae, fractures occur much later in this region than they do in the thoracic or lumbar spine.

Trial registration

Approval no. A 2017-0072.

Using multivariable Mendelian randomization to estimate the causal effect of bone mineral density on osteoarthritis risk, independently of body mass index

OBJECTIVES

Observational analyses suggest that high bone mineral density (BMD) is a risk factor for osteoarthritis (OA); it is unclear whether this represents a causal effect or shared aetiology and whether these relationships are body mass index (BMI)-independent. We performed bidirectional Mendelian randomization (MR) to uncover the causal pathways between BMD, BMI and OA.

METHODS

One-sample (1S)MR estimates were generated by two-stage least-squares regression. Unweighted allele scores instrumented each exposure. Two-sample (2S)MR estimates were generated using inverse-variance weighted random-effects meta-analysis. Multivariable MR (MVMR), including BMD and BMI instruments in the same model, determined the BMI-independent causal pathway from BMD to OA. Latent causal variable (LCV) analysis, using weight-adjusted femoral neck (FN)-BMD and hip/knee OA summary statistics, determined whether genetic correlation explained the causal effect of BMD on OA.

RESULTS

1SMR provided strong evidence for a causal effect of BMD estimated from heel ultrasound (eBMD) on hip and knee OA {odds ratio [OR]hip = 1.28 [95% confidence interval (CI) = 1.05, 1.57], p = 0.02, ORknee = 1.40 [95% CI = 1.20, 1.63], p = 3 × 10-5, OR per standard deviation [SD] increase}. 2SMR effect sizes were consistent in direction. Results suggested that the causal pathways between eBMD and OA were bidirectional (βhip = 1.10 [95% CI = 0.36, 1.84], p = 0.003, βknee = 4.16 [95% CI = 2.74, 5.57], p = 8 × 10-9, β = SD increase per doubling in risk). MVMR identified a BMI-independent causal pathway between eBMD and hip/knee OA. LCV suggested that genetic correlation (i.e. shared genetic aetiology) did not fully explain the causal effects of BMD on hip/knee OA.

CONCLUSIONS

These results provide evidence for a BMI-independent causal effect of eBMD on OA. Despite evidence of bidirectional effects, the effect of BMD on OA did not appear to be fully explained by shared genetic aetiology, suggesting a direct action of bone on joint deterioration.

A comparison, using X-ray micro-computed tomography, of the architecture of cancellous bone from the cervical, thoracic and lumbar spine using 240 vertebral bodies from 10 body donors

The vertebral trabecular bone has a complex three-dimensional microstructure with an inhomogeneous morphology. Correct identification and assessment of the weakest segments of the cancellous bone may lead to better prediction of fracture risk. The aim of this study was to compare cancellous bone from 240 vertebrae of the cervical, thoracic and lumbar spine of ten body donors with osteoporosis in regard to bone volume fraction (BVF), trabecular thickness, separation, trabecular number and degree of anisotropy, to ascertain why cervical vertebrae rarely fracture, even with severe osteoporosis. Samples were obtained from all vertebrae with a Jamshidi needle (8 Gauge). The investigations were performed with a micro-computed tomography (micro-CT) device (SKYSCAN 1172, RJL Micro & Analytic GmbH, Karlsdorf-Neuthard, Germany). Existing vertebral fractures and the bone mineral density of the lumbar spine were assessed with quantitative CT. Regarding the micro-CT parameters, statistically significant differences were observed between the various sections of the spine. We found a higher BVF, trabecular number and trabecular thickness, as well as a lower trabecular separation of the cervical vertebrae compared to other vertebrae. In addition, the degree of anisotropy in the cervical spine is lower than in the other spinal column sections. These results are age and sex dependent. Thus, the cervical spine has special structural features, whose causes must be determined in further investigations.

The effect of high-dose vitamin D3 supplementation on bone mineral density in subjects with prediabetes

The rationale of this study was to determine the effect of high-dose vitamin D₃ supplementation on bone mineral density (BMD). Prediabetic males given vitamin D had significantly less reduction in BMD at the femoral neck compared to the controls. The clinical implications of our findings require further investigation.

INTRODUCTION

Type 2 diabetes mellitus is associated with increased fracture risk, and recent studies show crosstalk between bone and glucose metabolism. Few studies have investigated the effect of vitamin D supplementation on the bone without additional calcium. In the present study, we aimed to determine whether a high dose of vitamin D₃ could improve bone mass density (BMD) in prediabetic subjects.

METHODS

The current study was conducted as a secondary research on a previously performed trial, in which 511 subjects with prediabetes were randomized to vitamin D₃ (20,000 IU per week) versus placebo for 5 years. BMD was measured using dual-energy X-ray absorptiometry (DEXA).

RESULTS

Two hundred and fifty-six subjects were randomized to vitamin D and 255 to placebo. Mean baseline serum 25-hydroxyvitamin D (25(OH)D) level was 60 nmol/L. Two hundred and two and 214 in the vitamin D and placebo groups, respectively, completed BMD measurements, whereas one in each group was excluded due to use of bisphosphonates. Males given vitamin D had significantly less reduction in BMD at the femoral neck measurement site compared to the controls (0.000 versus - 0.010 g/cm², p = 0.008). No significant differences between intervention groups were seen at the total hip measurement site, regarding both males and females.

CONCLUSIONS

Vitamin D₃ supplementation alone may be beneficial in males with prediabetes, but confirmatory studies are needed.

Hip Fracture Types in Canadian Men and Women Change Differently with Age: A Population-Level Analysis

BACKGROUND

We have previously reported a gender difference in the occurrence of hip fracture type with age in our local population. In the current report, we have explored this phenomenon in a Canadian population using five years of data from a national administrative database. We have compared community-dwelling and institutionalized individuals to determine if frailty is important and has a differential effect on the type of hip fracture experienced.

METHODS

Hospitalization records from 2005 to 2009, in which the most responsible diagnosis, that is the diagnosis causing the admission to hospital, was a hip fracture, were obtained from the Discharge Abstract Database of the Canadian Institute for Health Information. Hip fracture type was identified using the Canadian Classification of Health Interventions and the International Classification of Diseases 10th Revision, Canada (ICD-10-CA). Hip fracture proportions were calculated for the study period and stratified by age group and sex.

RESULTS

The relative proportion of intertrochanteric fractures in women rose from 35% in the youngest group (55-59 years) to 51% in the oldest group (84+ years; P < 0.0001). In men, the proportions remain relatively stable (47% and 44%, respectively). Community and institutionalized patients showed the same pattern.

CONCLUSIONS

The change in the proportion of the two hip fracture types that occur in women but not men may point to differences in the etiology and consequently the approaches to prevention for the two fracture types. Level of frailty did not seem to be important.

Prevalence and predictors of low bone mineral density and fragility fractures among HIV-infected patients at one Italian center after universal DXA screening: sensitivity and specificity of current guidelines on bone mineral density management

Low bone mineral density (BMD) is frequent in HIV infection regardless of the use of antiretroviral therapy (ART). Uncertainties remain, however, as to when in HIV infection BMD screening should be performed. We designed a prospective study to estimate the efficacy of universal BMD screening by dual-energy X-ray absorptiometry (DXA). Since April 2009 through March 2011, HIV patients attending our Center were offered femoral/lumbar DXA to screen BMD. Low BMD for chronological age, that is significant osteopenia, was defined as a Z-score ≤ -2.0 at femur and lumbar spine. Nontraumatic bone fractures (NTBFs) were evaluated. The final sample included 163 patients. A Z-score ≤ -2.0 at any site was observed in 19.6% of cases: among these, 18.8% had no indication to DXA using current Italian HIV guidelines for BMD screening. A lower femoral Z-score was independently associated with lower BMI, AIDS diagnosis, HCV co-infection, antiretroviral treatment, and NTBFs; a lower lumbar Z-score with age, BMI, Nadir CD4 T-cell counts, and NTBFs. Prevalence of NTBFs was 27.0%, predictors being male gender, HCV co-infection, and lower femoral Z-scores. Our results suggest that measuring BMD by DXA in all HIV patients regardless of any further specification may help retrieving one-fifth of patients with early BMD disorders not identified using current criteria for selective screening of BMD.

Distribution of vertebral fractures varies among patients according to hip fracture type

This study explored the distribution of vertebral fractures in hip fracture patients. Unlike patients with intertrochanteric fractures, those with subcapital fractures were less likely to have vertebral fractures in the T4-T10 region of the spine. The dissimilar distribution of vertebral fractures among patients with intertrochanteric and subcapital fractures may indicate different underlying etiologies.

INTRODUCTION

There are two main types of hip fractures: intertrochanteric and subcapital. Both types can have associated vertebral fractures. In this study, we explored the distribution of vertebral fractures in the two hip fracture populations.

METHODS

This was a retrospective analysis of a convenience sample of 120 patients: 40 with subcapital fractures and vertebral fractures, 40 with intertrochanteric fractures and vertebral fractures, and 40 with vertebral fractures only. Based on Genant's semiquantitative assessment method of radiographic images, the distribution and severity of each patient's vertebral fractures were explored [1].

RESULTS

Patients with subcapital fractures had significantly fewer total vertebral fractures (93 vs. 144, p = 0.005; 93 vs. 127, p = 0.019), vertebral fractures from T4 to T10 (41 vs. 81, p = 0.005; 41 vs. 64, p = 0.042), and vertebral fractures at the T7-T8 peak (11 vs. 31, p = 0.002; 11 vs. 30, p = 0.003) than patients with intertrochanteric fractures and those with vertebral fractures alone, respectively, and they were more likely to have only one vertebral fracture (15 vs. 3, p < 0.001; 15 vs. 2, p < 0.001). The number of vertebral fractures from T11 to L4 and at the T12-L1 peak did not differ among the groups. The numbers of fractures at each vertebral level was significantly correlated only between those with intertrochanteric fractures and those with vertebral fractures alone (r = 0.65, p = 0.009).

CONCLUSION

The distribution of vertebral fractures among patients with subcapital fractures differed from the other fracture groups, which may indicate that subcapital fractures and some lumbar fractures have a different underlying etiology than intertrochanteric fractures and thoracic (T4-T10) fractures.

Comparison of hip fracture and osteoporosis medication prescription rates across Canadian provinces

The study explores osteoporosis medication prescribing across Canadian provinces and any impact on hip fracture rates. Despite a marked variation in the prescribing of such medication, there is no effect on the hip fracture rate in either gender or any age group, suggesting either poor targeting or lack of efficacy.

INTRODUCTION

Hip fractures are the most disabling and costly of osteoporotic fractures, and a reduction in the risk of hip fracture is an expectation of osteoporosis medications. In this study, we have compared the use of osteoporosis medication across Canadian provinces with the rate of hip fractures in the same regions.

METHODS

Three years of hip fracture data (2007-2009 inclusive) were obtained from the Canadian Institute for Health Information for all Canadian provinces excluding Quebec. Population information was obtained from Statistics Canada and medication information from the Brogan Inc. database. Because osteoporosis medication is available daily, weekly, monthly, and yearly, medication prescriptions were converted to "units" of prescribing, so that a once a year infusion represented 365 units, a monthly prescription 30 units, and so forth.

RESULTS

There is a fourfold difference in prescribing across provinces but no corresponding variation in hip fracture rate. No significant correlation exists between prescribing load and hip fracture rate. This was true for all age groups, both genders, and for both intertrochanteric and subcapital hip fracture.

CONCLUSIONS

We find no association between osteoporosis medication prescribing and hip fracture rate. Possible explanations include insufficient numbers of at-risk patients on treatment, inappropriate targeting, and either lack of efficacy or efficacy limited to only certain subgroups of patients such as those with demonstrable trabecular osteoporosis.