Vertebral fracture risk reduction with strontium ranelate in women with postmenopausal osteoporosis is independent of baseline risk factors

Fracture rates in patients discontinuing alendronate treatment in real life: a population-based cohort study

In this nationwide register-based cohort study, we found no difference in the risk of fractures in patients discontinuing versus continuing alendronate (ALN) treatment after 5 years.

INTRODUCTION

Information on fracture risk in patients discontinuing ALN in a real-life setting is sparse. We aimed to examine ALN discontinuation patterns, compare fracture rates in patients discontinuing versus continuing ALN after 5 years of treatment, and define determinants of fractures in ALN discontinuers.

METHODS

A nationwide population-based cohort study using Danish health registry data. Our source population was individuals who had redeemed ≥ 2 ALN prescriptions between January 1, 1995, and September 1, 2017.

RESULTS

We found that 25% of all ALN initiators used ALN for less than 1 year and 43% continued treatment for at least 5 years. We classified n = 1865 as ALN discontinuers and n = 29,619 as ALN continuers. Using Cox proportional hazards regression analysis and an "as-treated" approach, we observed no increased risk of any fracture (incidence rate ratio (IRR) 1.06, 95% CI 0.92-1.23), vertebral fracture (IRR 0.59, 95% CI 0.33-1.05), hip fracture (IRR 1.04, 95% CI 0.75-1.45), or major osteoporotic fracture (IRR 1.05, 95% CI 0.88-1.25) in the ALN discontinuers compared to continuers during a follow-up time of 1.84 ± 1.56 years (mean ± SD) and 2.51 ± 1.60 years, respectively. ALN re-initiation was a major determinant of follow-up among the discontinuers. Old age (> 80 vs. 50-60 years, unadjusted IRR 2.92, 95% CI 1.18-7.24) was the strongest determinant for fractures following ALN discontinuation.

CONCLUSION

In a real-world setting, less than 50% continued ALN treatment for 5 years. We found no difference in the risk of fractures in patients discontinuing versus continuing ALN after 5 years.

Upper Extremity Fragility Fractures

The population of elderly patients is rapidly increasing in the United States and worldwide, leading to an increased prevalence of osteoporosis and a concurrent rise in fragility fractures. Fragility fractures are defined as fractures involving a low-energy mechanism, such as a fall from a standing height or less, and have been associated with a significant increase in the risk of a future fragility fracture. Distal radius fractures in the elderly often present earlier than hip and vertebral fractures and frequently involve underlying abnormalities in bone mass and microarchitecture. This affords a unique opportunity for upper extremity surgeons to aid in the diagnosis and treatment of osteoporosis and the prevention of secondary fractures. This review aims to outline current recommendations for orthopedic surgeons in the evaluation and treatment of upper extremity fragility fractures.

Fracture prediction, imaging and screening in osteoporosis

Osteoporosis is associated with increased fragility of bone and a subsequent increased risk of fracture. The diagnosis of osteoporosis is intimately linked with the imaging and quantification of bone and BMD. Scanning modalities, such as dual-energy X-ray absorptiometry or quantitative CT, have been developed and honed over the past half century to provide measures of BMD and bone microarchitecture for the purposes of clinical practice and research. Combined with fracture prediction tools such as Fracture Risk Assessment Tool (FRAX) (which use a combination of clinical risk factors for fracture to provide a measure of risk), these elements have led to a paradigm shift in the ability to diagnose osteoporosis and predict individuals who are at risk of fragility fracture. Despite these developments, a treatment gap exists between individuals who are at risk of osteoporotic fracture and those who are receiving therapy. In this Review, we summarize the epidemiology of osteoporosis, the history of scanning modalities, fracture prediction tools and future directions, including the most recent developments in prediction of fractures.

We miss the opportunity: Pretreament of osteoporosis in a German trauma center

Osteoporosis remains a major health concern due to high incidence of fragility fractures followed by higher mortality and morbidity. Implementation of guidelines for diagnosis and treatment of osteoporosis is critically discussed internationally. Aim of this study was to evaluate implementation of these guidelines regarding diagnosis and therapy of osteoporosis in a developed western country. We hypothesized that (a) prior diagnosis of osteoporosis in patients with low-energy fractures is higher than the estimated incidence and (b) diagnosis and therapy of osteoporosis in patients with prior low-energy fractures is higher than in patients without prior low-energy fractures. 399 patients >60 years suffering low-energy-fractures of their spine, femur, humerus or forearm between 03/2014 and 04/2015 were recruited in a German trauma center. All received a standardized interview. In 21% (84/399) of all patients, osteoporosis was diagnosed prior to current admission. 34% (136/399) suffered a prior risk-fracture after age of 50. Of these, only 54% (73/136) reported about following dual-energy X-ray absorptiometry (DXA) to test for decreased bone-marrow-density with positive results in 68% (50/73). 38% (19/50) of these patients with fragility fractures and prior osteoporosis diagnosis received anti-osteoporotic medication. 66% (263/399) of all patients had no prior risk-fracture and were tested for osteoporosis by DXA in 36% (95/263), leading to positive results in 34% (32/95). 44% (14/32) of these patients received anti-osteoporotic medication. Applying FRAX, 33% of all patients showed a calculated 10-year-risk >20% for suffering a major osteoporotic fracture. 61% (83/136) of patients with a prior fracture had a 10-year-risk >20% of which 47% (39/83) patients received no prior DXA. Although guidelines recommend diagnosis and treatment of patients with low-energy fractures, opportunity for early treatment following risk fractures seems rarely used. Expedient risk assessment is necessary to indicate further diagnostics and therapy of osteoporosis to ensure adequate and efficient treatment for osteoporotic fractures.

A brief history of FRAX

This paper reviews the research programme that went into the development of FRAX® and its impact in the 10 years since its release in 2008.

INTRODUCTION

Osteoporosis is defined on the measurement of bone mineral density though the clinical consequence is fracture. The sensitivity of bone mineral density measurements for fracture prediction is low, leading to the development of FRAX to better calculate the likelihood of fracture and target anti-osteoporosis treatments.

METHODS

The method used in this paper is literature review.

RESULTS

FRAX, developed over an 8-year period, was launched in 2008. Since the launch of FRAX, models have been made available for 64 countries and in 31 languages covering more than 80% of the world population.

CONCLUSION

FRAX provides an advance in fracture risk assessment and a reference technology platform for future improvements in performance characteristics.

Mind the (treatment) gap: a global perspective on current and future strategies for prevention of fragility fractures

This narrative review considers the key challenges facing healthcare professionals and policymakers responsible for providing care to populations in relation to bone health. These challenges broadly fall into four distinct themes: (1) case finding and management of individuals at high risk of fracture, (2) public awareness of osteoporosis and fragility fractures, (3) reimbursement and health system policy and (4) epidemiology of fracture in the developing world. Findings from cohort studies, randomised controlled trials, systematic reviews and meta-analyses, in addition to current clinical guidelines, position papers and national and international audits, are summarised, with the intention of providing a prioritised approach to delivery of optimal bone health for all. Systematic approaches to case-finding individuals who are at high risk of sustaining fragility fractures are described. These include strategies and models of care intended to improve case finding for individuals who have sustained fragility fractures, those undergoing treatment with medicines which have an adverse effect on bone health and people who have diseases, whereby bone loss and, consequently, fragility fractures are a common comorbidity. Approaches to deliver primary fracture prevention in a clinically effective and cost-effective manner are also explored. Public awareness of osteoporosis is low worldwide. If older people are to be more pro-active in the management of their bone health, that needs to change. Effective disease awareness campaigns have been implemented in some countries but need to be undertaken in many more. A major need exists to improve awareness of the risk that osteoporosis poses to individuals who have initiated treatment, with the intention of improving adherence in the long term. A multisector effort is also required to support patients and their clinicians to have meaningful discussions concerning the risk-benefit ratio of osteoporosis treatment. With regard to prioritisation of fragility fracture prevention in national policy, there is much to be done. In the developing world, robust epidemiological estimates of fracture incidence are required to inform policy development. As the aging of the baby boomer generation is upon us, this review provides a comprehensive analysis of how bone health can be improved worldwide for all.

Dose-dependent Effects of Strontium Ranelate on Ovariectomy Rat Bone Marrow Mesenchymal Stem Cells and Human Umbilical Vein Endothelial Cells

In clinic, strontium ranelate (SrR) is a useful drug to treat osteoporosis by orally taken method, but some side effect appeared in recent years. The aim of this study is to evaluate the effectiveness and safety of SrR on cells by direct application, to study the possibility of local application of this drug. Qualitative ALP staining, quantitative ALP activity assay, alizarin red staining, realtime PCR and westernblot assay were used to evaluate the osteogenesis ability of SrR under normal or osteogenic induction environment of ovariectomy bone marrow mesenchymal stem cells (OVX-BMSCs). The angiogenesis ability of SrR was studied by immunofluorescence staining of CD31 and vWF of OVX-BMSCs under angiogenesis induction environment, transwell, tubeformation and realtime PCR assay of HUVECs. Signaling pathway of PI3K/AKT/mTOR was also studied. The result demonstrated that SrR could enhance proliferation and osteogenic differentiation of OVX-BMSCs. The osteogenesis effect of SrR has been proved by the better performed of ALP activity, alizarin red staining and the remarkable up-regulation of ALP, Col-I, Runx2, OCN, BMP-2, BSP, OPG of the OVX-BMSCs, and reduction of RANKL. In addition, SrR promotes angiogenesis differentiation of both OVX-BMSCs and HUVECs. Higher intensity of immunostaining of CD31 and vWF, better result of transwell and tubeformation assay could be observed in SrR treated group, and increasing mRNA levels of VEGF and Ang-1 in the OVX-BMSCs, VEGF in HUVECs were learnt. Signaling pathway assay showed that PI3K/AKT/mTOR signaling pathway was involved in this SrR triggered angiogenesis procedure. The thrombosis marker ET-1, PAI-1 and t-PA were up-regulated, but no significant differences for low concentration (<0.5mM). The concentration between 0.25-0.5mM may be more appropriate for local application, and locally application of SrR could be considered as a promising way for bone regeneration.

FRAX updates 2016

PURPOSE OF REVIEW

In the 8 years since the launch of the FRAX tool, it has continued to grow with the addition of new country or territory models. Although the core of the fracture risk algorithm remains unchanged, there is growing evidence of possible additional independent clinical variables that might modulate the interpretation of the FRAX outputs. There is also an expanding number of international guidelines that incorporate FRAX assessments, leading to discussions on the use of FRAX in treated patients and the determination of intervention thresholds.

RECENT FINDINGS

This review encompasses recent information on the use of FRAX in immigrant populations and the potential influence of skeletal and extraskeletal risk factors on FRAX estimations. For example, trabecular bone score and falls risk appear to be promising additional factors in individual risk assessment. FRAX appears to remain accurate in those on osteoporosis treatments, but FRAX is not a suitable tool for use in treat-to-target strategies.

SUMMARY

The assessment of fracture risk in immigrants is probably more accurate with the use of the FRAX tool for the country of origin, if available. The impact of additional risk variables will need evaluation of the impact of these on recharacterizing patients by moving them across intervention thresholds.

FRAX and fracture prediction without bone mineral density

The major application of FRAX in osteoporosis is to direct pharmacological interventions to those at high risk of fracture. Whereas the efficacy of osteoporosis treatment, with the possible exception of alendronate, is largely independent of baseline bone mineral density (BMD), it remains a widely held perception that osteoporosis therapies are only effective in the presence of low BMD. Thus, the use of FRAX in the absence of BMD to identify individuals requiring therapy remains the subject of some debate and is the focus of this review. The clinical risk factors used in FRAX have high evidence-based validity to identify a risk responsive to intervention. The selection of high-risk individuals with FRAX, without knowledge of BMD, preferentially selects for low BMD and thus identifies a risk that is responsive to pharmacological intervention. The prediction of fractures with the use of clinical risk factors alone in FRAX is comparable to the use of BMD alone to predict fractures and is suitable, therefore, in the many countries where facilities for BMD testing are sparse. In countries where access to BMD is greater, FRAX can be used without BMD in the majority of cases and BMD tests reserved for those close to a probability-based intervention threshold. Thus concerns surrounding the use of FRAX in clinical practice without information on BMD are largely misplaced.

Efficacy and safety of currently marketed anti-osteoporosis medications

During the past 2 decades, many interventions were proven effective in the management of postmenopausal osteoporosis. The objective of an anti-osteoporosis treatment is to reduce fracture rates, ideally at all skeletal sites (i.e. spine, hip, and other non-spine). The armamentarium against osteoporosis includes anti-resorptive agents (i.e. bisphosphonates, selective estrogen receptor modulators and denosumab), bone-forming agents (i.e. peptides from the parathyroid hormone family) and one agent with a dual mechanism of action (i.e. strontium ranelate). All these medications combine antifracture efficacy with a reasonable benefit/risk profile. However, the choice of a particular chemical entity, in one individual patient is based on the knowledge and expertise of the physician. Prioritization of drugs should be based on the individual profile of the patient, the severity of osteoporosis and the specific contraindications, warnings and precautions of use of the various available medications.

Aspartic acid-based modified PLGA-PEG nanoparticles for bone targeting: in vitro and in vivo evaluation

Nanoparticles (NP) that target bone tissue were developed using PLGA-PEG (poly(lactic-co-glycolic acid)-polyethylene glycol) diblock copolymers and bone-targeting moieties based on aspartic acid, (Asp)(n(1,3)). These NP are expected to enable the transport of hydrophobic drugs. The molecular structures were examined by (1)H NMR or identified using mass spectrometry and Fourier transform infrared (FT-IR) spectra. The NP were prepared using the water miscible solvent displacement method, and their size characteristics were evaluated using transmission electron microscopy (TEM) and dynamic light scattering. The bone targeting potential of the NP was evaluated in vitro using hydroxyapatite affinity assays and in vivo using fluorescent imaging in zebrafish and rats. It was confirmed that the average particle size of the NP was <200 nm and that the dendritic Asp3 moiety of the PLGA-PEG-Asp3 NP exhibited the best apatite mineral binding ability. Preliminary findings in vivo bone affinity assays in zebrafish and rats indicated that the PLGA-PEG-ASP3 NP may display increased bone-targeting efficiency compared with other PLGA-PEG-based NP that lack a dendritic Asp3 moiety. These NP may act as a delivery system for hydrophobic drugs, warranting further evaluation of the treatment of bone disease.

Prevention of incident fractures in patients with prevalent fragility fractures: Current and future approaches

Fragility fractures are a significant, independent risk factor for new fractures, but treatment uptake in subjects with prevalent fractures is disappointing. We addressed the question of the efficacy of pharmacological interventions in reducing the risk of incident fractures in patients with prevalent fragility fractures. For this, we reviewed randomised controlled trials (RCTs), pre-planned and post-hoc analyses of RCTs of approved agents for the treatment of osteoporosis. Results showed that a number of agents decrease the risk of incident vertebral and nonvertebral fractures in subjects with prevalent vertebral fractures, justifying the recommendation of treating such patients independently of the level of bone mineral density (BMD). By contrast, the evidence of antifracture efficacy of these agents in patients with prevalent nonvertebral fractures is limited. Advances in our understanding of the regulation of bone metabolism at the molecular level have identified targets for the development of new therapeutics for osteoporosis, some of which are currently in phase 3 clinical development.

The coupling of bone and cartilage turnover in osteoarthritis: opportunities for bone antiresorptives and anabolics as potential treatments?

Osteoarthritis (OA) is the most common form of arthritic disease, and a major cause of disability and impaired quality of life in the elderly. OA is a complex disease of the entire joint, affecting bone, cartilage and synovium that thereby presents multiple targets for treatment. This manuscript will summarise emerging observations from cell biology, preclinical and preliminary clinical trials that elucidate interactions between the bone and cartilage components in particular. Bone and cartilage health are tightly associated. Ample evidence has been found for bone changes during progression of OA including, but not limited to, increased turnover in the subchondral bone, undermineralisation of the trabecular structure, osteophyte formation, bone marrow lesions and sclerosis of the subchondral plate. Meanwhile, a range of investigations has shown positive effects on cartilage health when bone resorption is suppressed, or deterioration of the cartilage when resorption is increased. Known bone therapies, namely oestrogens, selective oestrogen receptor modifiers (SERMs), bisphosphonates, strontium ranelate, calcitonin and parathyroid hormone, might prove useful for treating two critical tissue components of the OA joint, the bone and the cartilage. An optimal treatment for OA likely targets at least these two tissue components. The patient subgroups for whom these therapies are most appropriate have yet to be fully defined but would likely include, at a minimum, those with high bone turnover.

Cost-effectiveness of strontium ranelate in the treatment of male osteoporosis

The results of this study suggest that, under the assumption of same relative risk reduction of fractures in men as for women, strontium ranelate could be considered a cost-effective strategy compared with no treatment for the treatment of osteoporotic men from a Belgian healthcare payer perspective.

INTRODUCTION

This study was conducted to estimate the cost-effectiveness of strontium ranelate in the treatment of osteoporotic men.

METHODS

A previously validated Markov microsimulation model was adapted to estimate the cost (<euro>2,010) per quality-adjusted life-year (QALY) gained of strontium ranelate compared with no treatment. Similar efficacy data on lumbar spine and femoral neck bone mineral density (BMD) between men with osteoporosis at high risk of fracture (MALEO Trial) and postmenopausal osteoporotic women (pivotal SOTI, TROPOS trials) supports the assumption, in the base-case analysis, of the same relative risk reduction of fractures in men as for women. Analyses were conducted, from a Belgian healthcare payer perspective, in the population from the MALEO Trial who is a men population with a mean age of 73 years, and BMD T-score ≤-2.5 or prevalent vertebral fracture (PVF).

RESULTS

In the MALEO population, strontium ranelate compared with no treatment was estimated at <euro>49,798 and <euro>25,584 per QALY gained using efficacy data from the intent-to-treat analysis and the per-protocol analysis including only adherent patients, respectively. In men with a BMD T-score ≤-2.5 or with PVF, the cost per QALY gained of strontium ranelate fall below thresholds of <euro>45,000 and <euro>25,000 per QALY gained based on efficacy data from the entire population of the clinical trial and from the per-protocol analyses, respectively.

CONCLUSIONS

The results of this study suggest that, under the assumption of same relative risk reduction of fractures in men as for women, strontium ranelate could be considered cost-effective compared with no treatment for male osteoporosis.

Porous allograft bone scaffolds: doping with strontium

Strontium (Sr) can promote the process of bone formation. To improve bioactivity, porous allograft bone scaffolds (ABS) were doped with Sr and the mechanical strength and bioactivity of the scaffolds were evaluated. Sr-doped ABS were prepared using the ion exchange method. The density and distribution of Sr in bone scaffolds were investigated by inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray spectroscopy (EDS). Controlled release of strontium ions was measured and mechanical strength was evaluated by a compressive strength test. The bioactivity of Sr-doped ABS was investigated by a simulated body fluid (SBF) assay, cytotoxicity testing, and an in vivo implantation experiment. The Sr molar concentration [Sr/(Sr+Ca)] in ABS surpassed 5% and Sr was distributed nearly evenly. XPS analyses suggest that Sr combined with oxygen and carbonate radicals. Released Sr ions were detected in the immersion solution at higher concentration than calcium ions until day 30. The compressive strength of the Sr-doped ABS did not change significantly. The bioactivity of Sr-doped material, as measured by the in vitro SBF immersion method, was superior to that of the Sr-free freeze-dried bone and the Sr-doped material did not show cytotoxicity compared with Sr-free culture medium. The rate of bone mineral deposition for Sr-doped ABS was faster than that of the control at 4 weeks (3.28±0.23 µm/day vs. 2.60±0.20 µm/day; p<0.05). Sr can be evenly doped into porous ABS at relevant concentrations to create highly active bone substitutes.

In vitro bone exposure to strontium improves bone material level properties

In rats treated with strontium ranelate, the ultimate load of intact bone is increased and associated with changes in microstructure and material level properties. Evaluation by micro-computed-tomography-based finite element analysis has shown that these changes independently contribute to the improvement of bone strength induced by strontium ranelate treatment. However, the mechanism by which Sr ion acts on bone material level properties remains unknown. The vertebrae of intact female rats were exposed overnight to 0.5, 1 or 2M chloride salt solutions of Sr, Ca and Ba. The latter two were used to assess the specificity of Sr. Bone material level properties were evaluated by measuring hardness, elastic modulus and working energy in a nanoindentation test. Wavelength dispersive X-ray spectroscopy provided semi-quantitative elemental analysis and mapping. Incubation with Sr rendered bone stiffer, harder and tougher. Among the divalent ions tested, Sr had the greatest effect. Sr affinity was also assessed on in vivo treated bone specimens. After in vitro exposure, the highest improvements were observed in ovariectomized rats. However, anti-osteoporotic treatments did not influence the capacity of Sr to modify bone material level properties. Our findings demonstrated that in vitro incubation with Sr selectively improved bone material level properties, which may contribute to the macroscopic increase of bone properties observed under Sr therapy.

A review on strontium ranelate long-term antifracture efficacy in the treatment of postmenopausal osteoporosis

Osteoporotic fractures are one of the major causes of increased morbidity and mortality in postmenopausal women and the overall aging population. One of the major issues in the management of postmenopausal osteoporosis is to find a safe and effective treatment in the long term (>3 years) to achieve and maintain a reduction in the risk of fracture. Strontium ranelate (PROTELOS(®)) is a relatively novel drug, currently approved in Europe for the treatment of postmenopausal osteoporosis. Strontium ranelate is the first agent of a new therapeutic class in osteoporosis, capable of both promoting bone formation and, to a lesser extent, inhibiting bone resorption. This uncoupling in bone turnover results in a net gain in bone mineral density (BMD), bone quality improvement and reduction in risk of vertebral and nonvertebral fractures, as initially demonstrated in the preplanned long-term registrative trials SOTI (Spinal Osteoporosis Therapeutic Intervention) and TROPOS (Treatment of Peripheral Osteoporosis) at 5 years. Recently, open-label extensions of the SOTI and TROPOS trials up to 8 and, recently, 10 years have confirmed the sustained efficacy of strontium ranelate in increasing BMD, the long-term safety profile and the high compliance to treatment, independently from baseline BMD or other risk factors for osteoporotic fractures. Recent economic impact analyses have proved that long-term treatment with strontium ranelate is highly cost effective, especially in women older than 70 years of age. Histomorphometric analyses in animals and humans participating in the phase III trials have proved that the quality of mineralization is preserved in the long term and bone microarchitecture is ameliorated, with increased bone strength. Thus, strontium ranelate has been confirmed to be an effective compound for the long-term, chronic treatment of postmenopausal osteoporosis.

Hospitalized osteoporotic vertebral fracture increases the risk of stroke: a population-based cohort study

The association between osteoporosis and cardiovascular diseases has been demonstrated. Higher cardiovascular risk has also been correlated with vertebral fractures. However, the association between osteoporotic vertebral fracture and the possibly higher risk of stroke remains uncertain. This study aimed to evaluate the incidence, risk, and type of stroke in patients with osteoporotic vertebral fracture. Patients with osteoporotic vertebral fracture were identified (n = 380) and 10 age- and sex-matched controls per case (comparison group, n = 3795) were chosen from a nationwide representative cohort of 999,997 people from 1998 to 2005. Both groups were followed-up for stroke events for 3 years, matched by propensity scores with adjustments for covariates such as comorbidities (ie, hypertension, diabetes, arrhythmia, or coronary heart diseases) and exposure to medications (ie, aspirin, lipid lowering drug, or nitrates), and assessed by Kaplan-Meier and Cox regression analyses. The incidence rate of stroke in the osteoporotic vertebral fracture group (37.5 per 1000 person-years; 95% confidence interval [CI], 27.5-51.2) was significantly higher than in the comparison group (14.0 per 1000 person-years; 95% CI, 12.0-16.4, p < 0.001). Stroke was more likely to occur in the osteoporotic vertebral fracture patients than in the normal controls (crude hazard ratio [HR] 2.68, 95% CI 1.89-3.79, p < 0.001; adjusted HR 2.71, 95% CI 1.90-3.86, p < 0.001). In conclusion, patients with osteoporotic vertebral fracture have a higher risk of stroke (ie, both ischemic and hemorrhagic) and require stroke prevention strategies.

A pragmatic randomised controlled trial of the effectiveness and cost-effectiveness of screening older women for the prevention of fractures: rationale, design and methods for the SCOOP study

SCOOP is a UK seven-centre, pragmatic, randomised controlled trial with 5-year follow-up, including 11,580 women aged 70 to 85 years, to assess the effectiveness and cost-effectiveness of a community-based screening programme to reduce fractures. It utilises the FRAX algorithm and DXA to assess the 10-year probability of fracture. Introduction Osteoporotic, or low-trauma, fractures present a considerable burden to the National Health Service and have major adverse effects on quality of life, disability and mortality for the individual. Methods Given the availability of efficacious treatments and a risk assessment tool based upon clinical risk factors and bone mineral density, a case exists to undertake a community-based controlled evaluation of screening for subjects at high risk of fracture, under the hypothesis that such a screening programme would reduce fractures in this population. Results This study is a UK seven-centre, unblinded, pragmatic, randomised controlled trial with a 5-year follow-up period. A total of 11,580 women, aged 70 to 85 years and not on prescribed bone protective therapy will be consented to the trial by post via primary care providing 90% power to detect an 18% decrease in fractures. Conclusions Participants will be randomised to either a screening arm or control. Those undergoing screening will have a 10-year fracture probability computed from baseline risk factors together with bone mineral density measured by DXA in selected subjects. Individuals above an age-dependent threshold of fracture probability will be recommended for treatment for the duration of the trial. Subjects in the control arm will receive 'usual care'. Participants will be followed up 6 months after randomisation and annually by postal questionnaires with independent checking of hospital and primary care records. The primary outcome will be the proportion of individuals sustaining fractures in each group. An economic analysis will be carried out to assess cost-effectiveness of screening. A qualitative evaluation will be conducted to examine the acceptability of the process to participants.

Poncirin prevents bone loss in glucocorticoid-induced osteoporosis in vivo and in vitro

Poncirin, a flavonoid isolated from the fruit of Poncirus trifoliata, possesses anti-bacterial and anti-inflammatory activities. However, the action of poncirin in bone biology is unclear. In this study, the in vivo and in vitro effects of poncirin in a glucocorticoid-induced osteoporosis (GIO) mouse model were investigated. Seven-month-old male mice were assigned to the following five groups: (1) sham-implantation (sham), (2) prednisolone 2.1 mg/kg/day (GC), (3) GC treated with 10 mg/kg/day of genistein, (4) GC treated with 3 mg/kg/day of poncirin, (5) and GC treated with 10 mg/kg/day of strontium (GC + SrCl(2)). After 8 weeks, bone loss was measured by microcomputed tomography. Osteocalcin (OC) and C-terminal telopeptides of type I collagen (CTX) were evaluated in sera. Runx2 protein, OC and osteoprotegerin (OPG) mRNA expression, alkaline phosphatase (ALP) activity, and mineral nodule assay were performed in C3H10T1/2 or primary bone marrow stromal cells. Poncirin significantly increased the bone mineral density and improved the microarchitecture. Poncirin increased serum OC, Runx2 protein production, expression of OC and OPG mRNA, ALP activity, and mineral nodule formation; and decreased serum CTX. These effects were more prominent in the poncirin group compared to the other positive control groups (genistein and strontium). The poncirin-mediated restoration of biochemical bone markers, increased bone mineral density, and improved trabecular microarchitecture likely reflect increased bone formation and decreased bone resorption in GIO mice.

Strontium Ranelate: Long-Term Efficacy against Vertebral, Nonvertebral and Hip Fractures in Patients with Postmenopausal Osteoporosis

Osteoporosis treatments need to combine an unequivocally demonstrated reduction of fractures, at various skeletal sites, long-term safety, and a user-friendly profile, optimizing therapeutic adherence. Strontium ranelate is the first compound to simultaneously decrease bone resorption and stimulate bone formation. Its antifracture efficacy, at various skeletal sites, has been established up to 8 years, through studies of the highest methodological standards. Increases in bone mineral density, observed after 1 year of treatment, are predictive of the long-term fracture efficacy, hence suggesting, for the first time in osteoporosis, that bone densitometry can be used as a monitoring tool for both efficacy and compliance. Owing to a positive benefit/risk ratio, strontium ranelate may now be considered as a first-line treatment in the management of osteoporosis.

Denosumab reduces the risk of osteoporotic fractures in postmenopausal women, particularly in those with moderate to high fracture risk as assessed with FRAX

Denosumab has been shown to reduce the incidence of vertebral, nonvertebral, and hip fractures. The aim of the current study was to determine whether the antifracture efficacy of denosumab was dependent on baseline fracture probability assessed by FRAX. The primary data of the phase 3 FREEDOM study of the effects of denosumab in women with postmenopausal osteoporosis were used to compute country-specific probabilities using the FRAX tool (version 3.2). The outcome variable comprised all clinical osteoporotic fractures (including clinical vertebral fractures). Interactions between fracture probability and efficacy were explored by Poisson regression. At baseline, the median 10-year probability of a major osteoporotic fracture (with bone mineral density) was approximately 15% and for hip fracture was approximately 5% in both groups. In the simplest model adjusted for age and fracture probability, treatment with denosumab over 3 years was associated with a 32% (95% confidence interval [CI] 20% to 42%) decrease in clinical osteoporotic fractures. Denosumab reduced fracture risk to a greater extent in those at moderate to high risk. For example, at 10% probability, denosumab decreased fracture risk by 11% (p = 0.629), whereas at 30% probability (90th percentile of study population) the reduction was 50% (p = 0.001). The reduction in fracture was independent of prior fracture, parental history of hip fracture, or secondary causes of osteoporosis. A low body mass index (BMI) was associated with greater efficacy. Denosumab significantly decreased the risk of clinical osteoporotic fractures in postmenopausal women. Overall, the efficacy of denosumab was greater in those at moderate to high risk of fracture as assessed by FRAX.

2012 update of French guidelines for the pharmacological treatment of postmenopausal osteoporosis

OBJECTIVES

To update the evidence-based position statement published by the French National Authority for Health (HAS) in 2006 regarding the pharmacological treatment of postmenopausal osteoporosis, under the auspices of the French Society for Rheumatology and Groupe de Recherche et d'Information sur les Ostéoporoses (GRIO), and with the participation of several learned societies (Collège National des Gynécologues et Obstétriciens Français, Groupe d'Étude de la Ménopause et du Vieillissement hormonal, Société Française de Chirurgie Orthopédique, Société Française d'Endocrinologie, and Société Française de Gériatrie et de Gérontologie).

METHODS

A multidisciplinary panel representing the spectrum of clinical specialties involved in managing patients with postmenopausal osteoporosis developed updated recommendations based on a systematic literature review conducted according to the method advocated by the HAS.

RESULTS

The updated recommendations underline the need for osteoporosis pharmacotherapy in women with a history of severe osteoporotic fracture. In these patients, any osteoporosis medication can be used; however, zoledronic acid is the preferred first-line medication after a hip fracture. In patients with non-severe fractures or no fractures, the appropriateness of osteoporosis pharmacotherapy depends on the bone mineral density and FRAX(®) values; any osteoporosis medication can be used, but raloxifene and ibandronate should be reserved for patients at low risk for peripheral fractures. Initially, osteoporosis pharmacotherapy should be prescribed for 5 years. The results of the evaluation done at the end of the 5-year period determine whether further treatment is in order.

CONCLUSIONS

These updated recommendations are intended to provide clinicians with clarifications about the pharmacological treatment of osteoporosis.

Acceptability of screening to prevent osteoporotic fractures: a qualitative study with older women

BACKGROUND

Osteoporotic fractures have a detrimental impact on health and quality of life, are more common in older women and are costly to treat. Screening to identify older women at high risk of fracture has the potential to offer substantial benefits. Understanding women's and professionals' experiences of screening will inform the implementation of screening in routine care.

OBJECTIVE

To explore the views of older women and GPs about the acceptability of screening to prevent fractures.

METHODS

A qualitative study conducted within a multi-centre randomized controlled trial of the effectiveness and cost-effectiveness of screening women aged 70-85 years for the prevention of fractures; 30 women randomized to the trial screening group and 15 GPs were recruited from general practices in North Somerset and Norfolk, UK. All 30 women and 11 of the GPs participated in face-to-face semi-structured interviews. Four GPs participated in a focus group. Data were analysed thematically, using the Framework Approach.

RESULTS

Women and GPs viewed screening positively, recognizing its potential to improve fracture prevention and future health. Attending screening was not found to result in anxiety or excessive activity restriction. Demonstrating cost-effectiveness was key to the acceptability of screening amongst GPs. Implementing similar screening in routine care would require consideration of access to bone density scans, information provision to participants and mode of administration.

CONCLUSIONS

Our findings suggest an effective and cost-effective screening programme to reduce osteoporotic fractures could be implemented in routine care and would be well received by women and GPs.

Hip cortical thickness assessment in postmenopausal women with osteoporosis and strontium ranelate effect on hip geometry

The aims of this study were to assess the relationship between hip geometry and the 5-yr risk of hip fractures in postmenopausal osteoporotic women and the effects of strontium ranelate on these parameters. Using the 5-yr data of a randomized placebo-controlled trial of strontium ranelate (Treatment of Peripheral Osteoporosis Study [TROPOS]), we reanalyzed the hip dual-energy X-ray absorptiometry scans to determine the role of hip geometry in the risk of hip fractures (placebo group, n=636) and to analyze the effects of strontium ranelate (n=483). The outcomes included the hip structure analysis (HSA) parameters: cross-sectional area (CSA), section modulus, cortical thickness, and buckling ratio, measured at femoral neck, intertrochanteric (IT) region, and proximal shaft. The geometric parameters associated with an increased risk of hip fracture over 5yr were IT CSA and femoral shaft cortical thickness independent of age and total-hip bone mineral density (BMD). Using Bonferroni adjustment, IT cortical thickness was associated with the risk of hip fracture. Over 5yr, significant decreases in some femoral dimensions of the placebo group contrast with significant increases in strontium ranelate group after adjustment for age and BMD. Using Bonferroni adjustment, differences between placebo and strontium ranelate groups were no longer significant after adjustment on 5-yr BMD changes. Some HSA parameters have predictive value for hip fracture risk in postmenopausal osteoporotic women. Strontium ranelate improves some HSA parameters, through the BMD increase.

Maintenance of antifracture efficacy over 10 years with strontium ranelate in postmenopausal osteoporosis

In an open-label extension study, BMD increased continuously with strontium ranelate over 10 years in osteoporotic women (P < 0.01). Vertebral and nonvertebral fracture incidence was lower between 5 and 10 years than in a matched placebo group over 5 years (P < 0.05). Strontium ranelate's antifracture efficacy appears to be maintained long term.

INTRODUCTION

Strontium ranelate has proven efficacy against vertebral and nonvertebral fractures, including hip, over 5 years in postmenopausal osteoporosis. We explored long-term efficacy and safety of strontium ranelate over 10 years.

METHODS

Postmenopausal osteoporotic women participating in the double-blind, placebo-controlled phase 3 studies SOTI and TROPOS to 5 years were invited to enter a 5-year open-label extension, during which they received strontium ranelate 2 g/day (n = 237, 10-year population). Bone mineral density (BMD) and fracture incidence were recorded, and FRAX® scores were calculated. The effect of strontium ranelate on fracture incidence was evaluated by comparison with a FRAX®-matched placebo group identified in the TROPOS placebo arm.

RESULTS

The patients in the 10-year population had baseline characteristics comparable to those of the total SOTI/TROPOS population. Over 10 years, lumbar BMD increased continuously and significantly (P < 0.01 versus previous year) with 34.5 ± 20.2% relative change from baseline to 10 years. The incidence of vertebral and nonvertebral fracture with strontium ranelate in the 10-year population in years 6 to 10 was comparable to the incidence between years 0 and 5, but was significantly lower than the incidence observed in the FRAX®-matched placebo group over 5 years (P < 0.05); relative risk reductions for vertebral and nonvertebral fractures were 35% and 38%, respectively. Strontium ranelate was safe and well tolerated over 10 years.

CONCLUSIONS

Long-term treatment with strontium ranelate is associated with sustained increases in BMD over 10 years, with a good safety profile. Our results also support the maintenance of antifracture efficacy over 10 years with strontium ranelate.

FRAX(®) with and without bone mineral density

The use of FRAX, particularly in the absence of BMD, has been the subject of some debate and is the focus of this review. The clinical risk factors used in FRAX have high validity as judged from an evidence-based assessment and identify a risk that is responsive to pharmaceutical intervention. Moreover, treatment effects, with the possible exception of alendronate, are not dependent on baseline BMD and strongly suggest that FRAX identifies high-risk patients who respond to pharmaceutical interventions. In addition, the selection of high-risk individuals with FRAX, without knowledge of BMD, preferentially selects for low BMD. The prediction of fractures with the use of clinical risk factors alone in FRAX is comparable to the use of BMD alone to predict fractures and is suitable, therefore, in the many countries where DXA facilities are sparse. In countries where access to BMD is greater, FRAX can be used without BMD in the majority of cases and BMD tests reserved for those close to a probability-based intervention threshold. Whereas the efficacy for agents to reduce fracture risk has not been tested prospectively in randomized controlled trials in patients selected on the basis of FRAX probabilities, there is compelling evidence that FRAX with or without the use of BMD provides a well-validated instrument for targeting patients most likely to benefit from an intervention.

Effect of denosumab treatment on the risk of fractures in subgroups of women with postmenopausal osteoporosis

Denosumab reduces the risk of new vertebral and nonvertebral fractures. Previous trials suggest that the efficacy of antiresorptives on fractures might differ by patients' characteristics, such as age, bone mineral density (BMD), and fracture history. In the FREEDOM study, 7808 women aged 60 to 90 years with osteoporosis were randomly assigned to receive subcutaneous injections of denosumab (60 mg) or placebo every 6 months for 3 years. New vertebral and nonvertebral fractures were radiologically confirmed. Subgroup analyses described in this article were prospectively planned before study unblinding to evaluate the effect of denosumab on new vertebral and nonvertebral fractures across various subgroups. Compared with placebo, denosumab decreased the risk of new vertebral fractures in the overall study population over 3 years. This effect did not significantly differ for any of the nine subgroups analyzed (p > 0.09 for all potential interactions). Denosumab also reduced all nonvertebral fractures by 20% in the full study cohort over 3 years. This risk reduction was statistically significant in women with a baseline femoral neck BMD T-score ≤ -2.5 but not in those with a T-score > -2.5; in those with a body mass index (BMI) < 25 kg/m(2) but not ≥ 25 kg/m(2); and in those without but not with a prevalent vertebral fracture. These differential treatment effects were not explained by differences in BMD responses to denosumab. Denosumab 60 mg administered every 6 months for 3 years in women with osteoporosis reduced the risk of new vertebral fractures to a similar degree in all subgroups. The effect of denosumab on nonvertebral fracture risk differed by femoral neck BMD, BMI, and prevalent vertebral fracture at baseline.

Microarchitecture and nanomechanical properties of trabecular bone after strontium administration in osteoporotic goats

Strontium (Sr) ralenate is a new agent used for the prevention and treatment of osteoporosis. As a bone-seeking element, 98% of Sr is deposited in the bone and teeth after oral ingestion. However, the effect of Sr treatment on bone microarchitecture and bone nanomechanical properties remains unclear. In this study, 18 osteoporotic goats were divided into four groups according to the treatment regimen: control, calcium alone (Ca), calcium and Sr at 24 mg/kg (Ca + 24Sr), and calcium and Sr at 40 mg/kg (Ca + 40Sr). The effects of Sr administration on bone microarchitecture and nanomechanical properties of trabecular bones were analyzed with micro-CT and nanoindentation test, respectively. Serum Sr levels increased six- and tenfold in the Ca + 24Sr and Ca + 40Sr groups, respectively. Similarly, Sr in the bone increased four- and sixfold in these two groups. Sr administration significantly increased trabecular bone volume fraction, trabecular thickness, and double-labeled new bone area. Sr administration, however, did not significantly change the nanomechanical properties of trabecular bone (elastic modulus and hardness). The data suggested that Sr administration increased trabecular bone volume and improved the microarchitecture while maintaining the intrinsic tissue properties in the osteoporotic goat model.

A meta-analysis of the effect of strontium ranelate on the risk of vertebral and non-vertebral fracture in postmenopausal osteoporosis and the interaction with FRAX(®)

The aim of the present study was to determine the efficacy of strontium ranelate as a function of baseline fracture risk. Treatment with strontium ranelate was associated with a significant 31% decrease in all clinical osteoporotic fractures (vertebral fractures included). Hazard ratios for the effect of strontium ranelate on the fracture outcome did not change significantly with increasing fracture probability.

INTRODUCTION

Two previous studies have suggested that the efficacy of intervention may be greater in the segment of the population at highest fracture risk as assessed by the FRAX(®) algorithms. The aim of the present study was to determine whether the anti-fracture efficacy of strontium ranelate was dependent of the level of fracture risk.

METHODS

The primary data of the two phase III studies (SOTI and TROPOS) of the effects of strontium ranelate in postmenopausal osteoporosis were combined. Country-specific probabilities were computed using the FRAX(®) tool (version 2.0). The primary outcome variable comprised all clinical osteoporotic fractures (including clinical vertebral fractures). Interactions between fracture probability and efficacy were explored by Poisson regression.

RESULTS

The 10-year probability of major osteoporotic fractures (with BMD) ranged from 2.5% to 90.8%. FRAX(®)-based hip fracture probabilities ranged from 0.1% to 90.3%. The incidence of clinical osteoporotic fractures (vertebral fractures excluded) and morphometric vertebral fractures increased with increasing baseline fracture probabilities. Treatment with strontium ranelate was associated with a 31% (95% CI = 20-39%) decrease in osteoporotic clinical fractures and a 40% decrease in vertebral fractures assessed by semiquantitative morphometry (95% CI = 31-48%) Hazard ratios for the effect of strontium ranelate on the fracture outcomes did not change significantly with increasing fracture probability.

CONCLUSION

Strontium ranelate significantly decreased the risk of osteoporotic clinical fractures, non vertebral fractures and morphometric vertebral fractures in women. Overall, the efficacy of strontium ranelate was not dependent of the level of fracture risk assessed by FRAX.

How strontium ranelate, via opposite effects on bone resorption and formation, prevents osteoporosis

Oestrogen deficiency increases the rate of bone remodelling which, in association with a negative remodelling balance (resorption exceeding formation), results in impaired bone architecture, mass and strength. Current anti-osteoporotic drugs act on bone remodelling by inhibiting bone resorption or by promoting its formation. An alternative therapeutic approach is based on the concept of inducing opposite effects on bone resorption and formation. One therapeutic agent, strontium ranelate, was shown to induce opposite effects on bone resorption and formation in pre-clinical studies and to reduce fracture risk in postmenopausal osteoporotic patients. How strontium ranelate acts to improve bone strength in humans remains a matter of debate, however. This review of the most recent pre-clinical and clinical studies is a critical analysis of strontium ranelate's action on bone resorption and formation and how it increases bone mass, microarchitecture and strength in postmenopausal osteoporotic women.

Increased bone strength is associated with improved bone microarchitecture in intact female rats treated with strontium ranelate: a finite element analysis study

Strontium ranelate has been previously shown to act on bone metabolism and to be effective in postmenopausal osteoporosis treatment by preventing vertebral and non-vertebral fractures. Animal studies explicitly demonstrated that bone strength was improved with strontium ranelate treatment, but the contribution of either improved bone microarchitecture or intrinsic quality of the bone tissue is not clear. Therefore, the purpose of this research was to address this issue by using the unique capability of finite element (FE) analysis to integrate both intrinsic bone quality properties from nano-indentation and microarchitecture measured by micro-computed tomography (μCT). The two groups included intact female Fischer rats fed a normal diet (controls, N=12) or a diet containing strontium ranelate (900mg/kg/day; N=12) for a period of 104weeks. The L(5) vertebra was scanned by μCT and a morphological analysis of the vertebral body was performed. Subsequently, those μCT data were the basis of FE models with added virtual endcaps that simulated axial compression tests. The FE models were solved with the vertebral bodies only and repeated with the vertebral processes intact. In the initial stages, the intrinsic bone properties were kept constant between the control and the treated animals in order to independently study the impact of microarchitectural changes on bone strength. Morphological data indicated a significant improvement in bone microarchitecture associated with strontium ranelate compared to controls, including a 40% (p<0.01) higher trabecular thickness, a 28% (p<0.01) higher cortical thickness, and no significant change in the number of trabeculae (p=0.56). The poor correlation of bone strontium content against bone volume fraction (BV/TV) (R(2)=0.013, p=0.74) and BMD (R(2)=0.153, p=0.23) indicated that the morphological data were not biased by the presence of strontium in bone. The FE simulations demonstrated a 22% (p<0.01) increase of stiffness and 29% (p<0.01) increase in strength compared to controls. The magnitudes were greater, but the relative differences were similar when the entire intact vertebra was modeled compared to the vertebral body alone. Adjusting the FE models to account for differences in intrinsic bone tissue quality between control and treated animals resulted in an even higher bone strength with strontium ranelate. Furthermore, load transfer in strontium ranelate treated animals shifted from an equal distribution between cortical and trabecular compartments to more load being supported by the trabecular bone (a shift of 8%, p<0.02). Tissue-level stresses were reduced on average (-7%, p<0.01) and more homogeneously distributed. Together, these findings indicated that, independently from bone strontium content, microarchitectural adaptations played a major role in the increased bone strength associated with strontium ranelate exposure and that the changes in load distribution resulted in patterns that were more favorable to resisting fracture.

Use of strontium as a treatment method for osteoporosis

Given its increasing incidence and serious complications, osteoporosis requires safe and effective long-term treatment. Strontium ranelate (SR), a new anti-osteoporotic treatment with a unique mode of action, has been investigated in the SOTI (Spinal Osteoporosis Therapeutic Intervention) and the TROPOS (Treatment of Peripheral Osteoporosis) trials, two major 3-year multinational placebo-controlled phase 3 randomized clinical trials. Unlike antiresorptive agents, SR produced steady and significant bone mineral density increases that correlated directly with decreases in vertebral and hip fracture risk. The safety profile of SR was almost similar to placebo in both trials. A slight but significant increased risk of thromboembolism events was noted from the pooled phase 3 studies data. However, this increased was not found in a large retrospective observational study. Thus, SR demonstrates broad spectrum safety and efficacy in reducing the risks of both vertebral and nonvertebral (including hip) fractures in a wide variety of patients, and should be considered as a first-line option to treat women at risk of osteoporotic fractures, whatever their age, the severity of the disease, and their risk factors.

Strontium ranelate: a look back at its use for osteoporosis

IMPORTANCE OF THE FIELD

Osteoporosis is now considered a major health problem in all developed and in most developing (non-African) countries.

AREAS COVERED IN THIS REVIEW

In this review, we provide an extensive literature survey (MEDLINE, PubMed, Cochrane Controlled Register), for articles dealing with osteoporosis management and/or strontium ranelate, from 1920 to 2010.

WHAT THE READER WILL GAIN

The objective is to provide an extensive, unbiased assessment of the available data allowing strontium ranelate to be placed in perspective with other anti-osteoporosis treatments.

TAKE HOME MESSAGE

Owing to a positive benefit-to-risk ratio, strontium ranelate may now be considered a first-line treatment in the management of osteoporosis.

Treatment of Postmenopausal Osteoporosis: Focus on Strontium Ranelate

Given its increasing incidence and serious complications, osteoporosis requires safe and effective long-term treatment. Strontium ranelate (SR), a new anti-osteoporotic treatment with a unique mode of action, has been investigated in the Spinal Osteoporosis Therapeutic Intervention (SOTI) and the Treatment Of Peripheral OSteoporosis (TROPOS) trials, two major 3-year multinational placebo-controlled Phase III randomized clinical trials. In SOTI, SR treatment reduced the risk of vertebral fracture by 41% (20.9% vs. 32.8%, P < 0.001); in TROPOS, it reduced the risk of non-vertebral fracture by 16% (11.2% vs. 12.9%, P = 0.04), and the risk of hip fracture in patients at high risk by 36% (4.3% vs. 6.4%, P = 0.046). Also SR has been shown to decrease the risk of vertebral fracture after 4 years of treatment and the risk of nonvertebral fracture after 5 years. Also it demonstrated for high risk patients a significant decrease of the risk of hip fractures (–43%) after 5 years of treatment. Unlike antiresorptive agents, SR produced steady and significant BMD increases that correlated directly with decreases in vertebral and hip fracture risk. Preplanned analysis of the pooled dataset from SOTI and TROPOS showed that SR was effective whether or not patients had key risk factors for fractures at baseline. SR was also effective in patients with osteopenia and younger postmenopausal patients aged 50–65 years. It was also effective for preventing both vertebral and nonvertebral fractures in the elderly (>80 years). Also, SR significantly attenuated height loss and decreased back pain. Finally long-term follow-up showed that BMD gains were maintained through a 8 year-period with maintaining the incidence of fracture between the first 3 years and the last 3 years of treatment. The safety profile of SR was almost similar to placebo in both trials. A slight but significant increased risk of thromboembolism events was noted from the pooled phase III studies data. However this increased was not found in a large retrospective observational study. Thus, SR demonstrates broad spectrum safety and efficacy in reducing the risks of both vertebral and non-vertebral (including hip) fractures in a wide variety of patients, and should be considered as a first-line option to treat women at risk of osteoporotic fractures, whatever their age, the severity of the disease, and their risk factors.

A FRAX® model for the assessment of fracture probability in Belgium

A country-specific FRAX® model was developed from the epidemiology of fracture and death in Belgium. Fracture probabilities were identified that corresponded to currently accepted reimbursement thresholds.

INTRODUCTION

The objective of this study was to evaluate a Belgian version of the WHO fracture risk assessment (FRAX®) tool to compute 10-year probabilities of osteoporotic fracture in men and women. A particular aim was to determine fracture probabilities that corresponded to the reimbursement policy for the management of osteoporosis in Belgium and the clinical scenarios that gave equivalent fracture probabilities.

METHODS

Fracture probabilities were computed from published data on the fracture and death hazards in Belgium. Probabilities took account of age, sex, the presence of clinical risk factors and femoral neck bone mineral density (BMD). Fracture probabilities were determined that were equivalent to intervention (reimbursement) thresholds currently used in Belgium.

RESULTS

Fracture probability increased with age, lower BMI, decreasing BMD T-score and all clinical risk factors used alone or combined. The 10-year probabilities of a major osteoporosis-related fracture that corresponded to current reimbursement guidelines ranged from approximately 7.5% at the age of 50 years to 26% at the age of 80 years where a prior fragility fracture was used as an intervention threshold. For women at the threshold of osteoporosis (femoral neck T-score = -2.5 SD), the respective probabilities ranged from 7.4% to 15%. Several combinations of risk-factor profiles were identified that gave similar or higher fracture probabilities than those currently accepted for reimbursement in Belgium.

CONCLUSIONS

The FRAX® tool has been used to identify possible thresholds for therapeutic intervention in Belgium, based on equivalence of risk with current guidelines. The FRAX® model supports a shift from the current DXA-based intervention strategy, towards a strategy based on fracture probability of a major osteoporotic fracture that in turn may improve identification of patients at increased fracture risk. The approach will need to be supported by health economic analyses.

Strontium ranelate: a review of its use in the treatment of postmenopausal osteoporosis

This is a review of the pharmacology of strontium ranelate (Protelos, Protos, Protaxos, Bivalos, Osseor), and its efficacy and tolerability in the treatment of patients with postmenopausal osteoporosis. Strontium ranelate is a divalent strontium salt of ranelic acid that is capable of increasing bone formation and reducing bone resorption, thereby uncoupling and rebalancing bone turnover in favour of bone formation. The drug is effective in reducing the risk of fractures, including both vertebral and nonvertebral fractures, in patients with postmenopausal osteoporosis, according to data from two large, double-blind, placebo-controlled, multicentre trials of 5 years' duration, and reduced the risk of hip fracture in high-risk patients in a post hoc analysis of one trial. Moreover, data from patients who continued to receive the drug during the 3-year extension phases of these trials indicate that strontium ranelate continues to provide protection against new vertebral fractures and nonvertebral fractures for up to 8 years of therapy. It also improves bone mineral density at numerous sites and both increases markers of bone formation and decreases markers of bone resorption. Strontium ranelate is administered orally as a suspension and is generally well tolerated. The nature of adverse events was generally similar regardless of treatment duration in clinical trials, with the most commonly reported being nausea and diarrhoea over 5 years of treatment, and memory loss and diarrhoea during longer-term treatment. Although an increased risk of venous thromboembolism was associated with strontium ranelate relative to placebo over 5 years of treatment in a pooled analysis of clinical trials, postmarketing data have not confirmed this finding. Overall, the clinical data available suggest that strontium ranelate is an effective and generally well tolerated option for the first-line treatment of postmenopausal osteoporosis.

Evidence-based guidelines for the pharmacological treatment of postmenopausal osteoporosis: a consensus document by the Belgian Bone Club

Several drugs are available for the management of postmenopausal osteoporosis. This may, in daily practice, confuse the clinician. This manuscript offers an evidence-based update of previous treatment guidelines, with a critical assessment of the currently available efficacy data on all new chemical entities which were granted a marketing authorization. Osteoporosis is widely recognized as a major public health concern. The availability of new therapeutic agents makes clinical decision-making in osteoporosis more complex. Nation-specific guidelines are needed to take into consideration the specificities of each and every health care environment. The present manuscript is the result of a National Consensus, based on a systematic review and a critical appraisal of the currently available literature. It offers an evidence-based update of previous treatment guidelines, with the aim of providing clinicians with an unbiased assessment of osteoporosis treatment effect.

Strontium ranelate decreases receptor activator of nuclear factor-ΚB ligand-induced osteoclastic differentiation in vitro: involvement of the calcium-sensing receptor

Strontium ranelate exerts both an anticatabolic and an anabolic effect on bone cells. To further investigate the mechanism by which strontium ranelate inhibits bone resorption, the effects of varying concentrations of Sr(o)(2+) on osteoclastic differentiation were studied using RAW 264.7 cells and peripheral blood monocytic cells (PBMCs). We report that increasing concentrations of Sr(o)(2+) down-regulate osteoclastic differentiation and tartrate-resistant acid phosphatase activity, leading to inhibition of bone resorption (-48% when PBMCs were cultured for 14 days in the presence of 2 mM Sr(o)(2+)). Using a dominant-negative form of the calcium-sensing receptor (CaR) and a small interfering RNA approach, we provide evidences that the inhibition of osteoclast differentiation by Sr(o)(2+) is mediated by stimulation of the CaR. Moreover, our results suggest that the effects of Sr(o)(2+) on osteoclasts are, at least in part, mediated by inhibition of the receptor activator of nuclear factor-κB ligand (RANKL)-induced nuclear translocation of nuclear factor-κB and activator protein-1 in the early stages of osteoclastic differentiation. In conclusion, our data indicate that Sr(2+) directly inhibits the formation of mature osteoclasts through down-regulation of RANKL-induced osteoclast differentiation and decreases osteoclast differentiation through the activation of the CaR.

Current, new and future treatments of osteoporosis

Osteoporosis as a common chronic disease is challenging human health. Although different therapeutic options are routinely used for prevention/treatment of osteoporosis, their side effects and benefits are under question. Increasing our knowledge about signaling pathways in bone and osteocytes as well as osteoblasts and osteoclasts will help us in designing new therapeutic modalities for osteoporosis. In the present study, all new therapeutic measures of osteoporosis have been reviewed. For this purpose, search engines like Pubmed, Web of Science, Scopus, Google Scholar were searched and all relevant articles were found. The study was limited to the year 1998-2010. Bisphosphonates are the cornerstone of osteoporosis treatment, but there are not enough relevant studies that investigated their equivalencies in comparison with each other or the other medications. Therefore, medication selection is empirical and subjective. Furthermore, no eminent study has compared certain combinations. There are new hopes for treatment of osteoporosis, which are more specific with less harm. Our results show that new and emerging therapies are more potent and target specified which more individualize osteoporosis treatment; however, more investigations on their safety and efficacy in comparison with current medications are highly recommended.

Strontium ranelate: an effective solution for diverse fracture risks

Osteoporosis is listed by the WHO among the ten most frequent and socio-economically important, chronic diseases of mankind. The term osteoporosis however comprises a number of different pathophysiological conditions and clinical situations of weakened bones with increased risk of fragility fractures. A modern anti-osteoporotic drug should provide qualified study results proving therapeutic efficacy over this broad range of daily clinical appearances of osteoporosis. The decision for treatment in the individual patients depends no longer only on bone mineral density. Today, the major criterion for decision making is the prospective 10-year risk for fractures. Since this risk is calculated on the basis of age, sex, bone mineral density, prevalent fractures, and a number of other contributing risk factors (Kanis et al., Osteoporos Int 12:989-995, 2001; Kanis et al., Osteoporos Int 19:385-397, 2008), it seems to be of interest to have a look whether the fracture-reducing potency of a drug is influenced by these risk factors. The purpose of this review is to analyze whether the fracture-reducing efficacy of strontium ranelate in patients with osteoporosis can be achieved independently of sex, etiology of osteoporosis, and the major diagnostically relevant risk factors.

Addressing the age-related needs of osteoporotic patients with strontium ranelate

Osteoporotic fractures are associated with significant morbidity and mortality with an enormous impact on society and the lives of affected individuals. Age and menopause are the two main risk factors for osteoporosis, and women therefore need to be particularly concerned about bone loss at this time. In addition to suffering fracture-associated morbidity, women with prior fractures have an increased risk of future fractures. Young postmenopausal women who have experienced a fragility fracture therefore face a lifetime of fracture risk. The burden of fractures increases with advancing age, and bone mineral density declines, with women over the age of 80 years having the highest risk of fracture because of their high prevalence of osteoporosis and an increased likelihood of falls. A number of antiosteoporotic agents are available for the treatment of postmenopausal women including bisphosphonates, raloxifene, teriparatide, and strontium ranelate. For osteoporotic drugs to be beneficial in reducing the burden of fractures, they need to be effective against fracture in all age groups of postmenopausal women. With its dual mode of action, strontium ranelate is the first agent with proven early and sustained antifracture efficacy in all age groups including young postmenopausal women and those over 80 years. Evidence is now available to show that all women, including the elderly, can benefit from treatment to prevent further bone loss and restore lost bone to decrease the risk of further fractures. By implementing procedures to identify those at greatest risk and initiate safe and effective treatments, physicians can significantly improve patients' quality of life.

Osteoporosis: disease severity and consequent fracture management

Osteoporosis is a systemic skeletal disease responsible for the high incidence of fractures in older subjects, particularly in postmenopausal women. The increasing prevalence with population ageing and prolonged life expectancy raises the rates of associated morbidity, loss of independence, and mortality. BMD and previous fracture history are two main risk factors associated with osteoporosis such that the presence of prior fractures can predict future fractures. Strontium ranelate is an agent developed for the management of postmenopausal osteoporosis, demonstrated to reduce vertebral, nonvertebral, major nonvertebral, and hip fractures. It has been demonstrated to be effective for a broad spectrum of patients, including women with osteopenia, osteoporosis, and severe disease.