Bisphosphonates for postmenopausal osteoporosis: determining duration of treatment

Management of insufficiency fractures associated with long-term bisphosphonate therapy in a cat

Case summary

A 10-year-old spayed female domestic medium hair cat presented after sustaining atraumatic insufficiency fractures of the right calcaneus and the left tibia approximately 6 weeks apart. Chronic alendronate therapy had been ongoing for 9 years for the management of previously diagnosed idiopathic hypercalcemia. The right calcaneal fracture was managed non-operatively due to minimal functional impairment. The left tibial fracture was managed via open reduction and internal fixation with orthogonal plating. Alendronate therapy was discontinued at the time of the fracture repair with prednisolone being used to manage the hypercalcemia. Despite rapid clinical improvement, the tibial fracture had a protracted healing course, with clinical union only being achieved 22 weeks postoperatively. At 17 months postoperatively, the idiopathic hypercalcemia remained well controlled. Gait assessment, orthopedic examination and orthogonal radiographs performed at this time revealed resolution of left pelvic limb lameness, a normal orthopedic examination of the left pelvic limb and no evidence of implant-associated complications. Monitoring is ongoing but at the time of publication, no further fractures have occurred.

Relevance and novel information

As reported in humans, this case report gathers evidence of associations between bisphosphonate treatment and the occurrence of insufficiency fractures in cats, and provides evidence that stress reactions may precede their development. If bisphosphonate therapy is utilized in the long term, serial radiographic monitoring for signs of impending fracture may be warranted. Fracture repair can be successful in cats that have received long-term bisphosphonate therapy, but delayed healing should be anticipated and implant choices made accordingly.

Long-term pretreatment with alendronate inhibits calvarial defect healing in an osteoporotic rat model

INTRODUCTION

This study aimed to observe the effects of long-term alendronate pretreatment on the healing of osteoporotic calvarial defects, and further investigate the effect of alendronate combined with once-weekly parathyroid hormone following 12 weeks of alendronate treatment in ovariectomized rats.

MATERIALS AND METHODS

Thirty 3-month-old female rats were ovariectomized, and 24 rats received alendronate for 12 weeks. Then, a critical defect was created in the calvaria of all animals. Immediately after osteotomy, the animals received one of five treatments for 8 weeks: (1) continuation of vehicle (group E), (2) alendronate followed by vehicle (group A), (3) continuation of alendronate (group B), (4) alendronate followed by once-weekly parathyroid hormone alone (group C), or (5) continuation of alendronate combined with once-weekly parathyroid hormone (group D). Calvarial defect healing was assessed using dual-energy X-ray absorptiometry, micro-computed tomography, histology, and sequential fluorescence labeling.

RESULTS

Group E showed a significantly higher volume of newly formed bone than groups A, B, C, and D. Evidence of new dense bone formation in group E was observed histologically. In addition, the immunohistochemical expression of runt-related transcription factor 2 was increased in group E but inhibited in groups A, B, C, and D. Sequential immunofluorescence also showed inhibited mineral apposition in groups A, B, C, and D compared with group E.

CONCLUSION

The present study shows that long-term pretreatment with alendronate inhibited calvarial defect healing in osteoporotic rats, and this effect could not be reversed by stopping alendronate, switching to parathyroid hormone, or combining with once-weekly parathyroid hormone.

Bilateral patellar fractures and increased cortical bone thickness associated with long-term oral alendronate treatment in a cat

Case summary

A 14-year-old cat presented with bilateral patellar fractures and radiographically thickened tibial cortices. This cat had been treated with alendronate for 8 years prior to presentation. To remove the subjectivity of the radiographic evaluation, tibial radiographs from 35 apparently healthy geriatric cats were used for comparison. Cortical and diaphyseal thickness were measured at the proximal and distal thirds of the tibia. Our cat had increased cortical bone thickness compared to that of the control cats.

Relevance and novel information

Treatment with bisphosphonates can lead to brittle bones and fractures after prolonged use in humans. This is the first description of fractures and cortical bone changes that may have been associated with prolonged bisphosphonate use in a cat. Radiographic measurements of cortical bone thickness may identify cats that are at increased risk for bone pathology secondary to prolonged alendronate use.

Incorporating bazedoxifene into the treatment paradigm for postmenopausal osteoporosis in Japan

The incidence of osteoporosis-related fractures in Asian countries is steadily increasing. Optimizing osteoporosis treatment is especially important in Japan, where the rate of aging is increasing rapidlyelderly population is increasing rapidly and life expectancy is among the longest in the world. There are several therapies currently available in Japan for the treatment of postmenopausal osteoporosis, each with a unique risk/benefit profile. A novel selective estrogen receptor modulator, bazedoxifene (BZA), was recently approved for the treatment of postmenopausal osteoporosis in Japan. Results from a 2-year, phase 2 trial in postmenopausal Japanese women showed that BZA significantly improved lumbar spine and total hip bone mineral density compared with placebo, while maintaining endometrial and breast safety, consistent with results from 2 global, phase 3 trials including a 2-year osteoporosis prevention study and a 3-year osteoporosis treatment study. In the pivotal 3-year treatment study, BZA significantly reduced the incidence of new vertebral fractures compared with placebo; in a post hoc analysis of a subgroup of women at higher risk of fractures, BZA significantly reduced the risk of nonvertebral fractures compared with placebo and raloxifene. A 2-year extension of the 3-year treatment study demonstrated the sustained efficacy of BZA over 5 years of treatment. BZA was generally safe and well tolerated in these studies. In a "super-aging" society such as Japan, long-term treatment for postmenopausal osteoporosis is a considerable need. BZA may be considered as a first choice for younger women anticipating long-term treatment, and also an appropriate option for older women who are unable or unwilling to take bisphosphonates.

Long-term effects of alendronate on fracture healing and bone remodeling of femoral shaft in ovariectomized rats

AIM

To investigate the long-term effects of alendronate (Aln), a widely used oral bisphosphonate, on fracture healing and bone remodeling in ovariectomized rats.

METHODS

Adult female SD rats underwent ovariectomy, and then bilateral femoral osteotomy at 12 weeks post-ovariectomy. From d 2 post-ovariectomy, the animals were divided into 3 groups, and treated with Aln (3 mg·kg(-1)·d(-1), po) for 28 weeks (Aln/Aln), Aln for 12 weeks and saline for 16 weeks (Aln/Saline) or saline for 28 weeks (Saline/Saline). At 6 and 16 weeks post-fracture, the fracture calluses were examined with X-ray radiography, and biomechanical testing and histological analysis were performed. The calluses were labeled with tetracycline and calcein to evaluate the mineral apposition rate (MAR).

RESULTS

The fracture line was less distinct in the 2 Aln-treated groups at 6 weeks post-fracture, and disappeared in all the 3 groups at 16 weeks post-fracture. The size of the callus and radiographic density of the femora in the Aln/Aln group were the highest among the 3 groups at 6 and 16 weeks post-fracture. Similar results were observed in the ultimate load at failure and energy absorption. However, the treatment with Aln delayed endochondral ossification of the callus, and significantly increased the total sagittal-sectional area, percentage callus area and callus thickness, and decreased the MAR at 6 and 16 weeks post-fracture.

CONCLUSION

In the ovariectomized rat model, Aln is beneficial for the mechanical properties of the callus, but delays callus remodeling by suppressing the remodeling of woven bone into lamellar bone.

Bisphosphonates and nonhealing femoral fractures: analysis of the FDA Adverse Event Reporting System (FAERS) and international safety efforts: a systematic review from the Research on Adverse Drug Events And Reports (RADAR) project

BACKGROUND

In the United States, hip fracture rates have declined by 30% coincident with bisphosphonate use. However, bisphosphonates are associated with sporadic cases of atypical femoral fracture. Atypical femoral fractures are usually atraumatic, may be bilateral, are occasionally preceded by prodromal thigh pain, and may have delayed fracture-healing. This study assessed the occurrence of bisphosphonate-associated nonhealing femoral fractures through a review of data from the U.S. FDA (Food and Drug Administration) Adverse Event Reporting System (FAERS) (1996 to 2011), published case reports, and international safety efforts.

METHODS

We analyzed the FAERS database with use of the proportional reporting ratio (PRR) and empiric Bayesian geometric mean (EBGM) techniques to assess whether a safety signal existed. Additionally, we conducted a systematic literature review (1990 to February 2012).

RESULTS

The analysis of the FAERS database indicated a PRR of 4.51 (95% confidence interval [CI], 3.44 to 5.92) for bisphosphonate use and nonhealing femoral fractures. Most cases (n = 317) were attributed to use of alendronate (PRR = 3.32; 95% CI, 2.71 to 4.17). In 2008, international safety agencies issued warnings and required label changes. In 2010, the FDA issued a safety notification, and the American Society for Bone and Mineral Research (ASBMR) issued recommendations about bisphosphonate-associated atypical femoral fractures.

CONCLUSIONS

Nonhealing femoral fractures are unusual adverse drug reactions associated with bisphosphonate use, as up to 26% of published cases of atypical femoral fractures exhibited delayed healing or nonhealing.

Fourier transform infrared imaging of femoral neck bone: reduced heterogeneity of mineral-to-matrix and carbonate-to-phosphate and more variable crystallinity in treatment-naive fracture cases compared with fracture-free controls

After the age of 60 years, hip fracture risk strongly increases, but only a fifth of this increase is attributable to reduced bone mineral density (BMD, measured clinically). Changes in bone quality, specifically bone composition as measured by Fourier transform infrared spectroscopic imaging (FTIRI), also contribute to fracture risk. Here, FTIRI was applied to study the femoral neck and provide spatially derived information on its mineral and matrix properties in age-matched fractured and nonfractured bones. Whole femoral neck cross sections, divided into quadrants along the neck's axis, from 10 women with hip fracture and 10 cadaveric controls were studied using FTIRI and micro-computed tomography. Although 3-dimensional micro-CT bone mineral densities were similar, the mineral-to-matrix ratio was reduced in the cases of hip fracture, confirming previous reports. New findings were that the FTIRI microscopic variation (heterogeneity) of the mineral-to-matrix ratio was substantially reduced in the fracture group as was the heterogeneity of the carbonate-to-phosphate ratio. Conversely, the heterogeneity of crystallinity was increased. Increased variation of crystallinity was statistically associated with reduced variation of the carbonate-to-phosphate ratio. Anatomical variation in these properties between the different femoral neck quadrants was reduced in the fracture group compared with controls. Although our treatment-naive patients had reduced rather than increased bending resistance, these changes in heterogeneity associated with hip fracture are in another way comparable to the effects of experimental bisphosphonate therapy, which decreases heterogeneity and other indicators of bone's toughness as a material.

Evidence of sustained vertebral and nonvertebral antifracture efficacy with ibandronate therapy: a systematic review

BACKGROUND

The antifracture efficacy of ibandronate at vertebral and nonvertebral sites was assessed.

METHODS

A literature review of randomized phase III clinical trials, meta-analyses or observational studies that reported fracture endpoints or surrogate markers, and compared ibandronate with placebo or an active comparator.

RESULTS

In a phase III study, 2.5 mg daily oral ibandronate reduced the incidence of new vertebral fractures versus placebo and the relative risk reduction (RRR) was sustained over 3 years (62%; p = 0.0001). In two bridging studies, oral ibandronate 150 mg once monthly and 3 mg quarterly intravenous (i.v.) were superior to oral 2.5 mg daily in producing bone mineral density (BMD) increases at all sites over 2 years (p < 0.05). These improvements were sustained over 5 years. In meta-analyses of pivotal ibandronate studies, doses equivalent to annual cumulative exposure (ACE) ≥ 10.8 mg (including 150 mg once monthly and 3 mg quarterly i.v.) significantly reduced the incidence of nonvertebral fractures versus placebo or ACE 5.5 mg (2.5 mg daily) (RRR 29.9% and 38%, respectively; p < 0.05). Therefore, prevention of nonvertebral fractures was found in all patients with the commercially available highest doses, and not only in high-risk patients as observed in randomized clinical trials with lower doses. Finally, a 12-month, observational study of claims databases reported comparable rates of nonvertebral fractures and a statistically significantly lower rate of vertebral fractures (p < 0.01) with ibandronate versus weekly bisphosphonates.

CONCLUSION

A large body of evidence suggests that ibandronate has sustained vertebral and nonvertebral antifracture efficacy in women with postmenopausal osteoporosis.

Long-term administration of quarterly IV ibandronate is effective and well tolerated in postmenopausal osteoporosis: 5-year data from the DIVA study long-term extension

Long-term bone mineral density (BMD) gains, bone marker levels, and safety of 3 mg quarterly intravenous (IV) ibandronate were studied in this 3-year extension to the Dosing IntraVenous Administration (DIVA) trial. Quarterly IV ibandronate consistently increased lumbar spine bone mineral density measured with dual-energy X-ray absorptiometry (DXA-BMD) over 5 years (8.1%) and was well tolerated in women with postmenopausal osteoporosis.

INTRODUCTION

Treatment with IV ibandronate regimens, 2 mg bimonthly and 3 mg quarterly, has been studied for up to 5 years in a long-term extension (LTE) to the 2-year DIVA trial.

METHODS

DIVA LTE is an open-label extension to a 2-year randomized, double-blind, double-dummy, noninferiority, phase III study (DIVA core). DIVA LTE involved postmenopausal women who had completed 2 years of DIVA core, comparing daily oral and IV ibandronate (≥75% adherence with IV ibandronate in year 2 of DIVA). Patients previously treated with 2 mg bimonthly or 3 mg quarterly IV ibandronate continued on the same regimen; patients who had received 2.5 mg daily oral ibandronate and placebo IV in DIVA core were switched to IV ibandronate.

RESULTS

Pooled analysis of 497 intent-to-treat (ITT) patients receiving IV ibandronate from DIVA core baseline showed consistent increases over 5 years in lumbar spine DXA-BMD (8.4% [95% confidence interval (CI) = 7.5, 9.3] with 2 mg bimonthly and 8.1% [95% CI = 7.2, 8.9] with 3 mg quarterly). Three-year data relative to DIVA LTE baseline in the full ITT population (756 patients randomized or reallocated from DIVA, including those previously on daily treatment) showed maintenance of DXA-BMD gains from DIVA core with further gains in lumbar spine DXA-BMD. These benefits are supported by sustained reductions in markers of bone metabolism. No tolerability concerns or new safety signals were observed.

CONCLUSIONS

Treatment with IV ibandronate 2 mg bimonthly or 3 mg quarterly is effective and well tolerated for up to 5 years in women with postmenopausal osteoporosis.

Bisphosphonate prescribing, persistence and cumulative exposure in Ontario, Canada

We studied new users of oral bisphosphonates and found that less than half persisted with therapy for 2 years, and interruptions in use were common. During a median observation period of 4.7 years, 10% of patients filled only a single prescription, 37% switched therapies and median cumulative exposure was 2.2 years.

INTRODUCTION

We sought to describe bisphosphonate prescribing, persistence and cumulative exposure among seniors in Ontario, Canada.

METHODS

We used Ontario Drug Benefit pharmacy claims to identify residents aged ≥ 66 years who initiated oral bisphosphonate therapy between April 1996 and March 2009. The first date of bisphosphonate dispensing was considered the index date. Persistence with therapy was defined as continuous treatment with no interruption exceeding 60 days. We examined persistence with therapy and the number of extended gaps (>60 days) between prescriptions over time periods ranging from 1 to 9 years. We also identified the proportion of patients filling only a single prescription and switching to a different bisphosphonate, and calculated the median days of exposure irrespective of gaps in therapy.

RESULTS

A total of 451,113 eligible new bisphosphonate users were identified: mean age = 75.6 years (SD = 6.9), 84% female, and median follow-up length = 4.7 years. Persistence with therapy declined from 63% at 1 year to 46% at 2 years and 12% at 9 years. Among those with at least 5 years of follow-up (n = 213,029), 61% had one or more extended gaps in bisphosphonate therapy. Overall, 10% of patients filled only a single prescription, 37% switched to a different bisphosphonate and the median exposure was 2.2 years.

CONCLUSION

Less than half of patients persisted with bisphosphonate therapy for 2 years and interruptions in therapy were common, with most patients experiencing two or more >60-day gaps in therapy. Interventions are needed to improve persistence with bisphosphonate therapy and reduce the frequency of gaps in treatment.

Individualizing osteoporosis therapy

Guidelines for osteoporosis treatment are available; however, these guidelines suggest when to treat patients, without specific recommendations on what drugs to prescribe in various situations. Choice of osteoporosis therapy should be individualized based on consideration of the efficacy, safety, cost, convenience (i.e., dosing regimen and delivery), and other non-osteoporosis-related benefits associated with each agent. Bisphosphonates, administered orally or intravenously, should be considered first-line therapy, particularly in older patients, owing to their efficacy across multiple skeletal sites; however, there are potential short- and long-term safety concerns. Selective estrogen receptor modulators should be considered for younger postmenopausal women at greater risk for vertebral than hip fractures or as second-line therapy in women who cannot tolerate first-line therapies. Low-dose hormone therapy may be appropriate as prevention in women with menopausal symptoms at lower fracture risk. Calcitonin, with its relatively benign safety profile, may be appropriate for elderly women who may have difficulty following the complex dosing schedules of oral bisphosphonates. Anabolic therapies such as teriparatide should be considered for high-risk patients. Strontium ranelate (approved outside of North America), with both anabolic and antiresorptive properties, may be appropriate for women who cannot tolerate or are unable to take bisphosphonates. Denosumab is a monoclonal antibody appropriate for women at high fracture risk or who have failed other osteoporosis therapies, and may be considered in patients with renal insufficiency. It will be important to incorporate newer agents (e.g., bazedoxifene, tissue selective estrogen complex) into this individualized treatment paradigm to optimize clinical outcomes in patients with osteoporosis.

Use of bisphosphonate and risk of atrial fibrillation in older women with osteoporosis

Concerns have been raised among clinicians and patients whether or not bisphosphonates increase the risk of atrial fibrillation. In this large cohort study, increased risk of atrial fibrillation was not found to be associated with bisphosphonate. In fact, bisphosphonate even showed a protective effect against cardiac arrhythmia compared to other osteoporosis medications.

INTRODUCTION

Increased risk of atrial fibrillation among bisphosphonate users has been reported; however, the results from these studies are controversial. The purpose of this study was to evaluate the risk of atrial fibrillation associated with bisphosphonate use in older women.

METHODS

We used the Korean Health Insurance Review and Assessment Service claims database from May 1, 2005 to June 30, 2006. Retrospective cohort analysis was conducted on women 65 years or older with newly diagnosed cases of osteoporosis (ICD 10 code: M80, M81) who had not previously taken any medications for osteoporosis. Bisphosphonate-exposed and non-exposed patients were followed until they were either diagnosed with atrial fibrillation (ICD 10 code: I48) or until the end of the study. The Cox proportional hazards model was used to calculate hazard ratios and the 95% confidence intervals.

RESULTS

Atrial fibrillation was reported in 626 of the 120,319 patients (0.52%) treated with bisphosphonates and 66 of 9,863 patients (0.67%) treated with other osteoporosis medications. Overall hazard ratio for developing atrial fibrillation in the bisphosphonate-treated group was 0.52 (95% CIs, 0.29-0.91). In patients with a medication possession ratio greater than 0.7, the hazard ratio was lower (HR 0.41, 95% CIs 0.23-0.75). In the subgroup analysis, alendronate showed a statistically significant protective effect against the risk of atrial fibrillation with a hazard ratio of 0.75 (95% CI, 0.58-0.97).

CONCLUSION

Among older Korean women with osteoporosis, bisphosphonate was found to have a protective effect against atrial fibrillation.

Fracture risk associated with continuation versus discontinuation of bisphosphonates after 5 years of therapy in patients with primary osteoporosis: a systematic review and meta-analysis

Purpose:

The risks and benefits of continuing bisphosphonate therapy beyond 5 years in patients with primary osteoporosis have not been well established.

Methods:

We searched MedLine, EMBase, CENTRAL, CINAHL, and AgeLine prior to February 2010. Bibliographies were also searched and experts in the field contacted. The ProQuest Dissertations and Theses database and relevant conference proceedings were searched to identify unpublished or ongoing studies. Two authors independently reviewed search results. Randomized controlled trials and comparative nonrandomized controlled trials examining post-menopausal women or men ≥50 years of age with primary osteoporosis assigned to continue versus discontinue bisphosphonate therapy after ≥5 years of therapy were included. Of 1188 identified articles, three studies (n = 1443) met criteria for inclusion in data synthesis. Data were extracted and risk of bias assessed by two independent reviewers using predefined criteria.

Results:

No statistically significant association was found between fracture incidence and the discontinuation of therapy beyond 5 years for any type of fracture: clinical nonvertebral fracture (relative risk [RR] = 0.97; 95% confidence interval [CI] 0.77–1.23), clinical vertebral fracture (RR = 0.61; 95% CI 0.32–1.19), or morphometric vertebral fracture (RR = 0.90; 95% CI 0.5–1.64). No differences in adverse events were identified between the two groups.

Conclusion:

We found no significant difference in fracture risk or adverse events between postmenopausal women with primary osteoporosis who continued bisphosphonate therapy versus those who discontinued bisphosphonate therapy after 5 years of treatment. However, given the small number and limited quality of available studies, no firm conclusions or recommendations can be made.

Measuring and improving adherence to osteoporosis pharmacotherapy

PURPOSE OF REVIEW

Osteoporosis is a major public health issue resulting in considerable fracture-related morbidity. Although effective treatment exists, adherence to osteoporosis pharmacotherapy is suboptimal and linked to reduced drug effectiveness. In this paper, we review methods of measuring and improving adherence to osteoporosis pharmacotherapy.

RECENT FINDINGS

Most patients will stop osteoporosis pharmacotherapy, yet the majority who discontinue will reinitiate treatment after an extended gap. The key to improving adherence to osteoporosis pharmacotherapy is to reduce the number and length of gaps in treatment. Multifaceted and individualized interventions may help to improve adherence. New strategies aimed at identifying patients likely to stop therapy may also facilitate the development of targeted interventions.

SUMMARY

Adherence to osteoporosis pharmacotherapy is suboptimal with short periods of persistence and lengthy gaps in therapy. Regular communication regarding the importance of continued therapy is critical. More research to help identify risk profiles of patients likely to become nonadherent, targeted multifaceted interventions to maximize adherence to therapy, and data to support when patients may safely consider a physician directed drug holiday is needed.

Methods to examine the impact of compliance to osteoporosis pharmacotherapy on fracture risk: systematic review and recommendations

The objective of this study was to review the methods of prior studies that estimate the association between compliance to osteoporosis pharmacotherapy on fracture risk, and make recommendations to guide future research. We completed a systematic search of MEDLINE to identify all English language nonexperimental studies that examined the impact of adherence to osteoporosis pharmacotherapy on fracture risk. Studies that measured compliance were eligible and those that only examined persistence were excluded. We summarized the methodology of each study and make recommendations for future research. We identified 14 eligible articles: nine cohort and five nested case-control. Length of baseline (lookback) periods ranged between 3 months and 2 years, with nearly all studies (86%) restricting inclusion to treatment-naïve users. A threshold of 80% was most commonly used to define compliance (n = 10), with few studies providing a more thorough analysis through categorical (n = 3) or continuous (n = 1) measures. All nine cohort studies adjusted for age, sex, prior fracture, and at least one other comorbidity or drug; two cohort studies adjusted for a comorbidity score. Two of the five case-control studies clearly controlled for age, sex, drug exposure, event date and length of follow up. One study considered a theoretical sensitivity analysis to account for potential healthy adherer bias, yet all mentioned limitations related to possible residual confounding. We identify great variability in methods of prior studies that evaluate the impact of compliance to osteoporosis pharmacotherapy on fracture risk, and make recommendations to guide future research.

Case reports: subtrochanteric femoral stress fractures after prolonged alendronate therapy

BACKGROUND

Alendronate is known for its ability to reduce bone loss in osteoporotic and osseous metastatic conditions. Its long-term effects remain unclear although several reports describe cases of proximal femur stress fractures associated with long-term alendronate use.

CASE DESCRIPTION

We report the cases of four women who sustained low-energy subtrochanteric or femoral shaft stress fractures while being on alendronate therapy for more than 5 years. All radiographs showed typical patterns consisting of a transverse fracture line with external cortical bone reaction and medial cortical spike. Alendronate discontinuation along with nonoperative treatment was sufficient for one patient, whereas surgical stabilization was required in three patients.

LITERATURE REVIEW

The side effects of alendronate therapy include osteonecrosis of the jaw, esophageal irritation, and musculoskeletal pain. Several cases of insufficiency femoral fractures associated with prolonged alendronate use have been reported. Their radiographic pattern and clinical presentation are consistent with our observations. Although various hypotheses have been suggested, the physiopathogenesis of these stress fractures is not completely understood.

PURPOSES AND CLINICAL RELEVANCE

Although bisphosphonates play an important role in preventing pathologic fractures in patients with cancer, these subtrochanteric stress fractures associated with prolonged use of alendronate should not be ignored.

Bisphosphonate treatment modifies canine bone mineral and matrix properties and their heterogeneity

Bone loss and alterations in bone quality are major causes leading to bone fragility in postmenopausal women. Although bisphosphonates are well known to reduce bone turnover and prevent bone loss in postmenopausal osteoporosis, their effects on other bone properties are not fully characterized. Changes in bone mineral and matrix properties may contribute to the anti-fracture efficacy observed with bisphosphonate treatments. The aim of this work was to analyze the effect of a 1-year treatment with either alendronate or risedronate, at low and high doses, on spatially resolved bone material and compositional properties that could contribute to the fracture efficacy of these agents. Distal tibias from 30 normal beagles that had been treated daily for 1 year with oral doses of vehicle (Veh), alendronate (Aln) at 0.2 or 1 mg/kg, and risedronate (Ris) at 0.1 or 0.5 mg/kg were analyzed by Fourier Transform Infrared imaging (FTIRI) to assess the changes in both mineral and matrix properties in discrete bone areas. The widths at half maximum of the pixel histograms for each FTIRI parameter were used to assess the heterogeneity of the bone tissue. Aln and Ris increased the mineral content and the collagen maturity mainly in cancellous bone and at the endocortical surface. Significant differences were observed in the mineral content and in the hydroxyapatite crystallinity distribution in bone tissue, which can contribute to reduced ductility and micro-crack accumulation. No significant differences were observed between low and high dose nor between Aln and Ris treatments. These results show that pharmacologic suppression of bone turnover increases the mineral and matrix bone tissue maturity in normal cancellous and endocortical bone areas where bone turnover is higher. These positive effects for decreased fracture risk are also associated with a loss of bone heterogeneity that could be one factor contributing to increased bone tissue brittleness and micro-crack accumulation.

Strategies for treatment to prevent fragility fractures in postmenopausal women

The objective of treatment of osteoporosis is to decrease the risk of fractures in patients at high risk for a first or subsequent fracture. The efficacy of treatment will depend on the efficiency and level of implementation of clinical case finding to select patients at risk, the results of additional investigations, the efficacy, tolerance and safety of medical intervention and the adherence to treatment during follow-up. Each of these steps is critical in treatment in daily practice. Failure to consider one or another step can result in suboptimal fracture prevention or overtreatment. The aim of case finding is to identify patients for treatment, who have disease characteristics of patients in whom fracture prevention has been demonstrated in randomised controlled trials (RCTs). These include patients with a low-trauma hip or vertebral fracture, with a low bone mineral density (BMD) or with a high risk of fracture based on the presence of clinical risk factors (CRFs) for osteoporosis and fractures such as included in the FRAX case-finding algorithm, with or without BMD. Case finding starts clinically, with systematic or opportunistic doctor- and/or patient-driven evaluation for the presence of CRFs, but its implementation is low. Further investigations aim to assess the risk of fracture(s) and to have baseline measurements for the subsequent monitoring of treatment, to exclude diseases that mimic osteoporosis, to identify the cause of osteoporosis and contributory factors and to select the most appropriate treatment. Medical intervention consists of providing information about osteoporosis to the patient, lifestyle advice, optimalisation of calcium intake and vitamin D status, fall prevention to reduce fall risk, correction of reversible contributors to secondary osteoporosis and a wide array of drugs for prevention of a first or subsequent vertebral, hip and non-vertebral, non-hip fracture. Drug treatment is based on manipulation of bone remodelling by inhibiting bone resorption (bisphosphonates, selective oestrogen-receptor modulator (SERMs), calcitonin), stimulating bone formation (parathyroid hormone) or mixed effects (strontium ranelate). Follow-up allows to check tolerance and safety, to optimise adherence and to decide about adequacy of response, duration and switching of therapy.

Progress in osteoporosis and fracture prevention: focus on postmenopausal women

In the past decade, we have witnessed a revolution in osteoporosis diagnosis and therapeutics. This includes enhanced understanding of basic bone biology, recognizing the severe consequences of fractures in terms of morbidity and short-term re-fracture and mortality risk and case finding based on clinical risks, bone mineral density, new imaging approaches, and contributors to secondary osteoporosis. Medical interventions that reduce fracture risk include sufficient calcium and vitamin D together with a wide spectrum of drug therapies (with antiresorptive, anabolic, or mixed effects). Emerging therapeutic options that target molecules of bone metabolism indicate that the next decade should offer even greater promise for further improving our diagnostic and treatment approaches.