Prolonged antiresorptive activity of zoledronate: a randomized, controlled trial

Screening for Osteoporosis to Prevent Fractures: A Systematic Evidence Review for the US Preventive Services Task Force

Importance

Fragility fractures result in significant morbidity.

Objective

To review evidence on osteoporosis screening to inform the US Preventive Services Task Force.

Data Sources

PubMed, Embase, Cochrane Library, and trial registries through January 9, 2024; references, experts, and literature surveillance through July 31, 2024.

Study Selection

Randomized clinical trials (RCTs) and systematic reviews of screening; pharmacotherapy studies for primary osteoporosis; predictive and diagnostic accuracy studies.

Data Extraction and Synthesis

Two reviewers assessed titles/abstracts, full-text articles, study quality, and extracted data; when at least 2 similar studies were available, meta-analyses were conducted.

Main Outcomes and Measures

Hip, clinical vertebral, major osteoporotic, and total fractures; mortality; harms; accuracy.

Results

Three RCTs and 3 systematic reviews reported benefits of screening in older, higher-risk women. Two RCTs used 2-stage screening: Fracture Risk Assessment Tool estimate with bone mineral density (BMD) testing if risk threshold exceeded. One RCT used BMD plus additional tests. Screening was associated with reduced hip (pooled relative risk [RR], 0.83 [95% CI, 0.73-0.93]; 3 RCTs; 42 009 participants) and major osteoporotic fracture (pooled RR, 0.94 [95% CI, 0.88-0.99]; 3 RCTs; 42 009 participants) compared with usual care. Corresponding absolute risk differences were 5 to 6 fewer fractures per 1000 participants screened. The discriminative accuracy of risk assessment instruments to predict fracture or identify osteoporosis varied by instrument and fracture type; most had an area under the curve between 0.60 and 0.80 to predict major osteoporotic fracture, hip fracture, or both. Calibration outcomes were limited. Compared with placebo, bisphosphonates (pooled RR, 0.67 [95% CI, 0.45-1.00]; 6 RCTs; 12 055 participants) and denosumab (RR, 0.60 [95% CI, 0.37-0.97] from the largest RCT [7808 participants]) were associated with reduced hip fractures. Compared with placebo, no statistically significant associations were observed for adverse events.

Conclusions and Relevance

Screening in higher-risk women 65 years or older was associated with a small absolute risk reduction in hip and major fractures compared with usual care. No evidence evaluated screening with BMD alone or screening in men or younger women. Risk assessment instruments, BMD alone, or both have poor to modest discrimination for predicting fracture. Osteoporosis treatment with bisphosphonates or denosumab over several years was associated with fracture reductions and no meaningful increase in adverse events.

Approach to the Pediatric Patient With Glucocorticoid-Induced Osteoporosis

Glucocorticoid (GC) therapy remains the cornerstone of treatment for many conditions of childhood and an important cause of skeletal and endocrine morbidity. Here, we discuss cases that bring to life the most important concepts in the management of pediatric GC-induced osteoporosis (pGIO). Given the wide variety of underlying conditions linked to pGIO, we focus on the fundamental clinical-biological principles that provide a blueprint for management in any clinical context. In so doing, we underscore the importance of longitudinal vertebral fracture phenotyping, how knowledge about the timing and risk of fractures influences monitoring, the role of bone mineral density in pGIO assessments, and the impact of growth-mediated "vertebral body reshaping" after spine fractures on the therapeutic approach. Overall, pGIO management is predicated upon early identification of fractures (including vertebral) in those at risk, and timely intervention when there is limited potential for spontaneous recovery. Even a single, low-trauma long bone or vertebral fracture can signal an osteoporotic event in an at-risk child. The most widely used treatments for pediatric osteoporosis, intravenous bisphosphonates, are currently recommended first-line for the treatment of pGIO. It is recognized, however, that even early identification of bone fragility, combined with timely introduction of the most potent bisphosphonate therapies, may not completely prevent osteoporosis progression in all contexts. Therefore, prevention of first-ever fractures in the highest-risk settings is on the horizon, where there is also a need to move beyond antiresorptives to the study of anabolic agents.

Intermittent dosing of zoledronic acid based on bone turnover marker assessment reduces vertebral and non-vertebral fractures

Previous studies have demonstrated that the administration of zoledronic acid (ZOL) once yearly for 3 years or once over 3 years, yields similar antifracture efficacy. Bone turnover markers can predict the antifracture efficacy of antiresorptive agents, with procollagen type 1 N-terminal propeptide (P1NP) being the most useful marker. In this retrospective cohort study, we explored the effects of intravenous dosing of ZOL guided by serum (S)-P1NP assessment on bone mineral density (BMD) and fractures. Consenting patients (N = 202, mean age 68.2 years) with osteoporosis were treated with ZOL for an average of 4.4 (range 2-8) years. S-P1NP and BMD were measured at baseline and every 1-2 years. We assessed the number of subsequent vertebral and nonvertebral fractures in the 2-year time periods. The number of patients assessed was 202, 147, 69, and 29 at years 1-2, 3-4, 5-6, and 7-8, respectively. A new ZOL infusion was given if S-P1NP exhibited values above 35 μg/L. BMD increased by 6.2% (SD 4.0) over the first 2 years and stabilized in years 2-8 (P <.05). Median S-P1NP exhibited an initial reduction from 58.0 to 31.3 μg/L at year 2 and then increased to 39.0 μg/L at years 7-8. Compared with fractures observed in the last 2 years before baseline, fracture rates exhibited consistent reductions, for vertebral fractures odds ratio (OR) [95% confidence interval] = 0.61 [0.47, 0.80], P <.001 and for nonvertebral fractures OR = 0.23 [0.18, 0.31], P <.001. In conclusion, intermittent dosing of intravenous ZOL based on the assessment of S-P1NP with cut-off at 35 μg/L resulted in an initial increase followed by a stable BMD, suppression of S-P1NP, and stable reduction of fractures for 8 years. Only 39% of patients needed more than one infusion. This approach reduces healthcare costs and might also reduce the risk of rare side effects such as osteonecrosis of the jaw and atypical femoral fracture.

Geographic Variation in Osteoporosis Treatment in Postmenopausal Women: A 15-Year Longitudinal Analysis

Context

Osteoporosis affects more than half of older women, but many are not treated. Whether treatment differs between rural and urban areas is unknown.

Objective

To examine differences in osteoporosis treatment among postmenopausal women living in urban and rural areas of Australia.

Methods

Women participating in the Australian Longitudinal Study on Women's Health, a prospective longitudinal cohort study, born between 1946-1951, and with osteoporosis or fractures, were included. Surveys from 2004 to 2019 were linked to the Pharmaceutical Benefits Scheme (government-subsidized medications) to assess osteoporosis treatment and adherence, comparing geographical areas.

Results

Of the 4259 women included (mean age, 55.6 years), 1703 lived in major cities, 1629 inner regional, 794 outer regional, and 133 remote areas. Over the 15-year follow-up, 1401 (32.9%) women received treatment, including 47.4% of women with osteoporosis and 29.9% with fractures. Women in outer regional and remote areas were less likely to use antiosteoporosis treatment than those in major cities on univariable analysis (outer regional odds ratio, 0.83; 95% CI, 0.72-0.95; remote, 0.65; 0.49-0.86), but this did not remain significant on multivariable analysis. Median duration of use was 10 to 36 months, adherence varied by treatment type (34%-100%) but was not related to incident fractures, and of the women who stopped denosumab, 85% did not receive another consolidating treatment.

Conclusions

One-third of women with osteoporosis/fractures received treatment, and adherence was low. There was no difference in treatment use between urban and rural areas after adjusting for risk factors, although the specific treatment used, and adherence, differed.

Prolonged bone health benefits for breast cancer patients following adjuvant bisphosphonate therapy: the BoHFAB study

Adjuvant bisphosphonates are often recommended in postmenopausal women with early breast cancer at intermediate-to-high risk of disease recurrence, but the magnitude and duration of their effects on bone mineral density (BMD) and bone turnover markers (BTMs) are not well described. We evaluated the impact of adjuvant zoledronate on areal BMD and BTMs in a sub-group of patients who had completed the large 5-yr randomized Adjuvant Zoledronic Acid to Reduce Recurrence (AZURE) trial. About 224 women (recurrence free) who had completed the AZURE trial within the previous 3 mo were recruited from 20 UK AZURE trial sites. One hundred twenty had previously been randomized to zoledronate (19 doses of 4 mg over 5 yr) and 104 to the control arm. BMD and BTMs were assessed at sub-study entry, 6 (BTMs only), 12, 24, and 60 mo following the completion of AZURE. As expected, mean BMD, T-scores, and Z-scores at sub-study entry were higher in the zoledronate vs the control arm. At the lumbar spine, the mean (SD) standardized BMD (sBMD) was 1123 (201) and 985 (182) mg/cm2 in the zoledronate and control arms, respectively (P < .0001). The baseline differences in sBMD persisted at all assessed skeletal sites and throughout the 5-yr follow-up period. In patients completing zoledronate treatment, BTMs were significantly lower than those in the control arm (α- and β-urinary C-telopeptide of type-I collagen, both P < .00001; serum intact pro-collagen I N-propeptide, P < .00001 and serum tartrate-resistant acid phosphatase 5b, P = .0001). Some offset of bone turnover inhibition occurred in the 12 mo following the completion of zoledronate treatment. Thereafter, during the 60 mo of follow-up, all BTMs remained suppressed in the zoledronate arm relative to the control arm. In conclusion, in addition to the known anti-cancer benefits of adjuvant zoledronate, there are likely to be positive, lasting benefits in BMD and bone turnover.

A practical guide to the diagnosis and management of osteoporosis in childhood and adolescence

Osteoporosis in childhood distinguishes itself from adulthood in four important ways: 1) challenges in distinguishing otherwise healthy children who have experienced fractures due to non-accidental injury or misfortunate during sports and play from those with an underlying bone fragility condition; 2) a preponderance of monogenic "early onset" osteoporotic conditions that unveil themselves during the pediatric years; 3) the unique potential, in those with residual growth and transient bone health threats, to reclaim bone density, structure, and strength without bone-targeted therapy; and 4) the need to benchmark bone health metrics to constantly evolving "normal targets", given the changes in bone size, shape, and metabolism that take place from birth through late adolescence. On this background, the pediatric osteoporosis field has evolved considerably over the last few decades, giving rise to a deeper understanding of the discrete genes implicated in childhood-onset osteoporosis, the natural history of bone fragility in the chronic illness setting and associated risk factors, effective diagnostic and monitoring pathways in different disease contexts, the importance of timely identification of candidates for osteoporosis treatment, and the benefits of early (during growth) rather than late (post-epiphyseal fusion) treatment. While there has been considerable progress, a number of unmet needs remain, the most urgent of which is to move beyond the monotherapeutic anti-resorptive landscape to the study and application of anabolic agents that are anticipated to not only improve bone mineral density but also increase long bone cross-sectional diameter (periosteal circumference). The purpose of this review is to provide a practical guide to the diagnosis and management of osteoporosis in children presenting to the clinic with fragility fractures, one that serves as a step-by-step "how to" reference for clinicians in their routine clinical journey. The article also provides a sightline to the future, emphasizing the clinical scenarios with the most urgent need for an expanded toolbox of effective osteoporosis agents in childhood.

Insights into the Mechanism of Osteoporosis and the Available Treatment Options

Osteoporosis, one of the most prevalent bone illnesses, majorly affects postmenopausal women and men over 50 years of age. Osteoporosis is associated with an increased susceptibility to fragility fractures and can result in persistent pain and significant impairment in affected individuals. The primary method for diagnosing osteoporosis involves the assessment of bone mineral density (BMD) through the utilisation of dual energy x-ray absorptiometry (DEXA). The integration of a fracture risk assessment algorithm with bone mineral density (BMD) has led to significant progress in the diagnosis of osteoporosis. Given that osteoporosis is a chronic condition and multiple factors play an important role in maintaining bone mass, comprehending its underlying mechanism is crucial for developing more effective pharmaceutical interventions for the disease. The effective management of osteoporosis involves the utilisation of appropriate pharmacological agents in conjunction with suitable dietary interventions and lifestyle modifications. This review provides a comprehensive understanding of the types of osteoporosis and elucidates the currently available pharmacological treatment options and their related mechanism of action and usage.

Single pharmacy governed denosumab home administration: optimal adherence by means of a fracture liaison service (FLS) and home care collaboration

Low adherence for denosumab (Dmab, Prolia®) is of major concern. Dutch pharmacies deliveries were calculated recently being 76.5% for a total of 3 injections.

INTRODUCTION

Comparing a model where the prescriber maintains responsibility for adherence (model HC1) (Dmab is purchased and dispensed by patient's own community pharmacy and administered through a home care service (HC)) or an all-in-one model where the pharmacist maintains responsibility for the adherence (Dmab is purchased, dispensed, and administered by a pharmacist's HC) (HC2).

METHODS

We counted the number of Dmab injections, follow-up appointments on time, Dmab administrations delayed to a maximum of 60 days, the number of Dmab discontinuations, and all causes legally traceable under EU privacy act (EDPR).

RESULTS

Home care started by 2014 (study closure in 2021) and included 711 Dmab injections to 256 unique patients: HC1: 536 and HC2: 175 orders. The whole group received on average 2.8 Dmab injections by consistent intervals of about 182 days. Average administration after the latest Dmab injection: 272.8 days (HC1: 362.0 and HC2: 124.0 days). Administration of a subsequent injection > 60 days occurred in 26.6% (HC1: 38.8% and HC2: 6.2%; OR = 9.49). After adjustment for no more than three Dmab injections administered per patient, it occurred in 27.3% (HC1: 51.8% and HC2 4.4%; OR = 23.34).

CONCLUSION

It was possible to achieve 94% adherence for Dmab injections treatment just by transferring the complete supply chain to one pharmacy-initiated home care provider after treatment initiation by either a physician or FLS health care professional.

Durability and delayed treatment effects of zoledronic acid on bone loss after spinal cord injury: a randomized, controlled trial

A single infusion of zoledronic acid (ZOL) after acute spinal cord injury (SCI) attenuates bone loss at the hip (proximal femur) and knee (distal femur and proximal tibia) for at least 6 months. The objective of this study was to examine the effects of timing and frequency of ZOL over 2 years. In this double-blind, placebo-controlled trial, we randomized 60 individuals with acute SCI (<120 days of injury) to receive either ZOL 5-mg infusion (n = 30) or placebo (n = 30). After 12 months, groups were again randomized to receive ZOL or placebo, resulting in four treatment groups for year 2: (i) ZOL both years; (ii) ZOL year 1, placebo year 2; (iii) placebo year 1, ZOL year 2; and (iv) placebo both years. Our primary outcome was bone loss at 12 months; compared to placebo, a single infusion of ZOL attenuated bone loss at the proximal femur, where median changes relative to baseline were -1.7% to -2.2% for ZOL versus -11.3% to -12.8% for placebo (p < 0.001). Similarly, the distal femur and proximal tibia showed changes of -4.7% to -9.6% for ZOL versus -8.9% to -23.0% for placebo (p ≤ 0.042). After 24 months, differences were significant at the proximal femur only (-3.2% to -6.0% for ZOL vs. -16.8% to -21.8% for placebo; p ≤ 0.018). Although not statistically significant, median bone density losses suggested some benefit from two annual infusions compared to a single baseline infusion, as well as from a single infusion 12 months after baseline compared to 2 years of placebo; therefore, further investigation in the 12-month to 24-month treatment window is warranted. No unanticipated adverse events associated with drug treatment were observed. In summary, ZOL 5-mg infusion after acute SCI was well-tolerated and may provide an effective therapeutic approach to prevent bone loss in the first few years following SCI. © 2021 American Society for Bone and Mineral Research (ASBMR).

Effectiveness of bisphosphonates on bone mineral density in osteopenic postmenopausal women: A systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Various bisphosphonate agents have been proven to be effective in preventing bone loss and fracture in osteopenic postmenopausal women. This study was designed to compare the effectiveness of various BPs on preventing the loss of bone mineral density (BMD) for postmenopausal women with osteopenia.

METHODS

PubMed, EMBASE, and Cochrane Central Register of Controlled Trials were screened up to identify randomized controlled trails comparing effectiveness of BPs or placebo on the BMD of postmenopausal women with osteopenia. Network meta-analysis and standard pair-wise meta-analyses were performed. The main outcomes include the percentage changes of 6-, 12-, 24-, and 36-month BMD at lumbar, total hip and femoral neck, and frequencies of new fractures and severe adverse events.

RESULTS

Fourteen randomized controlled trials were eligible, involving 11,540 participants. No significant difference was presented among the available interventions for the 6-month BMD at 3 different sites, but the magnitudes of differences among the treatment regimens became gradually increased along with the extending of follow-up periods. Daily aledronate of more than 5 mg provided the maximal percentage increase on BMD of femoral neck and lumbar spine, while zoledronate provided maximal change on BMD of total hip, at different follow-up periods. This network meta-analysis also demonstrated similar frequencies of new clinical fractures and severe adverse events among different interventions.

CONCLUSIONS

A ranking spectrum depicting the effectiveness on BMD percentage change following interventions with different bisphosphonate regimens was provided. Generally, regimens with zoledronate and aledronate were found to be the most effective interventions in the 3 sites at different end points.

Ten Years of Very Infrequent Zoledronate Therapy in Older Women: An Open-Label Extension of a Randomized Trial

CONTEXT

Intravenous zoledronate prevents bone loss and reduces fracture risk in older adults but the optimal dosing strategy required to achieve each outcome is not known.

OBJECTIVE

To assess the effect of very infrequent zoledronate therapy on bone mineral density (BMD) and markers of bone turnover.

DESIGN AND PARTICIPANTS

An average of 5.5 years after randomization to either a single dose of 5 mg of zoledronateor placebo, 33 of the original cohort of 50 older women with osteopenia entered a 5-year open-label extension study.

SETTING

Academic research center.

INTERVENTION

A 5-mg dose of intravenous zoledronate was administered to all participants.

MAIN OUTCOME MEASURES

BMD and bone turnover were measured annually, generating data over almost 11 years in women who received 5 mg of zoledronate at 0 and 5.5 years (ZZ, n = 16), or placebo at baseline and 5 mg of zoledronate at 5.5 years (PZ, n = 17).

RESULTS

After redosing, BMD in ZZ remained stable, while BMD in PZ increased. At 11 years, changes from baseline BMD in ZZ and PZ were 3.8% (95% confidence interval (CI) 1.1,6.5) and 2.9% (0.3,5.5) at the lumbar spine (P = .61), 0.9% (-1.7,3.5) and -2.8% (-5.3,-0.3) at the total hip (P = .006), and 0.4% (-0.8,1.6) and -0.4% (-1.3,0.5) at the total body (P = .14). Bone turnover markers were similar in the PZ and ZZ groups throughout the 5 years after redosing.

CONCLUSIONS

These results suggest that zoledronate 5 mg administered at a 5.5-year interval prevents bone loss over almost 11 years. Clinical trials to investigate whether very infrequent treatment with zoledronate reduces fracture risk are justified.

Effects of Intravenous Zoledronate on Bone Turnover and Bone Density Persist for at Least 11 Years in HIV-Infected Men

Previously we reported the results of a 4-year extension of a 2-year randomized placebo-controlled trial showing that the antiresorptive effects of two annual 4-mg doses of zoledronate in HIV-infected men persisted for at least 5 years after the second dose. We set out to determine whether the effects on BMD and bone turnover persist beyond 10 years. We invited all participants in the original trial known to be alive and living in New Zealand to attend an additional visit approximately 12 years after trial entry and 11 years after their second dose of study medication. The outcome measures were BMD at the lumbar spine, proximal femur, and total body, and markers of bone turnover. Twenty-five of the 43 men originally enrolled in the trial attended the final visit, representing 25 of 31 (81%) participants alive and residing in New Zealand at the time. The average duration of follow-up was 12.4 years. At the final visit, BMD remained higher in the zoledronate group than the placebo group (lumbar spine 3.7%, 95% CI, 0.1 to 7.3; total hip 3.7%, 95% CI, 1.2 to 6.2; femoral neck 5.0%, 95% CI, 2.1 to 7.9; total body 2.4%, 95% CI, 0.7 to 4.0), and the between-group differences in BMD remained stable between 6 and 12 years. Serum CTx remained lower in the zoledronate group than the placebo group between 6 and 12 years and, at the final visit, was 45% lower (95% CI, 25 to 64) than the placebo group. P1NP was 26% (95% CI, 4 to 48) lower in the zoledronate group than the placebo group at the final visit. In summary, two annual 4-mg doses of zoledronate have effects on bone turnover and BMD in men that persist for at least 11 years after the second dose. © 2019 American Society for Bone and Mineral Research.

Screening to Prevent Osteoporotic Fractures: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Osteoporotic fractures cause significant morbidity and mortality.

OBJECTIVE

To update the evidence on screening and treatment to prevent osteoporotic fractures for the US Preventive Services Task Force.

DATA SOURCES

PubMed, the Cochrane Library, EMBASE, and trial registries (November 1, 2009, through October 1, 2016) and surveillance of the literature (through March 23, 2018); bibliographies from articles.

STUDY SELECTION

Adults 40 years and older; screening cohorts without prevalent low-trauma fractures or treatment cohorts with increased fracture risk; studies assessing screening, bone measurement tests or clinical risk assessments, pharmacologic treatment.

DATA EXTRACTION AND SYNTHESIS

Dual, independent review of titles/abstracts and full-text articles; study quality rating; random-effects meta-analysis.

MAIN OUTCOMES AND MEASURES

Incident fractures and related morbidity and mortality, diagnostic and predictive accuracy, harms of screening or treatment.

RESULTS

One hundred sixty-eight fair- or good-quality articles were included. One randomized clinical trial (RCT) (n = 12 483) comparing screening with no screening reported fewer hip fractures (2.6% vs 3.5%; hazard ratio [HR], 0.72 [95% CI, 0.59-0.89]) but no other statistically significant benefits or harms. The accuracy of bone measurement tests to identify osteoporosis varied (area under the curve [AUC], 0.32-0.89). The pooled accuracy of clinical risk assessments for identifying osteoporosis ranged from AUC of 0.65 to 0.76 in women and from 0.76 to 0.80 in men; the accuracy for predicting fractures was similar. For women, bisphosphonates, parathyroid hormone, raloxifene, and denosumab were associated with a lower risk of vertebral fractures (9 trials [n = 23 690]; relative risks [RRs] from 0.32-0.64). Bisphosphonates (8 RCTs [n = 16 438]; pooled RR, 0.84 [95% CI, 0.76-0.92]) and denosumab (1 RCT [n = 7868]; RR, 0.80 [95% CI, 0.67-0.95]) were associated with a lower risk of nonvertebral fractures. Denosumab reduced the risk of hip fracture (1 RCT [n = 7868]; RR, 0.60 [95% CI, 0.37-0.97]), but bisphosphonates did not have a statistically significant association (3 RCTs [n = 8988]; pooled RR, 0.70 [95% CI, 0.44-1.11]). Evidence was limited for men: zoledronic acid reduced the risk of radiographic vertebral fractures (1 RCT [n = 1199]; RR, 0.33 [95% CI, 0.16-0.70]); no studies demonstrated reductions in clinical or hip fractures. Bisphosphonates were not consistently associated with reported harms other than deep vein thrombosis (raloxifene vs placebo; 3 RCTs [n = 5839]; RR, 2.14 [95% CI, 0.99-4.66]).

CONCLUSIONS AND RELEVANCE

In women, screening to prevent osteoporotic fractures may reduce hip fractures, and treatment reduced the risk of vertebral and nonvertebral fractures; there was not consistent evidence of treatment harms. The accuracy of bone measurement tests or clinical risk assessments for identifying osteoporosis or predicting fractures varied from very poor to good.

Lack of Evidence that Soluble Urate Directly Influences Bone Remodelling: A Laboratory and Clinical Study

INTRODUCTION

Numerous observational studies have reported that serum urate concentration positively correlates with bone density and reduced risk of fractures. The aim of this study was to examine whether soluble urate directly influences bone remodelling.

METHODS

In laboratory studies, the in vitro effects of soluble urate were examined in osteoclast, osteoblast and osteocyte assays at a range of urate concentrations consistent with those typically observed in humans (up to 0.70 mmol/L). The clinical relevance of the in vitro assay findings was assessed using serial procollagen-1 N-terminal propeptide (P1NP) and Month 12 bone density data from a randomised controlled trial of allopurinol dose escalation in people with gout.

RESULTS

Addition of urate in the RAW264.7 cell osteoclastogenesis assay led to small increases in osteoclast formation (ANOVA p = 0.018), but no significant difference in bone resorption. No significant effects on osteoclast number or activity were observed in primary cell osteoclastogenesis or resorption assays. Addition of urate did not alter viability or function in MC3T3-E1 pre-osteoblast, primary human osteoblast, or MLO-Y4 osteocyte assays. In the clinical trial analysis, reducing serum urate over a 12 month period by allopurinol dose escalation did not lead to significant changes in P1NP or differences in bone mineral density.

CONCLUSION

Addition of soluble urate at physiological concentrations does not influence bone remodelling in vitro. These data, together with clinical trial data showing no effect of urate-lowering on P1NP or bone density, do not support a direct role for urate in influencing bone remodelling.

Bone Loss After Denosumab: Only Partial Protection with Zoledronate

A case series of six women with postmenopausal osteoporosis who had received continuous denosumab for 7 years and were then given a single infusion of zoledronate (5 mg) is reported. During denosumab treatment, bone mineral density (BMD) in the spine increased 18.5% (P = 0.006), and total hip BMD by 6.9% (P = 0.03). Post-zoledronate BMDs were measured 18-23 months after treatment, and there were significant declines at each site (P _spine = 0.043, P _hip = 0.005). Spine BMD remained significantly above the pre-denosumab baseline (+9.3%, P = 0.003), but hip BMD was not significantly different from baseline (-2.9%). At the time of post-zoledronate BMD measurements, serum PINP levels were between 39 and 60 μg/L (mean 52 μg/L), suggesting that the zoledronate treatment had not adequately inhibited bone turnover. It is concluded that this regimen of zoledronate administration is not adequate to preserve the BMD gains that result from long-term denosumab treatment.

Effect of single-dose dexamethasone on acute phase response following zoledronic acid: a randomized controlled trial

Zoledronic acid provokes an inflammatory reaction, or acute phase response, in some individuals. We examined whether treatment with dexamethasone could prevent this response. A single dose of dexamethasone 4 mg, given at the time of zoledronic acid infusion, did not influence the incidence or severity of the acute phase response.

INTRODUCTION

The potent bisphosphonate zoledronic acid (ZOL) is used to treat osteoporosis, Paget's disease, and hypercalcemia of malignancy. This medication can provoke an inflammatory reaction, known as the acute phase response (APR). We examined whether glucocorticoid treatment at the time of first exposure to ZOL prevents the development of APR.

METHODS

This double-blind, randomized, controlled trial assessed 40 adults receiving ZOL 5 mg intravenously for the first time. Participants received oral dexamethasone 4 mg (n = 20) or placebo (n = 20) at the time of ZOL infusion. Oral temperature was measured at baseline and three times a day for 3 days following infusion. Symptoms of APR were assessed via questionnaire at baseline then daily for 3 days and again at day 15 post-infusion. Use of rescue medications (paracetamol or ibuprofen) in the 3 days following infusion was evaluated. Primary outcome was between-group difference in temperature change from baseline.

RESULTS

There was no significant difference in temperature change (p = 0.95) or symptom score (p = 0.42) in the 3 days following ZOL between dexamethasone and placebo recipients. Eleven (55%) in the dexamethasone group and 10 (50%) placebo recipients experienced a temperature increase of ≥1 °C (p = 0.99). Seven (35%) in the dexamethasone group and 9 (45%) in the placebo group experienced an increase in symptom score of ≥3 points (p = 0.75). Thirteen (65%) dexamethasone recipients and 12 (60%) in the placebo group required rescue medications (p = 0.99). Dexamethasone was well-tolerated.

CONCLUSIONS

A single dose of dexamethasone 4 mg does not influence the incidence or severity of APR following first exposure to ZOL.

TRIAL REGISTRATION

ACTRN12615000794505.

Frequency of discontinuation of injectable osteoporosis therapies in US patients over 2 years

Little is known about treatment patterns with injectable osteoporosis therapies. At 12 months, the probability of discontinuation was 69.1% among patients using ibandronate, followed by teriparatide (67.1%), zoledronic acid (59.2%), and denosumab (48.8%). By 24 months, discontinuation was higher for each treatment. The majority of US patients discontinue injectable osteoporosis treatment by the end of the first year following initiation.

INTRODUCTION

This study was designed to assess the frequency of treatment discontinuation over time among patients who initiate injectable osteoporosis therapies.

METHODS

This retrospective observational study utilized an administrative claims database to measure discontinuation of injectable osteoporosis therapy, reported at 6-month intervals over 2 years. Eligible patients were aged ≥55 years, had newly initiated injectable osteoporosis therapy between January 2008 and June 2012, and were continuously enrolled in the health plan for ≥1 year prior to and ≥1.5 years after the date the first injectable medication was received (the index date). Follow-up time ranged from 18 to 24 months. Injectable osteoporosis treatments included in the analysis were denosumab, ibandronate, teriparatide, and zoledronic acid. Discontinuation was assessed using Kaplan-Meier survival analysis and was defined at each time point as the percentage of patients who did not receive the dose scheduled for that time point. A 90-day grace period was allowed to accommodate flexibility in the scheduling of post-index re-administrations. Sensitivity analyses assessed discontinuation using grace periods of 60 and 30 days.

RESULTS

A total of 4756 patients met the inclusion criteria for the study, with 617 utilizing denosumab, 233 ibandronate, 778 teriparatide, and 3128 zoledronic acid. At 12 months, discontinuation was highest among patients using ibandronate (69.1%), followed by teriparatide (67.1%), zoledronic acid (59.2%), and denosumab (48.8%). By 24 months, discontinuation was higher for each treatment: 87.5% for ibandronate, 87.9% for teriparatide, 79.8% for zoledronic acid, and 64.3% for denosumab.

CONCLUSIONS

The majority of US patients discontinue injectable osteoporosis treatment by the end of the first year following initiation.

Osteonecrosis of the jaw (ONJ) and atypical femoral fracture (AFF) in an osteoporotic patient chronically treated with bisphosphonates

The aim of the study is to report the rare association of two complications of long-term treatment of osteoporosis with bisphosphonates in the same Caucasian elderly patient. A female patient of Italian descent, age 87 years, consulted in February 2013. She had a history of osteoporosis and had taken alendronate weekly for 7 years (1999-2006). Due to low back pain, an orthopedist had indicated i.v. zoledronic acid, 5 mg/year for 3 years (2006-2008). She received occasional supplements of ergocalciferol. In 2009, she suffered a fall and sustained a subtrochanteric fracture of the left femur. She was operated on and recovered uneventfully. In 2012, she consulted a dentist due to loose teeth. She underwent the removal of a molar and was given a denture. She had discomfort when using the prosthesis, and developed an ulceration in the gum of the mandible, which exposed the bone and did not heal for 2 months. After radiologic studies, the diagnosis was osteonecrosis of the jaw. She improved after surgical debridement and local and systemic antibiotics. In early 2013, laboratory tests were normal except for a slight elevation of serum PTH and CTX-I. Calcitriol 0.25 mcg/day was prescribed; after 3 months serum calcium, phosphate, PTH, and CTX-I showed no variation. Two years later, she experienced acute low back pain after a fall; MRI showed recent crushing of D12, and chronic deformities of D11 and L1. Bone densitometry of her right hip (DXA) showed a T-score of -2.3 at the femoral neck. An X-ray film of the right femur showed diffuse thickening of both cortices. She was treated with nasal calcitonin and analgesics. After the back pain subsided, she was treated with s.c. denosumab. Although the association of ONJ and AFF was known in cancer patients treated with high doses of bisphosphonates, it is very rare in patients with osteoporosis receiving these drugs at usual doses. Only three cases have been reported, all in oriental women. This appears to be the first reported case in a Caucasian woman.

Incidence of Atypical Femur Fractures in Cancer Patients: The MD Anderson Cancer Center Experience

Atypical femoral fractures (AFFs) are rare adverse events attributed to bisphosphonate (BP) use. Few cases of AFF in cancer have been described; the aim of this study is to identify the incidence and risk factors for AFF in a large cancer center. This retrospective study was conducted at the MD Anderson Cancer Center. The incidence rate of AFF among BP users was calculated from January 1, 2004 through December 31, 2013. The control group (n = 51) included 2 or 3 patients on BPs matched for age (≤1 year) and gender. Logistic regression analysis was used to assess the relationship between clinical characteristics and AFF. Twenty-three AFF cases were identified radiographically among 10,587 BP users, the total BP exposure was 53,789 months (4482 years), and the incidence of AFF in BP users was 0.05 cases per 100,000 person-years. Meanwhile, among 300,553 patients who did not receive BPs there were 2 cases of AFF as compared with the 23 cases noted above. The odds ratio (OR) of having AFF in BP users was 355.58 times higher (95% CI, 84.1 to 1501.4, p < 0.0001) than the risk in non-BP users. The OR of having AFF in alendronate users was 5.54 times greater (OR 5.54 [95% CI, 1.60 to 19.112, p = 0.007]) than the odds of having AFF among other BP users. Patients who were on zoledronic acid (ZOL) had smaller odds of developing AFF compared with other BP users in this matched case control sample. AFFs are rare, serious adverse events that occur in patients with cancer who receive BP therapy. Patients with cancer who receive BPs for prior osteoporosis therapy or for metastatic cancer are at higher risk of AFF. © 2016 American Society for Bone and Mineral Research.

The management of osteoporosis in children

This article reviews the manifestations and risk factors associated with osteoporosis in childhood, the definition of osteoporosis and recommendations for monitoring and prevention. As well, this article discusses when a child should be considered a candidate for osteoporosis therapy, which agents should be prescribed, duration of therapy and side effects. There has been significant progress in our understanding of risk factors and the natural history of osteoporosis in children over the past number of years. This knowledge has fostered the development of logical approaches to the diagnosis, monitoring, and optimal timing of osteoporosis intervention in this setting. Current management strategies are predicated upon monitoring at-risk children to identify and then treat earlier rather than later signs of osteoporosis in those with limited potential for spontaneous recovery. On the other hand, trials addressing the prevention of the first-ever fracture are still needed for children who have both a high likelihood of developing fractures and less potential for recovery. This review focuses on the evidence that shapes the current approach to diagnosis, monitoring, and treatment of osteoporosis in childhood, with emphasis on the key pediatric-specific biological principles that are pivotal to the overall approach and on the main questions with which clinicians struggle on a daily basis. The scope of this article is to review the manifestations of and risk factors for primary and secondary osteoporosis in children, to discuss the definition of pediatric osteoporosis, and to summarize recommendations for monitoring and prevention of bone fragility. As well, this article reviews when a child is a candidate for osteoporosis therapy, which agents and doses should be prescribed, the duration of therapy, how the response to therapy is adjudicated, and the short- and long-term side effects. With this information, the bone health clinician will be poised to diagnose osteoporosis in children and to identify when children need osteoporosis therapy and the clinical outcomes that gauge efficacy and safety of treatment.

Reference intervals for bone turnover markers in Spanish premenopausal women

The aims of this study were to establish robust reference intervals and to investigate the factors influencing bone turnover markers (BTMs) in healthy premenopausal Spanish women.

A total of 184 women (35–45 years) from 13 centers in Catalonia were analyzed. Blood and second void urine samples were collected between 8 a.m. and 10 a.m. after an overnight fast. Serum procollagen type I amino-terminal propeptide (PINP) and serum cross-linked C-terminal telopeptide of type I collagen (CTX-I) were measured by two automated assays (Roche and IDS), bone alkaline phosphatase (bone ALP) by ELISA, osteocalcin (OC) by IRMA and urinary NTX-I by ELISA. PTH and 25-hydroxyvitamin D (25OHD) levels were measured. All participants completed a questionnaire on lifestyle factors.

Reference intervals were: PINP: 22.7–63.1 and 21.8–65.5 μg/L, bone ALP: 6.0–13.6 μg/L, OC: 8.0–23.0 μg/L, CTX-I: 137–484 and 109–544 ng/L and NTX-I: 19.6–68.9 nM/mM. Oral contraceptive pills (OCPs) influenced PINP (p=0.007), and low body mass index (BMI) was associated with higher BTMs except for bone ALP. Women under 40 had higher median values of most BTMs. CTX-I was influenced by calcium intake (p=0.010) and PTH (p=0.007). 25OHD levels did not influence BTMs. Concordance between the two automated assays for PINP and particularly CTX-I was poor.

Robust reference intervals for BTMs in a Southern European country are provided. The effects of OCPs and BMI on their levels are significant, whilst serum 25OHD levels did not influence BTMs. Age, calcium intake, BMI and PTH influenced CTX-I. The two automated assays for measuring PINP and CTX-I are not interchangeable.

Should we prescribe calcium or vitamin D supplements to treat or prevent osteoporosis?

Systematic reviews of randomized, controlled trials (RCTs) are considered the highest level of evidence to inform clinical practice. Meta-analyses of large RCTs of calcium and/or vitamin D supplements completed in the last 15 years provide strong evidence for clinical recommendations. These meta-analyses with data for > 50,000 older adults reported that calcium with or without vitamin D has only weak, inconsistent effects on fracture, and that vitamin D without calcium has no effect on fracture. Only one RCT of co-administered calcium and vitamin D in frail, institutionalized, elderly women with low dietary calcium intake and vitamin D levels showed significant reductions in fracture risk. These RCTs have also reported previously unrecognized adverse events of calcium supplements including kidney stones, myocardial infarction, hypercalcemia, and hospitalization with acute gastrointestinal symptoms. The small risk of these important adverse effects, together with the moderate risk of minor side-effects such as constipation, probably outweighs any benefits of calcium supplements on fracture. These data suggest the role for calcium and vitamin D supplements in osteoporosis management is very limited. Neither calcium nor vitamin D supplements should be recommended for fracture prevention in community-dwelling adults, although vitamin D should be considered for prevention of osteomalacia in at-risk individuals.

Diagnosis and treatment of pediatric osteoporosis

PURPOSE OF REVIEW

Progress toward identifying and treating disorders of bone fragility in pediatric patients has been considerable in recent years. This article will summarize several key advances in the management of osteoporosis in children and adolescents.

RECENT FINDINGS

Recommendations from the 2013 pediatric Position Development Conference provide expert guidance for evaluating bone health in younger patients. The diagnosis of pediatric osteoporosis can be made in a child with low-trauma vertebral fractures or a combination of low bone mass and long bone fractures. Management of bone fragility includes optimizing nutrition, activity, and treatment of the underlying disease. Pharmacologic agents can be considered if these measures fail to prevent further bone loss or fractures. Although the efficacy and safety of several intravenous and oral bisphosphonates have been examined, there is still no consensus on the optimal drug, dose, or duration of treatment. Observational studies of children with secondary osteoporosis provide insight into risk factors for fracture or the potential for recovery.

SUMMARY

Despite advances in the diagnosis and treatment of pediatric osteoporosis, more research is needed. Randomized controlled trials of pharmacologic agents should be defined to target those identified at the highest risk by observational studies.

VIDEO ABSTRACT

http://links.lww.com/COE/A9

Atypical femur fractures: a review

Bisphosphonates are one of the most commonly prescribed medications for the treatment of osteoporosis. Their use has greatly decreased the number of osteoporosis-related vertebral and nonvertebral fractures. Recently, however, a relationship between long-term bisphosphonate use and subtrochanteric and femoral shaft fractures has been elucidated. These low-energy fractures, termed atypical femur fractures, exhibit unique characteristics in their pathophysiology, presentation, and radiographic appearance compared with more traditional high-energy femur fractures. Here we provide a review based on the most recent literature of the pathophysiology, presentation, evaluation, and management of these fractures. Despite an abundance of literature, atypical femur fractures remain difficult to treat, and surgeons must be aware of the tricks and complications associated with their management.

Intravenous zoledronic Acid given every 6 months in childhood osteoporosis

AIM

To evaluate the safety and efficacy of 12 months of zoledronic acid (ZA) administered every 6 months to children with osteoporosis.

METHODS

Retrospective cohort study of 27 patients (16 male, 11 female) treated with ZA (0.05 mg/kg/dose) every 6 months for 1 year. 20 were immobile, 4 steroid-induced osteoporosis, 2 idiopathic osteoporosis and 1 neurofibromatosis type 1. 16 had long bone fractures and 12 had vertebral wedging at baseline. Mineral homeostasis, bone mineral density (BMD) and vertebral morphometry were evaluated at baseline and 12 months. Results were compared to published data on 3-monthly ZA treatment.

RESULTS

Median age at ZA start was 10.5 years (range 6.2-13.3). Following the first infusion, 2 developed asymptomatic hypocalcemic, 14 developed temperature > 38°C, 13 aches/pain and 6 nausea. At 12 months, there was reduction in bone turnover and improvement in BMD and vertebral shape. No patient fractured after starting ZA. Growth was normal. Outcomes were similar to 3-monthly ZA.

CONCLUSION

ZA administered 6-monthly was associated with acute phase reaction to the first dose and improvement in BMD, reduction in bone turnover and improved vertebral shape at 12 months.

Osteonecrosis of the jaws in patients assuming oral bisphosphonates for osteoporosis: a retrospective multi-hospital-based study of 87 Italian cases

BACKGROUND

Bisphosphonates (BPs) are currently the chief drugs for the prevention/treatment of osteoporosis; one of their adverse effects is the osteonecrosis of the jaw (BRONJ). The primary endpoints of this multi-center cross-sectional study are: i) an observation of the clinical features of BRONJ in 87 osteoporotic, non-cancer patients; and ii) an evaluation of their demographic variables and comorbidities.

METHODS

87 BRONJ patients in therapy for osteoporosis with BPs from 8 participating clinical Italian centers were consecutively identified and studied. After BRONJ diagnosis and staging, comorbidities and data relating to local and drug-related risk factors for BRONJ were collected.

RESULTS

77/87 (88.5%) patients in our sample used alendronate as a BP type; the duration of bisphosphonate therapy ranged from 2 to 200 months, and 51.7% of patients were in treatment for ≤ 38 months (median value). No comorbidities or local risk factors were observed in 17 (19.5%) patients, indicating the absence of cases belonging to BRONJ forms triggered by surgery. BRONJ localization was significantly associated with age: an increased risk of mandible localization (p=0.002; OR=6.36, 95%CI=[1.89; 21.54]) was observed for those over 72 yrs. At multivariate analysis, the increased risk of BRONJ in the mandible for people over 72 yrs (OR'=6.87, 95%CI=[2.13; 2.21]) was confirmed for a BP administration >56 months (OR'=4.82, 95%CI=[2.13; 22.21]).

CONCLUSION

Our study confirms the fundamental necessity of applying protocols of prevention in order to reduce the incidence of BRONJ in osteoporotic, non-cancer patients in the presence of comorbidities and/or local risk factor as well as, less frequently, in their absence.

Atypical femoral fractures: a review of the literature

Bisphosphonates are the most commonly used drugs worldwide for treating osteoporosis. Atypical femoral fractures most commonly are associated with prolonged bisphosphonate use. They also may occur with denosumab use or in patients without a history of using these drugs. In this article, we provide a comprehensive review of the mechanism of action of bisphosphonate and the definition, incidence, epidemiology, pathogenesis, diagnosis, management, and prevention of atypical femoral fractures.

No reduction in circulating preosteoclasts 18 months after treatment with zoledronate: analysis from a randomized placebo controlled trial

The conventional model that bisphosphonates bind to the bone surface and inhibit mature osteoclasts does not convincingly explain the prolonged duration of action of zoledronate. We hypothesized that zoledronate on the bone surface adjacent to marrow cells impairs osteoclastogenesis, contributing to sustained inhibition of resorption. In this case, numbers of circulating preosteoclasts may be reduced after zoledronate treatment. This study assessed this possibility in subjects from a clinical trial. Twenty-two osteopenic women participating in a randomized, controlled trial comparing zoledronate 5 mg with placebo were recruited, 18 months after administration of study drug. Peripheral blood mononuclear cells were analyzed for the presence of osteoclast precursors using flow cytometry for preosteoclast markers and the ability to form osteoclast-like cells in culture with RANKL and M-CSF. There was no difference in the percentage of CD14(+)/CD11b(+) cells in peripheral blood between the two groups. The numbers of TRAP(+) multinucleated cells in cultures in the absence of RANKL and M-CSF were very low in both groups, but a significantly higher number of these cells was observed in the zoledronate group compared with the placebo group (p = 0.01). The number of TRAP(+) multinucleated cells and resorption pits following culture with RANKL and M-CSF did not differ between the two groups. Serum P1NP was reduced 53 % at 18 months in the zoledronate group but unchanged in the placebo group. These results do not support the hypothesis that the inhibitory action of zoledronate contributes to its prolonged action on preosteoclasts within bone marrow.

The impact of dietary calcium intake and vitamin D status on the effects of zoledronate

We investigated whether baseline dietary calcium intake or vitamin D status modified the effects of zoledronate. Neither variable influenced the effect of zoledronate on bone mineral density, bone turnover, or risk of acute phase reaction, suggesting that co-administration of calcium and vitamin D supplements with zoledronate may not always be necessary.

INTRODUCTION

Calcium and vitamin D supplements are often co-administered with bisphosphonates, but it is unclear whether they are necessary for therapeutic efficacy or minimizing side effects of bisphosphonates. We investigated whether baseline dietary calcium intake or vitamin D status modified the effect of zoledronate on bone mineral density (BMD) or bone turnover at 1 year, or the risk of acute phase reactions (APR).

METHODS

Data were pooled from two trials of zoledronate in postmenopausal women without vitamin D deficiency in which calcium and vitamin D were not routinely administered. The cohort (zoledronate n = 154, placebo n = 68) was divided into subgroups by baseline dietary calcium intake (<800 vs. ≥800 mg/day) and vitamin D status [25-hydroxyvitamin D (25OHD) <50 vs. ≥50 nmol/L, and <75 nmol/L vs. ≥75 nmol/L] and treatment × subgroup interactions tested.

RESULTS

There were 52, 86, and 36 % of the zoledronate group and 64, 94, and 46 % of the placebo group that had dietary calcium intake ≥800 mg/day, 25OHD ≥50 nmol/L, and 25OHD ≥75 nmol/L, respectively. There were no significant interactions between treatment and either baseline dietary calcium or baseline vitamin D status for lumbar spine BMD, total hip BMD, the bone turnover markers P1NP and β-CTx, or the risk of an APR. There was also no three-way interaction between baseline dietary calcium intake, baseline vitamin D status, and treatment for any of these variables.

CONCLUSIONS

Baseline dietary calcium intake and vitamin D status did not alter the effects of zoledronate, suggesting that co-administration of calcium and vitamin D with zoledronate may not be necessary for individuals not at risk of marked vitamin D deficiency.

Zoledronic acid versus alendronate for the prevention of bone loss after heart or liver transplantation

CONTEXT

The first year after transplantation is characterized by rapid bone loss.

OBJECTIVE

The aim of this study was to compare zoledronic acid (zoledronate) and alendronate for prevention of transplantation bone loss.

DESIGN AND SETTING

A randomized clinical trial was conducted at a transplantation center.

PATIENTS

The study included 84 adults undergoing heart or liver transplantation and a concurrently transplanted, nonrandomized reference group of 27 adults with T scores greater than -1.5.

INTERVENTIONS

Alendronate (70 mg weekly for 12 months) or one 5-mg infusion of zoledronate were both initiated 26 ± 8 d after transplantation.

MAIN OUTCOME MEASURES

The primary outcome was total hip bone mineral density (BMD) 1 yr after transplantation. Secondary outcomes included femoral neck and lumbar spine BMD and serum C-telopeptide, a bone resorption marker.

RESULTS

In the reference group, BMD declined at the spine and hip (P < 0.001). In the randomized groups, hip BMD remained stable. Spine BMD increased in the zoledronate group and did not change in the alendronate group; at 12 months, the 2.2% difference between groups (95% confidence interval, 0.6 to 3.9%; P = 0.009) favored zoledronate. In heart transplant patients, spine BMD declined in the alendronate and increased in the zoledronate group (-3.0 vs. +1.6%, respectively; between-group difference, 4.2%; 95% confidence interval, 2.1 to 6.3%; P < 0.001). In liver transplant patients, spine BMD increased comparably in both groups. Twelve-month C-telopeptide was lower in the zoledronate group than in the alendronate group (79 vs. 49%; P = 0.04).

CONCLUSIONS

One 5-mg infusion of zoledronate and weekly alendronate prevent bone loss at the hip and, in liver transplant patients, increase spine BMD. In heart transplant patients, spine bone BMD remained stable with zoledronate but decreased with alendronate.

Bone turnover markers: use in osteoporosis

Biochemical markers of bone turnover (bone turnover markers, BTMs) can be used to study changes in bone remodelling in osteoporosis. Investigators and clinicians should be aware of the appropriate sample collection and storage conditions for optimum measurements of these markers. Improvements in the variability of BTM measurements have resulted from the development of assays for automated analysers, and from international consensus regarding their use. Appropriate reference intervals should be used for the optimum interpretation of results. BTMs can provide information that is useful for the management of patients with osteoporosis, for both the initial clinical assessment and for guiding and monitoring of treatment. BTMs are clinically useful to determine possible causes of secondary osteoporosis by identifying patients with high bone turnover and rapid bone loss. In the follow-up of treatment response, BTM levels respond rapidly to both anabolic and antiresorptive treatments. BTM changes can also be used for understanding the mechanism of action of drugs in development and identifying the correct dose; they are also potentially useful as surrogate biomarkers for fracture.

Five years of anti-resorptive activity after a single dose of zoledronate--results from a randomized double-blind placebo-controlled trial

Intravenous zoledronate 5 mg, administered annually, prevents fractures in people with osteoporosis, but the optimal dosing schedule is not known. Previously, we reported that a single dose of 5 mg zoledronate stably decreased bone turnover and increased bone mineral density (BMD) for 3 years in a randomized controlled trial in 50 postmenopausal women with osteopenia. We have now completed a 2-year double-blind extension of this trial, during which no additional treatment was administered. The primary endpoint was change in the bone turnover markers procollagen type-I N-terminal propeptide (P1NP) and β-C-terminal telopeptide of type I collagen (β-CTX); the secondary endpoint was change in BMD at lumbar spine, total hip and total body. Mean levels of the each of the bone turnover markers were lower in the zoledronate group throughout the study (P<0.0001 for each marker). After 5 years, mean (95% CI) levels of β-CTX and P1NP were 277 ng/L (150, 404) and 28 μg/L (16, 40) lower in the zoledronate group, corresponding to reductions of 48% and 45%, respectively. BMD was higher in the zoledronate group during the study (P<0.0001 for each site). After 5 years, BMD in the zoledronate group was higher by 4.2% (1.1, 7.2) at the lumbar spine, by 5.3% (2.7, 7.9) at the total hip, and by 2.7% (1.1, 4.2) at the total body. These findings suggest that the anti-resorptive effects of a single 5 mg dose of zoledronate persist for at least 5 years in postmenopausal women. Trials assessing the anti-fracture efficacy of dosing intervals of zoledronate of up to 5 years are justified.

Effects of intravenous zoledronate on bone turnover and bone density persist for at least five years in HIV-infected men

CONTEXT

In HIV-infected men, the antiresorptive effects of zoledronate persist for at least 2 yr after the second annual dose.

OBJECTIVE

Our objective was to determine the duration of action of zoledronate in men.

DESIGN AND SETTING

This was 4-yr extension of a 2-yr, double-blind, randomized, placebo-controlled trial at an academic research center.

PARTICIPANTS

Participants included 43 HIV-infected men with bone mineral density (BMD) T score below -0.5, 35 of whom entered the extension study.

INTERVENTION

Intervention was annual administration of 4 mg iv zoledronate or placebo at baseline and 1 yr and no intervention subsequently.

MAIN OUTCOME MEASURES

We evaluated changes in the bone turnover markers, serum osteocalcin and serum C-telopeptide (CTx), and changes in BMD at the lumbar spine, total hip, and total body.

RESULTS

There was no time × treatment interaction between 1 and 5 yr after the second zoledronate dose for osteocalcin or CTx (P > 0.4) or any BMD site (P > 0.7). Between 1 and 5 yr after the second dose, on average, osteocalcin was 41% lower (95% confidence interval = 19-62%; P < 0.001), CTx 52% lower (33-71%; P < 0.001), lumbar spine BMD 3.7% greater (0.3-7.0%; P = 0.03), total hip BMD 2.3% greater (0.3-4.3%; P = 0.02), and total body BMD 2.5% greater (0.8-4.1%; P = 0.004) in the zoledronate group than the placebo group. Five years after the second dose, the between-groups differences were 38% (13-62%) for osteocalcin, 49% (20-77%) for CTx, 3.5% (0.7-6.7%) for lumbar spine BMD, 3.4% (1.4-5.4%) for total hip BMD, and 1.6% (0.2-3.1%) for total body BMD.

CONCLUSION

The effects of two annual 4-mg doses of zoledronate in men persist for at least 5 yr after the second dose. Larger trials assessing the antifracture efficacy of less frequent dosing of zoledronate are justified.

Postmenopausal osteoporosis treatment with antiresorptives: effects of discontinuation or long-term continuation on bone turnover and fracture risk--a perspective

Osteoporosis may be a lifelong condition. Robust data regarding the efficacy and safety of both long-term osteoporosis therapy and therapy discontinuation are therefore important. A paucity of clinical trial data regarding the long-term antifracture efficacy of osteoporosis therapies necessitates the use of surrogate endpoints in discussions surrounding long-term use and/or discontinuation. Long-term treatment (beyond 3-4 years) may produce further increases in bone mineral density (BMD) or BMD stability, depending on the specific treatment and the skeletal site. Bisphosphonates, when discontinued, are associated with a prolonged reduction in bone turnover markers (BTMs), with a very gradual increase to pretreatment levels within 3 to 60 months of treatment cessation, depending on the bisphosphonate used and the prior duration of therapy. In contrast, with nonbisphosphonate antiresorptive agents, such as estrogen and denosumab, BTMs rebound to above pretreatment values within months of discontinuation. The pattern of BTM change is generally mirrored by a more or less rapid decrease in BMD. Although the prolonged effect of some bisphosphonates on BTMs and BMD may contribute to residual benefit on bone strength, it may also raise safety concerns. Adequately powered postdiscontinuation fracture studies and conclusive evidence on maintenance or loss of fracture benefit is lacking for bisphosphonates. Similarly, the effects of rapid reversal of bone turnover upon discontinuation of denosumab on fracture risk remain unknown. Ideally, studies evaluating the effects of long-term treatment and treatment discontinuation should be designed to provide head-to-head "offset" data between bisphosphonates and nonbisphosphonate antiresorptive agents. In the absence of this, a clinical recommendation for physicians may be to periodically assess the benefits/risks of continuation versus discontinuation versus alternative management strategies.

A retrospective analysis of extended-interval dosing and the impact on bisphosphonate compliance in the US Military Health System

This study evaluated whether patients treated with bisphosphonates in the US Military Health System were more compliant with treatment given monthly versus weekly. While medication compliance did improve with treatment given monthly, overall compliance with bisphosphonates was still suboptimal suggesting the need for further strategies to improve compliance with treatment for osteoporosis.

INTRODUCTION

The study objective was to evaluate the relationship between bisphosphonate dosing interval and medication compliance among new users initiating oral bisphosphonates.

METHODS

We conducted a retrospective observational cohort study of administrative claims data in the US Military Health System to examine medication compliance among 22,363 new users of oral bisphosphonates starting weekly (68%) or monthly (32%) therapy. Medication compliance during the first year of treatment was measured using two methods: (1) medication possession ratio (MPR) with compliance defined as ≥80% of days covered and (2) time to first gap of more than 30 days following initiation. Logistic regression and a proportional hazards model were used to detect differences in medication compliance between cohorts.

RESULTS

After the first year of therapy, 57% of subjects were not compliant with bisphosphonates (MPR <80%), while 84% experienced a gap in treatment of more than 30 days. After adjustment for study covariates, the odds of a patient being compliant with treatment was 21% higher among monthly users compared to weekly users (OR 1.207, 95% confidence interval (CI) 1.119-1.257). Similarly, the risk of experiencing a 30-day gap in treatment was 6% lower among monthly users compared to weekly users (HR 0.934, 95% CI 0.905-0.964).

CONCLUSIONS

Patients receiving oral bisphosphonates on a monthly basis showed higher rates of medication compliance compared to weekly dosing in our study. However, compliance with bisphosphonates among all new users was suboptimal, suggesting the need for improved strategies to enhance compliance with oral bisphosphonates in the US Military Health System.

Denosumab for the prevention of skeletal-related events in patients with bone metastasis from solid tumor

Most patients with advanced malignancy develop bone metastases during the course of their disease. For the remainder of the patient's life, these bone metastases lead to skeletal-related events such as pathologic fractures and spinal cord compression, as well as bone pain or lesions requiring palliative radiation therapy or surgery to prevent or treat fractures. Skeletal-related events result in increased morbidity, mortality and health care costs. For the past decade, intravenous bisphosphonates (zoledronic acid, pamidronate) have been recognized as the primary pharmacologic options in the prevention or treatment of skeletal-related events in patients with bone metastasis. Recently, the United States Food and Drug Administration approved denosumab, a fully human monoclonal antibody, for the prevention of skeletal-related events in patients with bone metastases from solid tumors. Three prominent clinical trials were conducted to establish the efficacy of denosumab. In two of three trials, denosumab was found to delay the time to first skeletal-related event significantly more than zoledronic acid in patients with breast or castration-resistant prostate cancer with bone metastasis. The third trial found denosumab to be noninferior to zoledronic acid in patients with metastases from solid tumors, excluding breast and prostate solid tumors. Overall survival and progression-free survival were similar between zoledronic acid and denosumab. Thus, evidence is insufficient to prove a greater efficacy of one agent over the other. According to the American Society of Clinical Oncology and the National Comprehensive Cancer Network, patients with bone metastasis should have zoledronic acid, pamidronate, or denosumab (with calcium and vitamin D supplementation) added to their chemotherapy regimen if they have an expected survival of 3 months or longer and have adequate renal function.

Low-dose zoledronate in osteopenic postmenopausal women: a randomized controlled trial

CONTEXT

Annual iv administration of 5 mg zoledronate decreases fracture risk. The skeletal effects of annual treatment with doses of zoledronate under 4 mg have not been assessed.

OBJECTIVE

Our objective was to determine the skeletal effects of single doses of zoledronate of 5 mg or less.

DESIGN, SETTING, AND PARTICIPANTS

This was a double-blind, randomized, placebo-controlled trial over 1 yr at an academic research center in 180 postmenopausal women with osteopenia.

INTERVENTION

Intervention was a single baseline administration of iv zoledronate in doses of 1, 2.5, or 5 mg, or placebo.

MAIN OUTCOME MEASURES

The primary endpoint was change in bone mineral density (BMD) at the lumbar spine. Secondary endpoints were change in BMD at the proximal femur and total body and changes in biochemical markers of bone turnover.

RESULTS

After 12 months, change in spine BMD was greater in each of the zoledronate groups than in the placebo group [mean (95% confidence interval) difference vs. placebo was 3.5% (2.2-4.8%) for 1 mg, 4.0% (2.7-5.3%) for 2.5 mg, and 3.6% (2.3-4.9%) for 5 mg zoledronate, P < 0.001 for each dose]. Change in BMD at the total hip was greater in each of the zoledronate groups than the placebo group [mean (95% confidence interval) difference vs. placebo was 2.7% (1.9-3.5%) for 1 mg, 3.6% (2.8-4.4%) for 2.5 mg, and 3.6% (2.8-4.4%) for 5 mg zoledronate, P < 0.001 for each dose]. Each of the bone turnover markers, β-C-terminal telopeptide of type I collagen and procollagen type I N-terminal propeptide, was lower by at least 40% in each of the zoledronate groups than the placebo group throughout the trial (P < 0.001 vs. placebo for each marker for each dose). There was evidence for a dose-dependent effect of zoledronate on each of the markers (P for trend <0.001).

CONCLUSION

Annual administration of doses of iv zoledronate lower than 5 mg produces substantial antiresorptive effects. Trials assessing the antifracture efficacy of low doses of zoledronate are justified.

Effect of stopping risedronate after long-term treatment on bone turnover

CONTEXT

Determining how quickly bisphosphonate treatment effects begin to regress is crucial when considering termination of treatment.

OBJECTIVE

Our objective was to assess the effects of 1 yr discontinuation of risedronate use in postmenopausal women with osteoporosis who had previously received risedronate for 2 or 7 yr.

DESIGN AND SETTING

Before initiation of the current study, placebo/5-mg-risedronate patients had received placebo for 5 yr and risedronate for 2 yr, whereas 5-mg-risedronate patients had received risedronate for a total of 7 yr. Risedronate was then discontinued for 1 yr (yr 8).

PATIENTS

Postmenopausal women with osteoporosis who had previously completed the 3-yr Vertebral Efficacy with Risedronate Therapy MultiNational (VERT-MN) pivotal trial, plus a 2-yr extension comparing risedronate or placebo for a total of 5 yr, followed by 2 yr of open-label risedronate treatment were enrolled in these trial extensions.

MAIN OUTCOME MEASURES

Evaluations included changes in type I collagen cross-linked N-telopeptide (NTX)/creatinine (Cr) and bone mineral density (BMD) values, fracture incidence, and adverse events.

RESULTS

After 1 yr of risedronate discontinuation, NTX/Cr levels increased toward baseline in both patient groups vs. the values at the end of yr 7. In both treatment groups, off-treatment total hip and femoral trochanter BMD values decreased, whereas lumbar spine and femoral neck BMD were maintained or slightly increased. The adverse event profiles were similar between the two treatment groups during yr 8.

CONCLUSIONS

One year of discontinuation of risedronate treatment in patients who had received 2 or 7 yr of risedronate therapy led to increases in NTX/Cr levels toward baseline and decreases in femoral trochanter and total hip BMD.

Duration of treatment in postmenopausal osteoporosis: how long to treat and what are the consequences of cessation of treatment?

Although a variety of medications are effective for the treatment of postmenopausal osteoporosis, there is concern that long-term use may incur side effects. Consequently, some have proposed discontinuing or temporarily suspending treatment after a defined period of time. As the benefits of fracture risk reduction may recede during this "drug holiday", the clinician may be faced with deciding when to resume therapy (and with which agent) while avoiding the possible cumulative risk of side effects. This article summarizes data regarding length of treatment and the effects of cessation of treatment on bone density, bone turnover markers, and fracture risk.

Prolonged bisphosphonate release after treatment in women with osteoporosis. Relationship with bone turnover

Bisphosphonates (BP), especially alendronate and risedronate, are the drugs most commonly used for osteoporosis treatment, being incorporated into the skeleton where they inhibit bone resorption and are thereafter slowly released during bone turnover. However, there are few data on the release of BP in patients who have received treatment with these drugs for osteoporosis. This information is essential for evaluating the possibility of BP cyclic therapy in these patients and for controlling their long-term presence in bone tissue. This study evaluated the urinary excretion of alendronate and risedronate in patients treated with these drugs for osteoporosis and analysed its relationship with bone turnover, time of previous drug exposure and time of treatment discontinuation. We included 43 women (aged 65±9.4 years) previously treated with alendronate (36) or risedronate (7) during a mean of 51±3 and 53±3 months, respectively, who had not been treated with other antiosteoporotic treatment and with a median time of discontinuation of 13.5 and 14 months, respectively. Both BP were detected in 24-hour urine by HPLC. In addition, bone formation (PINP) and resorption (NTx) markers were analysed. Both BP were also determined in a control group of women during treatment. Alendronate was detected in 41% of women previously treated with this drug whereas no patient previously treated with risedronate showed detectable urinary values. All control patients showed detectable values of both BP. In patients with detectable alendronate levels, the time of drug cessation was shorter than in patients with undetectable values (12 [6-19] versus 31 [7-72] months, p<0.001). Alendronate was not detected in any patient 19 months after treatment cessation. Alendronate levels were inversely related to time of treatment discontinuation (r=-0.403, p=0.01) and the latter was directly related to NTx (r=0.394, p=0.02). No relationship was observed with age, length of drug exposure, renal function or weight. In conclusion, contrary to risedronate, which was not detected in patients after cessation of treatment, alendronate was frequently detected in women previously treated with this agent up to 19 months after discontinuation of therapy. The relationship between alendronate levels and both bone resorption and time of treatment cessation further indicates a residual effect of this drug in bone, despite treatment discontinuation.

Bisphosphonates in the treatment of osteoporosis: a review of their contribution and controversies

The bisphosphonates have revolutionized the therapy of osteoporosis, particularly the prevention of vertebral and hip fractures. The development of tools for defining absolute fracture risk facilitates their targeting to appropriate, at-risk individuals. Prescribers need to be aware of their common side effects (gastrointestinal intolerance with oral dosing and flu-like illness following intravenous use). Whether these agents carry a real risk of other problems such as osteonecrosis of the jaw and subtrochanteric fractures remains uncertain at the present time. If the association of these problems with bisphosphonates is real, it is important that the major therapeutic benefits that can accrue from bisphosphonates' appropriate targeted use are not lost as a result of the anxiety concerning these extremely rare adverse events.

Bisphosphonates: the first 40 years

The first full publications on the biological effects of the diphosphonates, later renamed bisphosphonates, appeared in 1969, so it is timely after 40years to review the history of their development and their impact on clinical medicine. This special issue of BONE contains a series of review articles covering the basic science and clinical aspects of these drugs, written by some of many scientists who have participated in the advances made in this field. The discovery and development of the bisphosphonates (BPs) as a major class of drugs for the treatment of bone diseases has been a fascinating story, and is a paradigm of a successful journey from 'bench to bedside'. Bisphosphonates are chemically stable analogues of inorganic pyrophosphate (PPi), and it was studies on the role of PPi as the body's natural 'water softener' in the control of soft tissue and skeletal mineralisation that led to the need to find inhibitors of calcification that would resist hydrolysis by alkaline phosphatase. The observation that PPi and BPs could not only retard the growth but also the dissolution of hydroxyapatite crystals prompted studies on their ability to inhibit bone resorption. Although PPi was unable to do this, BPs turned out to be remarkably effective inhibitors of bone resorption, both in vitro and in vivo experimental systems, and eventually in humans. As ever more potent BPs were synthesised and studied, it became apparent that physico-chemical effects were insufficient to explain their biological effects, and that cellular actions must be involved. Despite many attempts, it was not until the 1990s that their biochemical actions were elucidated. It is now clear that bisphosphonates inhibit bone resorption by being selectively taken up and adsorbed to mineral surfaces in bone, where they interfere with the action of the bone-resorbing osteoclasts. Bisphosphonates are internalised by osteoclasts and interfere with specific biochemical processes. Bisphosphonates can be classified into at least two groups with different molecular modes of action. The simpler non-nitrogen containing bisphosphonates (such as etidronate and clodronate) can be metabolically incorporated into non-hydrolysable analogues of ATP, which interfere with ATP-dependent intracellular pathways. The more potent, nitrogen-containing bisphosphonates (including pamidronate, alendronate, risedronate, ibandronate and zoledronate) are not metabolised in this way but inhibit key enzymes of the mevalonate/cholesterol biosynthetic pathway. The major enzyme target for bisphosphonates is farnesyl pyrophosphate synthase (FPPS), and the crystal structure elucidated for this enzyme reveals how BPs bind to and inhibit at the active site via their critical N atoms. Inhibition of FPPS prevents the biosynthesis of isoprenoid compounds (notably farnesol and geranylgeraniol) that are required for the post-translational prenylation of small GTP-binding proteins (which are also GTPases) such as rab, rho and rac, which are essential for intracellular signalling events within osteoclasts. The accumulation of the upstream metabolite, isopentenyl pyrophosphate (IPP), as a result of inhibition of FPPS may be responsible for immunomodulatory effects on gamma delta (γδ) T cells, and can also lead to production of another ATP metabolite called ApppI, which has intracellular actions. Effects on other cellular targets, such as osteocytes, may also be important. Over the years many hundreds of BPs have been made, and more than a dozen have been studied in man. As reviewed elsewhere in this issue, bisphosphonates are established as the treatments of choice for various diseases of excessive bone resorption, including Paget's disease of bone, the skeletal complications of malignancy, and osteoporosis. Several of the leading BPs have achieved 'block-buster' status with annual sales in excess of a billion dollars. As a class, BPs share properties in common. However, as with other classes of drugs, there are obvious chemical, biochemical, and pharmacological differences among the various BPs. Each BP has a unique profile in terms of mineral binding and cellular effects that may help to explain potential clinical differences among the BPs. Even though many of the well-established BPs have come or are coming to the end of their patent life, their use as cheaper generic drugs is likely to continue for many years to come. Furthermore in many areas, e.g. in cancer therapy, the way they are used is not yet optimised. New 'designer' BPs continue to be made, and there are several interesting potential applications in other areas of medicine, with unmet medical needs still to be fulfilled. The adventure that began in Davos more than 40 years ago is not yet over.

Bisphosphonate effects on bone turnover, microdamage, and mechanical properties: what we think we know and what we know that we don't know

The bisphosphonates (BPs) have been useful tools in our understanding of the role that bone remodeling plays in skeletal health. The purpose of this paper is to outline what we know, and what is still unknown, about the role that BPs play in modulating bone turnover, how this affects microdamage accumulation, and ultimately what the effects of these changes elicited by BPs are to the structural and the material biomechanical properties of the skeleton. We know that BPs suppress remodeling site-specifically, probably do not have a direct effect on formation, and that the individual BPs vary with respect to speed of onset, duration of effect and magnitude of suppression. However, we do not know if these differences are meaningful in a clinical sense, how much remodeling is sufficient, the optimal duration of treatment, or how long it takes to restore remodeling to pre-treatment levels following withdrawal. We also know that suppression is intimately tied to microdamage accumulation, which is also site-specific, that BPs impair targeted repair of damage, and that they can reduce the energy absorption capacity of bone at the tissue level. However, the BPs are clearly effective at preventing fracture, and generally increase bone mineral density and whole bone strength, so we do not know whether these changes in damage accumulation and repair, or the mechanical effects at the tissue level, are clinically meaningful. The mechanical effects of BPs on the fatigue life of bone, or BP effects on bone subject to an impact, are entirely unknown. This paper reviews the literature on these topics, and identifies gaps in knowledge that can be addressed with further research.

Calcium supplementation: balancing the cardiovascular risks

Calcium supplementation has been widely accepted as a key strategy in the prevention and treatment of osteoporosis. Its role has been undermined, to some extent, by its disappointing effects on fracture in randomised controlled trials, but its use has continued to be encouraged on the grounds that it is physiologically appealing, and is unlikely to cause harm. The latter assumption is now under threat from accumulating evidence that calcium supplement use is associated with an increased risk of myocardial infarction and, possibly, stroke. The latest data, based on meta-analysis of trials involving 29,000 participants, indicate that this risk is not mitigated by co-administration of vitamin D, and that the number of cardiovascular events caused is likely to be greater than the number of fractures prevented. These findings indicate that calcium supplementation probably does not have a role as a routine preventative agent and that dietary advice is the appropriate way to attain an adequate calcium intake in most situations. Patients at high risk of fracture need to take interventions of proven anti-fracture efficacy. Available evidence suggests that this efficacy is not dependent on the co-administration of calcium supplements.