Nonvertebral fracture risk reduction with nitrogen-containing bisphosphonates

Reduced Bone Loss Is Associated With Reduced Mortality Risk in Subjects Exposed to Nitrogen Bisphosphonates: A Mediation Analysis

Bisphosphonates, potent antiresorptive agents, have been found to be associated with mortality reduction. Accelerated bone loss is, in itself, an independent predictor of mortality risk, but the relationship between bisphosphonates, bone loss, and mortality is unknown. This study aimed to determine whether the association between bisphosphonates and mortality is mediated by a reduction in the rate of bone loss. Participants from the population-based Canadian Multicentre Osteoporosis Study were followed prospectively between1996 and 2011. Comorbidities and lifestyle factors were collected at baseline and bone mineral density (BMD) at baseline and at years 3 (for those aged 40 to 60 years), 5, and 10. Rate of bone loss was calculated using linear regression. Information on medication use was obtained yearly. Bisphosphonate users grouped into nitrogen bisphosphonates (nBP; alendronate or risedronate) and etidronate and non-users (NoRx) were matched by propensity score, including all baseline factors as well as time of treatment. Cox's proportional hazards models, unadjusted and adjusted for annual rate of bone loss, were used to determine the association between nBP and etidronate versus NoRx. For the treatment groups with significant mortality risk reduction, the percent of mortality reduction mediated by a reduction in the rate of bone loss was estimated using a causal mediation analysis. There were 271 pairs of nBP and matched NoRx and 327 pairs of etidronate and matched NoRx. nBP but not etidronate use was associated with significant mortality risk reduction (hazard ratios [HR] = 0.61 [95% confidence interval 0.39-0.96] and 1.35 [95% CI 0.86-2.11] for nBP and etidronate, respectively). Rapid bone loss was associated with more than 2-fold increased mortality risk compared with no loss. Mediation analysis indicated that 39% (95% CI 7%-84%) of the nBP association with mortality was related to a reduction in the rate of bone loss. This finding provides an insight into the mechanism of the relationship between nBP and survival benefit in osteoporotic patients. © 2019 American Society for Bone and Mineral Research.

Impact of bisphosphonate compliance on the risk of osteoporotic fracture in France

Limited information is available on the impact of bisphosphonate compliance levels on fracture risk in osteoporosis patients in France. The results of this nested case-control, retrospective study suggest that fracture risk did not significantly change with bisphosphonate compliance levels, except for highly compliant patients.

PURPOSE/INTRODUCTION

This was the first study conducted in France to evaluate the impact of compliance levels for bisphosphonates, the most frequently prescribed first-line anti-osteoporotic treatment, on fracture risk.

METHODS

This retrospective nested case-control study included patients ≥ 50 years old, who were recorded in a random sample of French claims data, did not die between 2006 and 2013, and received ≥ 1 reimbursement for anti-osteoporotic treatment between 2007 and 2013. Cases (patients hospitalised for osteoporosis-related fractures) were matched to 1-3 controls (patients hospitalised for other reasons). Patients hospitalised for fractures within 12 months preceding the first delivery of anti-osteoporotic treatment or during the first 24 months of follow-up were excluded. Bisphosphonate compliance during the 24 months preceding hospitalisation was calculated by the Continuous measure of Medication Acquisition version 7 (CMA7). We evaluated the impact of bisphosphonate compliance (CMA7 ≥ 80%) and very good compliance levels (CMA7 > 90%) on fracture risk.

RESULTS

In the main analysis, the mean CMA7 values during the 24 months preceding hospitalisation were 48.4% for the 434 cases and 51.3% for the 1123 age-matched controls. An adjusted conditional logistic regression showed no significant impact (odds ratio: 0.851 [95% confidence interval: 0.668, 1.084]) of bisphosphonate compliance on fracture occurrence. In the sensitivity analysis, including one randomly selected control per case and only controls with CMA7 values > 90%, occurrence of fractures was lower (odds ratio: 0.741 [95% confidence interval: 0.608, 0.903]) among the 119 controls.

CONCLUSION

In conclusion, this study suggested that very high levels of compliance with bisphosphonates are necessary to induce significant decreases in fracture risk.

Bazedoxifene: the evolving role of third-generation selective estrogen-receptor modulators in the management of postmenopausal osteoporosis

Osteoporosis is a significant public health concern, particularly for postmenopausal women. Current treatment options may not be appropriate for all women. Selective estrogen-receptor modulators (SERMs) are a class of molecules with tissue-selective activity. Bazedoxifene is currently in clinical development for the prevention and treatment of postmenopausal osteoporosis. In a 2-year, phase III, osteoporosis prevention study (N = 1583), bazedoxifene 10, 20, and 40 mg was shown to preserve bone mineral density and decrease biochemical markers of bone turnover compared with placebo in postmenopausal women at risk for osteoporosis. In a pivotal 3-year, phase III, osteoporosis treatment study (N = 7492), bazedoxifene 20 and 40 mg significantly reduced the incidence of new vertebral fractures compared with placebo (p < 0.05 for both) in postmenopausal women with osteoporosis. In a post hoc subgroup analysis of women at higher risk for fracture (n = 1772), bazedoxifene 20 mg significantly reduced the risk of nonvertebral fractures versus placebo (p = 0.02) and raloxifene 60 mg (p = 0.05). Bazedoxifene 20 mg has demonstrated sustained efficacy in reducing the risk of vertebral fractures over 5 and 7 years. Overall, bazedoxifene was generally safe and well tolerated, with favorable endometrial and breast safety profiles. As with other SERMs, the rate of deep vein thrombosis was higher in the bazedoxifene groups compared with placebo at 3 and 5 years. Considering its demonstrated efficacy and safety, bazedoxifene may be an appropriate osteoporosis therapy for women who cannot take or are unwilling to take bisphosphonates because of safety or tolerability issues. Bazedoxifene may also be appropriate for younger women at increased fracture risk who are concerned about the effects of long-term bisphosphonate therapy. This article reviews the results of key clinical trials of bazedoxifene for the prevention and treatment of postmenopausal osteoporosis and describes its role in clinical practice.

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.

Treatment of osteoporosis with annual iv zoledronic acid: effects on hip fracture

BACKGROUND

Several treatments for postmenopausal osteoporosis have been available in the past decade, but adherence to these treatments has been judged inadequate. The prevention of hip fracture by these medications is still modest.

METHODS

A literature search was performed for treatment with zoledronic acid for the prevention of hip fracture.

RESULTS

In the The Health Outcomes and Reduced Incidence with Zoledronic Acid Once Yearly (HORIZON) Pivotal Fracture Trial, involving 7765 postmenopausal women with low bone mineral density or with prevalent vertebral fracture, women taking zoledronic acid had a 41% relative risk reduction for hip fracture, at 3 years, compared to placebo. In the HORIZON Recurrent Fracture Trial, 2127 patients (76% were women) were randomized to receive either zoledronic acid or placebo after sustaining a first hip fracture. A reduction of 30% in the second hip fracture risk was observed, but it did not reach statistical significance. Zoledronic acid was generally safe in these trials, although a slightly increased rate of severe atrial fibrillations was observed in the HORIZON Prevention Fracture Trial, but not in the HORIZON Recurrent Fracture Trial.

CONCLUSION

Yearly zoledronic acid reduces the risk of hip fracture, both in postmenopausal osteoporotic women with and without prevalent vertebral fracture and in men and women with a recent first hip fracture.