Comparative Efficacy of Bisphosphonates to Prevent Fracture in Men with Osteoporosis: A Systematic Review with Network Meta-Analyses

Role and Regulation of Transcription Factors in Osteoclastogenesis

Bones serve mechanical and defensive functions, as well as regulating the balance of calcium ions and housing bone marrow.. The qualities of bones do not remain constant. Instead, they fluctuate throughout life, with functions increasing in some situations while deteriorating in others. The synchronization of osteoblast-mediated bone formation and osteoclast-mediated bone resorption is critical for maintaining bone mass and microstructure integrity in a steady state. This equilibrium, however, can be disrupted by a variety of bone pathologies. Excessive osteoclast differentiation can result in osteoporosis, Paget's disease, osteolytic bone metastases, and rheumatoid arthritis, all of which can adversely affect people's health. Osteoclast differentiation is regulated by transcription factors NFATc1, MITF, C/EBPα, PU.1, NF-κB, and c-Fos. The transcriptional activity of osteoclasts is largely influenced by developmental and environmental signals with the involvement of co-factors, RNAs, epigenetics, systemic factors, and the microenvironment. In this paper, we review these themes in regard to transcriptional regulation in osteoclastogenesis.

Fracture risk reduction and safety by osteoporosis treatment compared with placebo or active comparator in postmenopausal women: systematic review, network meta-analysis, and meta-regression analysis of randomised clinical trials

OBJECTIVE

To review the comparative effectiveness of osteoporosis treatments, including the bone anabolic agents, abaloparatide and romosozumab, on reducing the risk of fractures in postmenopausal women, and to characterise the effect of antiosteoporosis drug treatments on the risk of fractures according to baseline risk factors.

DESIGN

Systematic review, network meta-analysis, and meta-regression analysis of randomised clinical trials.

DATA SOURCES

Medline, Embase, and Cochrane Library to identify randomised controlled trials published between 1 January 1996 and 24 November 2021 that examined the effect of bisphosphonates, denosumab, selective oestrogen receptor modulators, parathyroid hormone receptor agonists, and romosozumab compared with placebo or active comparator.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials that included non-Asian postmenopausal women with no restriction on age, when interventions looked at bone quality in a broad perspective. The primary outcome was clinical fractures. Secondary outcomes were vertebral, non-vertebral, hip, and major osteoporotic fractures, all cause mortality, adverse events, and serious cardiovascular adverse events.

RESULTS

The results were based on 69 trials (>80 000 patients). For clinical fractures, synthesis of the results showed a protective effect of bisphosphonates, parathyroid hormone receptor agonists, and romosozumab compared with placebo. Compared with parathyroid hormone receptor agonists, bisphosphonates were less effective in reducing clinical fractures (odds ratio 1.49, 95% confidence interval 1.12 to 2.00). Compared with parathyroid hormone receptor agonists and romosozumab, denosumab was less effective in reducing clinical fractures (odds ratio 1.85, 1.18 to 2.92 for denosumab v parathyroid hormone receptor agonists and 1.56, 1.02 to 2.39 for denosumab v romosozumab). An effect of all treatments on vertebral fractures compared with placebo was found. In the active treatment comparisons, denosumab, parathyroid hormone receptor agonists, and romosozumab were more effective than oral bisphosphonates in preventing vertebral fractures. The effect of all treatments was unaffected by baseline risk indicators, except for antiresorptive treatments that showed a greater reduction of clinical fractures compared with placebo with increasing mean age (number of studies=17; β=0.98, 95% confidence interval 0.96 to 0.99). No harm outcomes were seen. The certainty in the effect estimates was moderate to low for all individual outcomes, mainly because of limitations in reporting, nominally indicating a serious risk of bias and imprecision.

CONCLUSIONS

The evidence indicated a benefit of a range of treatments for osteoporosis in postmenopausal women for clinical and vertebral fractures. Bone anabolic treatments were more effective than bisphosphonates in the prevention of clinical and vertebral fractures, irrespective of baseline risk indicators. Hence this analysis provided no clinical evidence for restricting the use of anabolic treatment to patients with a very high risk of fractures.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019128391.

Male osteoporosis

Osteoporosis, a disease classically attributed to postmenopausal women, is underappreciated, underdiagnosed, and undertreated in men. However, it is not uncommon for osteoporotic fractures to occur in men. About 40% of fractures occur in men with an incidence that has increased over the years. After a first fracture, the risk of a subsequent episode, as well as the risk of death, is higher in the male than in the female population. Despite these facts, only 10% of men with osteoporosis receive adequate treatment. Up to half of the cases of male osteoporosis have a secondary cause, the most common being hypogonadism, excessive alcohol consumption, and chronic use of glucocorticoids. The International Society for Clinical Densitometry (ISCD) recommends using the female database for the diagnosis of osteoporosis by DXA (T-score ≤ -2.5 in men over 50 years old). In addition, osteoporosis can also be diagnosed independently of the BMD if a fragility fracture is present, or if there is a high risk of fractures by FRAX. Treatment is similar to postmenopausal osteoporosis, because the data regarding changes in bone density track closely to those in women. Data concerning fracture risk reduction are not as certain because the clinical trials have included fewer subjects for shorter period of time. In men with symptomatic hypogonadism, testosterone replacement, if indicated, can improve BMD.

The Effects of Trends in Osteoporosis Treatment on the Incidence of Fractures

OBJECTIVE

This study focused on the trends in antiosteoporosis drug preferences and compared the incidence of fractures between patients treated orally and those who were exposed to an awareness campaign and assigned to intravenous/subcutaneous treatment.

METHODS

Our hospital registry included 1,716 osteoporotic women who were over 65 years of age without preexisting vertebral and nonvertebral fractures over 1 year before this study, with bone mineral density (BMD) < -2.5 standard deviation (SD) and fracture assessment tool (FRAX) score > 20%, who were given 1,337 oral and 379 intravenous/subcutaneous prescriptions to treat their osteoporosis. Self-administered surveys (2012, 2013, 2014, 2015, and 2016) collected data on trends of preferences among nine drugs and fracture prevention using relative risk reduction (RRR).

RESULTS

The number of patients taking oral prescriptions decreased gradually from 2012 to 2016, while the number of patients treated with intravenous and subcutaneous injections increased. The incidence of fracture was lower in patients receiving intravenous and subcutaneous injections than in patients taking oral medications.

CONCLUSION

These findings indicate a decrease in oral prescriptions for osteoporosis treatment and that treatment for osteoporosis using intravenous or subcutaneous injections of antiosteoporosis drugs is more effective for preventing fractures.

Molecular Mechanisms and Emerging Therapeutics for Osteoporosis

Osteoporosis is the most common chronic metabolic bone disease. It has been estimated that more than 10 million people in the United States and 200 million men and women worldwide have osteoporosis. Given that the aging population is rapidly increasing in many countries, osteoporosis could become a global challenge with an impact on the quality of life of the affected individuals. Osteoporosis can be defined as a condition characterized by low bone density and increased risk of fractures due to the deterioration of the bone architecture. Thus, the major goal of treatment is to reduce the risk for fractures. There are several treatment options, mostly medications that can control disease progression in risk groups, such as postmenopausal women and elderly men. Recent studies on the basic molecular mechanisms and clinical implications of osteoporosis have identified novel therapeutic targets. Emerging therapies targeting novel disease mechanisms could provide powerful approaches for osteoporosis management in the future. Here, we review the etiology of osteoporosis and the molecular mechanism of bone remodeling, present current pharmacological options, and discuss emerging therapies targeting novel mechanisms, investigational treatments, and new promising therapeutic approaches.

The biology of vascular calcification

Vascular calcification (VC), characterized by different mineral deposits (i.e., carbonate apatite, whitlockite and hydroxyapatite) accumulating in blood vessels and valves, represents a relevant pathological process for the aging population and a life-threatening complication in acquired and in genetic diseases. Similarly to bone remodeling, VC is an actively regulated process in which many cells and molecules play a pivotal role. This review aims at: (i) describing the role of resident and circulating cells, of the extracellular environment and of positive and negative factors in driving the mineralization process; (ii) detailing the types of VC (i.e., intimal, medial and cardiac valve calcification); (iii) analyzing rare genetic diseases underlining the importance of altered pyrophosphate-dependent regulatory mechanisms; (iv) providing therapeutic options and perspectives.

Association of Bisphosphonate Therapy With Incident of Lower Extremity Fractures in Persons With Spinal Cord Injuries or Disorders

OBJECTIVE

To investigate the association between prescriptions for bisphosphonates; calcium and vitamin D supplements; and receipt of dual-energy x-ray absorptiometry (DXA) screening, and incident fracture risk in men and women with a spinal cord injury (SCI) or disorder (SCID).

DESIGN

Propensity-matched case-control analyses.

SETTING

United States Veterans Affairs (VA) facilities.

PARTICIPANTS

A total of 7989 men and 849 women with an SCID included in VA administrative databases between October 1, 2005 and October 1, 2015 were identified (N=8838). Cases included 267 men and 59 women with a bisphosphonate prescription propensity matched with up to 4 controls.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Incident lower extremity fractures.

RESULTS

There was no significant association between prescriptions for bisphosphonates and incident lower extremity fractures in men (odds ratio [OR], 1.04; 95% confidence interval [CI], 0.62-1.77) or women (OR, 1.02; 95% CI, 0.28-3.75). In men, similar null associations were seen among those who were adherent to bisphosphonate therapy (OR, 1.25; 95% CI, 0.73-2.16), were concomitant users of vitamin D and calcium and a bisphosphonate (OR, 1.05; 95% CI, 0.57-1.96), had more than 1 fracture on different dates during the study period (OR, 0.13; 95% CI, 0.02-1.16) and in those who had undergone DXA testing prior to the date of the bisphosphonate prescription and incident fracture (OR, 1.26; 95% CI, 0.69-2.32).

CONCLUSIONS

In men with a traumatic SCI and women with a traumatic SCID, bisphosphonate therapies for osteoporosis do not appear to significantly affect fracture risk. Adequately powered randomized controlled trials are needed to definitively demonstrate efficacy of bisphosphonates for fracture prevention in this population. There is a compelling need to identify new medications to prevent fractures in this high-risk population.

Molecular-Based Treatment Strategies for Osteoporosis: A Literature Review

Osteoporosis is an unavoidable public health problem in an aging or aged society. Anti-resorptive agents (calcitonin, estrogen, and selective estrogen-receptor modulators, bisphosphonates, anti-receptor activator of nuclear factor κB ligand antibody along with calcium and vitamin D supplementations) and anabolic agents (parathyroid hormone and related peptide analogs, sclerostin inhibitors) have major roles in current treatment regimens and are used alone or in combination based on the pathological condition. Recent advancements in the molecular understanding of bone metabolism and in bioengineering will open the door to future treatment paradigms for osteoporosis, including antibody agents, stem cells, and gene therapies. This review provides an overview of the molecular mechanisms, clinical evidence, and potential adverse effects of drugs that are currently used or under development for the treatment of osteoporosis to aid clinicians in deciding how to select the best treatment option.

Pharmacological and Non-pharmacological Means for Prevention of Fractures among Elderly

Fractures are major cause of morbidity, mortality, and healthcare and social services expenditure in elderly. Fractures often have multifactorial etiologies and the condition emerges due to the interaction between the different predisposing and precipitating factors. One of the most common causes leading to fractures after minimal trauma in older people is osteoporosis. The objective of this article is to describe the clinical concept and summarize the evidence and to explain the future directions for research, focusing on specific issues related to prevent fracture in the elderly. This study reviewed the scientific literature addressing strategies for primary and secondaryprevention of fractures among elderly in the context of pharmacological and non-pharmacological means. A growing body of scientific evidence supports the use of both non-pharmacological and pharmacological interventions for the prevention of fracture. Research on these interventions has yielded positive outcomes in fracture rates. The bisphosphonates and vitamin D and calcium suppliments are the preferred therapy for prevention of osteoporotic fractures. Weight-bearing exercise and reducing home hazards have beneficial effects in reducing the incidence of falls and consequently reduce fractures. Prevention of fractures in elderly consists of therapy and prevention of osteoporosis, fall prevention, and using injury-site protection by high-risk elderly patients. Special consideration needs to be taken to reduce home hazard, and falls prevention education can be recommended to the elderly with history of fall or mobility limitations. Future research to prevent fractures in elderly population should not only concentrate on improving bone density and strength but also need to be focused on falls reduction strategies.

The guiding role of bone metabolism test in osteoporosis treatment

Osteoporosis (OP) and osteoporotic fractures are becoming a serious health care issue in the world. Calcium and vitamin D are the basic treatment for osteoporosis. Nonetheless, they do not effectively reduce the incidences of fracture. Currently approved treatments for osteoporosis include selective estrogen receptor modulators (SERMs), bisphosphonates, denosumab, teriparatide, calcitonin and others. However, the appearance of some adverse effects including atypical fracture and breast cancer has limited long-term treatments above mentioned. Therefore, treatment decision should be made on an individual basis, taking into account the relative benefits and risks in different patients. Bone metabolism test helps to assess the patient's condition, which may ultimately lead to therapeutic options and better clinical outcomes.

Comparison of fracture risk assessment tools in older men without prior hip or spine fracture: the MrOS study

Femoral neck bone mineral density (BMD), age plus femoral neck BMD T score, and three externally generated fracture risk tools had similar accuracy to identify older men who developed osteoporotic fractures. Risk tools with femoral neck BMD performed better than those without BMD. The externally developed risk tools were poorly calibrated.

INTRODUCTION

We compared the performance of fracture risk assessment tools in older men, accounting for competing risks including mortality.

METHODS

A comparative ROC curve analysis assessed the ability of the QFracture, FRAX® and Garvan fracture risk tools, and femoral neck bone mineral density (BMD) T score with or without age to identify incident fracture in community-dwelling men aged 65 years or older (N = 4994) without hip or clinical vertebral fracture or antifracture treatment at baseline.

RESULTS

Among risk tools calculated with BMD, the discriminative ability to identify men with incident hip fracture was similar for FRAX (AUC 0.77, 95% CI 0.73, 0.81), the Garvan tool (AUC 0.78, 95% CI 0.74, 0.82), age plus femoral neck BMD T score (AUC 0.79, 95% CI 0.75, 0.83), and femoral neck BMD T score alone (AUC 0.76, 95% CI 0.72, 0.81). Among risk tools calculated without BMD, the discriminative ability to identify hip fracture was similar for QFracture (AUC 0.69, 95% CI 0.66, 0.73), FRAX (AUC 0.70, 95% CI 0.66, 0.73), and the Garvan tool (AUC 0.71, 95% CI 0.67, 0.74). Correlated ROC curve analyses revealed better diagnostic accuracy for risk scores calculated with BMD compared with QFracture (P < 0.0001). Calibration was good for the internally generated BMD T score predictor with or without age and poor for the externally developed risk tools.

CONCLUSION

In untreated older men without fragility fractures at baseline, an age plus femoral neck BMD T score classifier identified men with incident hip fracture as accurately as more complicated fracture risk scores.

Sequential treatment with zoledronic acid followed by teriparatide or vice versa increases bone mineral density and bone strength in ovariectomized rats

Bisphosphonates (BPs) and teriparatide (TPTD) are both effective treatments for osteoporosis, but BP treatment prior to daily TPTD treatment has been shown to impair the effect of TPTD in some clinical studies. In contrast, the loss of bone mineral density (BMD) that occurs after withdrawal of TPTD can be prevented by BP treatment. Although various studies have investigated the combination and/or sequential use of BP and TPTD, there have been no clinical studies investigating sequential treatment with zoledronic acid (ZOL) and TPTD (or vice versa). In this study, we evaluated the effects of sequential treatment with TPTD followed by ZOL, and ZOL followed by TPTD, using ovariectomized (OVX) rats. Two months after OVX, osteopenic rats were treated with ZOL, TPTD, or vehicle for a period of 4 months (first treatment period), and then the treatments were switched and administered for another 4 months (second treatment period). The group treated with ZOL followed by TPTD showed an immediate increase in BMD of the proximal tibia and greater BMD and bone strength of the lumbar vertebral body, femoral diaphysis, and proximal femur than the group treated with ZOL followed by vehicle. Serum osteocalcin, a marker of bone formation, increased rapidly after switching to TPTD from ZOL. The group treated with TPTD followed by ZOL did not lose BMD in the proximal tibia after TPTD was stopped, while the group treated with TPTD followed by vehicle did lose BMD. The BMD and bone strength of the lumbar vertebral body, femoral diaphysis, and proximal femur were greater in the group treated with TPTD followed by ZOL than in the group treated with TPTD followed by vehicle. The increase in serum osteocalcin and urinary CTX after withdrawal of TPTD was prevented by the switch from TPTD to ZOL. In conclusion, our results demonstrate that switching from ZOL to TPTD resulted in a non-attenuated anabolic response in the lumbar spine and femur of OVX rats. In addition, switching from TPTD to ZOL caused BMD to be maintained or further increased. If these results can be reproduced in a clinical setting, the sequential use of ZOL followed by TPTD or vice versa in the treatment of osteoporosis patients would contribute to increases in BMD that, hopefully, would translate into a corresponding decrease in the incidence of vertebral and non-vertebral fractures.

The Efficacy of Bisphosphonates for Prevention of Osteoporotic Fracture: An Update Meta-analysis

BACKGROUND

The efficacy of bisphosphonates for osteoporotic fracture has been consistently reported in recent randomized controlled trials (RCTs) enrolling hundreds of patients. The objective of this study was to update knowledge on the efficacy of available bisphosphonates in the prevention of vertebral and non-vertebral fractures.

METHODS

An approach "using systematic reviews" on PubMed and Cochrane Library was taken. Twenty-four RCTs investigating the effects of bisphosphonates for the prevention of osteoporotic fracture were included in final analysis. A pairwise meta-analysis was conducted with a random effects model. Subgroup analysis was performed according to the type of bisphosphonate.

RESULTS

The use of bisphosphonate decrease the risk of overall osteoporotic fracture (odds ratio [OR] 0.62; P<0.001), vertebral fracture (OR 0.55; P<0.001) and non-vertebral fracture (OR 0.73; P<0.001). Subgroup analysis indicated that zoledronic acid showed the lowest risk reduction (OR 0.61; P<0.001) for overall osteoporotic fractures but no significance was observed for etidronate (OR 0.34; P=0.127).

CONCLUSIONS

This update meta-analysis re-confirmed that bisphosphonate use can effectively reduce the risk of osteoporotic fracture. However, there is a lack of evidence regarding etidronate for the prevention of osteoporotic fracture.