Effects of alendronate and risedronate on bone mineral density and bone turnover markers in late postmenopausal women with osteoporosis

Vitamin D and calcium supplementation in women undergoing pharmacological management for postmenopausal osteoporosis: a level I of evidence systematic review

The present systematic review investigates whether different doses of vitamin D and calcium supplementation in women with postmenopausal osteoporosis undergoing antiresorptive therapy have an association with BMD (spine, hip, femur neck), serum markers of osteoporosis (bone-ALP, NTX, CTX), the rate of pathological vertebral and non-vertebral fractures, adverse events, and mortality. This systematic review was conducted according to the PRISMA 2020 guidelines. PubMed, Google Scholar, Embase, and Scopus databases were accessed in September 2024. All randomised clinical trials (RCTs) comparing two or more treatments for postmenopausal osteoporosis supplemented with vitamin D and/or calcium were accessed. Only studies that indicated daily vitamin D and/or calcium supplementation doses were accessed. Data from 37 RCTs (43,397 patients) were retrieved. Patients received a mean of 833.6 ± 224.0 mg and 92.8 ± 228.7 UI of calcium and vitamin D supplementation, respectively. The mean length of the follow-up was 25.8 ± 13.3 months. The mean age of the patients was 66.4 ± 5.6 years, and the mean BMI was 25.2 ± 1.6 kg/m2. There was evidence of a statistically significant negative association between daily vitamin D supplementation and gastrointestinal adverse events (r = - 0.5; P = 0.02) and mortality (r = - 0.7; P = 0.03). No additional statistically significant associations were evidenced. In postmenopausal women who undergo antiresorptive treatment for osteoporosis, vitamin D was associated with a lower frequency of gastrointestinal adverse events and mortality. Calcium supplementation did not evidence an association with any of the endpoints of interest.Level of evidence Level I, systematic review of RCTs.

Effects of resistance training on microcirculation of bone tissue and bone turnover markers in postmenopausal women with osteopenia or osteoporosis: A systematic review

After menopause, there is an imbalance between bone formation and resorption activity, which could lead to postmenopausal osteopenia or osteoporosis. Resistance training (RT) can induce mechanical stress on bone which is necessary for bone remodeling and angiogenic-osteogenic response. This systematic review aims to assess the effects of RT on bone microcirculation and bone turnover markers (BTMs) in postmenopausal women with osteopenia or osteoporosis. We conducted a comprehensive search for related studies published up to April 2023 to identify eligible articles. Out of 316 articles identified, the full texts of 69 articles were screened. There is not any study which consider the effect of resistance exercises on bone microcirculation in PMOP women, but four articles aseess the effect of RT on BTMs and were reviewed. The quality of the articles was assessed by using the Physiotherapy Evidence Database (PEDro) scale. In one study, after 6- and 12 -months RT, bone formation and bone resorption biomarkers decreased not significantly. According to another study, bone formation and resorption biomarkers increased significantly after 3-months RT. Two other studies reported increases in biomarkers of bone formation along with decreases of biomarkers in bone resorption after 6-months of RT, but these were not significant. However, these results suggest that RT had some beneficial effects on BTMs but it is not an effective tool for modifying BTMs in women with osteoporosis or osteopenia. This may be due to the site-specific skeletal stimulation that RT provides. In addition considering the effect of RT on microcirculation of bone are important . So, there is a need for further, high-quality studies in this field.

Alendronate for the primary and secondary prevention of osteoporotic fractures in postmenopausal women

RATIONALE

Osteoporosis is an abnormal reduction in bone mass and bone deterioration, leading to increased fracture risk. Alendronate belongs to the bisphosphonate class of drugs, which inhibit bone resorption by interfering with the activity of osteoclasts (bone cells that break down bone tissue). This is an update of a Cochrane review first published in 2008.

OBJECTIVES

To assess the benefits and harms of alendronate in the primary and secondary prevention of osteoporotic fractures in postmenopausal women at lower and higher risk of fracture, respectively.

SEARCH METHODS

We searched Evidence-Based Medicine Reviews (which includes CENTRAL), MEDLINE, Embase, two trial registers, drug approval agency websites, and the bibliographies of relevant systematic reviews to identify the studies included in this review. The latest search date was 01 February 2023. We imposed no restrictions on language, date, form of publication, or reported outcomes.

ELIGIBILITY CRITERIA

We included only randomized controlled trials that assessed the effects of alendronate on postmenopausal women. Targeted participants must have received at least one year of alendronate. We classified a study as secondary prevention if its population met one or more of the following hierarchical criteria: a diagnosis of osteoporosis, a history of vertebral fractures, a low bone mineral density T-score (-2.5 or lower), and 75 years old or older. If a study population met none of those criteria, we classified it as a primary prevention study.

OUTCOMES

Our major outcomes were clinical vertebral, non-vertebral, hip, and wrist fractures, withdrawals due to adverse events, and serious adverse events.

RISK OF BIAS

We used the Cochrane risk of bias 1 tool.

SYNTHESIS METHODS

We used standard methodological procedures expected by Cochrane. Based on the previous review experience, in which the clinical and methodological characteristics in the primary and secondary prevention studies were homogeneous, we used a fixed-effect model for meta-analysis and estimated effects using the risk ratio (RR) for dichotomous outcomes. Our base case analyses included all eligible placebo-controlled studies with usable data. We selected the data available for the longest treatment period. We consider a relative change exceeding 15% as clinically important.

INCLUDED STUDIES

We included 119 studies, of which 102 studies provided data for quantitative synthesis. Of these, we classified 34 studies (15,188 participants) as primary prevention and 68 studies (29,577 participants) as secondary prevention. We had concerns about risks of bias in most studies. Selection bias was the most frequently overlooked domain, with only 20 studies (19%) describing appropriate methods for both sequence generation and allocation concealment. Eight studies (8%) were at low risk of bias in all seven domains.

SYNTHESIS OF RESULTS

The base case analyses included 16 primary prevention studies (one to five years in length; 10,057 women) and 20 secondary prevention studies (one to three years in length; 7375 women) which compared alendronate 10 mg/day (or 70 mg/week) to placebo, no treatment, or both. Indirectness, imprecision, and risk of bias emerged as the main factors contributing to the downgrading of the certainty of the evidence. For primary prevention, alendronate may lead to a clinically important reduction in clinical vertebral fractures (16/1190 in the alendronate group versus 24/926 in the placebo group; RR 0.45, 95% confidence interval [CI] 0.25 to 0.84; absolute risk reduction [ARR] 1.4% fewer, 95% CI 1.9% fewer to 0.4% fewer; low-certainty evidence) and non-vertebral fractures (RR 0.83, 95% CI 0.72 to 0.97; ARR 1.6% fewer, 95% CI 2.6% fewer to 0.3% fewer; low-certainty evidence). However, clinically important differences were not observed for the following outcomes: hip fractures (RR 0.76, 95% CI 0.43 to 1.32; ARR 0.2% fewer, 95% CI 0.4% fewer to 0.2% more; low-certainty evidence); wrist fractures (RR 1.12, 95% CI 0.84 to 1.49; ARR 0.3% more, 95% CI 0.4% fewer to 1.1% more; low-certainty evidence); withdrawals due to adverse events (RR 1.03, 95% CI 0.89 to 1.18; ARR 0.2% more, 95% CI 0.9% fewer to 1.5% more; low-certainty evidence); and serious adverse events (RR 1.08, 95% CI 0.82 to 1.43; ARR 0.5% more, 95% CI 1.2% fewer to 2.8% more; low-certainty evidence). For secondary prevention, alendronate probably results in a clinically important reduction in clinical vertebral fractures (24/1114 in the alendronate group versus 51/1055 in the placebo group; RR 0.45, 95% CI 0.28 to 0.73; ARR 2.7% fewer, 95% CI 3.5% fewer to 1.3% fewer; moderate-certainty evidence). It may lead to a clinically important reduction in non-vertebral fractures (RR 0.80, 95% CI 0.64 to 0.99; ARR 2.8% fewer, 95% CI 5.1% fewer to 0.1% fewer; low-certainty evidence); hip fractures (RR 0.49, 95% CI 0.25 to 0.96; ARR 1.0% fewer, 95% CI 1.5% fewer to 0.1% fewer; low-certainty evidence); wrist fractures (RR 0.54, 95% CI 0.33 to 0.90; ARR 1.8% fewer, 95% CI 2.6% fewer to 0.4% fewer; low-certainty evidence); and serious adverse events (RR 0.75, 95% CI 0.59 to 0.96; ARR 3.5% fewer, 95% CI 5.8% fewer to 0.6% fewer; low-certainty evidence). However, the effects of alendronate for withdrawals due to adverse events are uncertain (RR 0.95, 95% CI 0.78 to 1.16; ARR 0.4% fewer, 95% CI 1.7% fewer to 1.3% more; very low-certainty evidence). Furthermore, the updated evidence for the safety risks of alendronate suggests that, irrespective of participants' risk of fracture, alendronate may lead to little or no difference for gastrointestinal adverse events. Zero incidents of osteonecrosis of the jaw and atypical femoral fracture were observed.

AUTHORS' CONCLUSIONS

For primary prevention, compared to placebo, alendronate 10 mg/day may reduce clinical vertebral and non-vertebral fractures, but it might make little or no difference to hip and wrist fractures, withdrawals due to adverse events, and serious adverse events. For secondary prevention, alendronate probably reduces clinical vertebral fractures, and may reduce non-vertebral, hip, and wrist fractures, and serious adverse events, compared to placebo. The evidence is very uncertain about the effect of alendronate on withdrawals due to adverse events.

FUNDING

This Cochrane review had no dedicated funding.

REGISTRATION

This review is an update of the previous review (DOI: 10.1002/14651858.CD001155).

Risedronate for the primary and secondary prevention of osteoporotic fractures in postmenopausal women

BACKGROUND

Osteoporosis is an abnormal reduction in bone mass and bone deterioration leading to increased fracture risk. Risedronate belongs to the bisphosphonate class of drugs which act to inhibit bone resorption by interfering with the activity of osteoclasts. This is an update of a Cochrane Review that was originally published in 2003.

OBJECTIVES

We assessed the benefits and harms of risedronate in the primary and secondary prevention of osteoporotic fractures for postmenopausal women at lower and higher risk for fractures, respectively.

SEARCH METHODS

With broader and updated strategies, we searched the Cochrane Central Register of Control Trials (CENTRAL), MEDLINE and Embase. A grey literature search, including the online databases ClinicalTrials.gov, International Clinical Trials Registry Platform (ICTRP), and drug approval agencies, as well as bibliography checks of relevant systematic reviews was also performed. Eligible trials published between 1966 to 24 March 2021 were identified.

SELECTION CRITERIA

We included randomised controlled trials that assessed the benefits and harms of risedronate in the prevention of fractures for postmenopausal women. Participants must have received at least one year of risedronate, placebo or other anti-osteoporotic drugs, with or without concurrent calcium/vitamin D. Major outcomes were clinical vertebral, non-vertebral, hip and wrist fractures, withdrawals due to adverse events, and serious adverse events. In the interest of clinical relevance and applicability, we classified a study as secondary prevention if its population fulfilled more than one of the following hierarchical criteria: a diagnosis of osteoporosis, a history of vertebral fractures, low bone mineral density (BMD)T score ≤ -2.5, and age ≥ 75 years old. If none of these criteria was met, the study was considered to be primary prevention.

DATA COLLECTION AND ANALYSIS

We used standard methodology expected by Cochrane. We pooled the relative risk (RR) of fractures using a fixed-effect model based on the expectation that the clinical and methodological characteristics of the respective primary and secondary prevention studies would be homogeneous, and the experience from the previous review suggesting that there would be a small number of studies. The base case included the data available for the longest treatment period in each placebo-controlled trial and a >15% relative change was considered clinically important. The main findings of the review were presented in summary of findings tables, using the GRADE approach. In addition, we looked at benefit and harm comparisons between different dosage regimens for risedronate and between risedronate and other anti-osteoporotic drugs.

MAIN RESULTS

Forty-three trials fulfilled the eligibility criteria, among which 33 studies (27,348 participants) reported data that could be extracted and quantitatively synthesized. We had concerns about particular domains of risk of bias in each trial. Selection bias was the most frequent concern, with only 24% of the studies describing appropriate methods for both sequence generation and allocation concealment. Fifty per cent and 39% of the studies reporting benefit and harm outcomes, respectively, were subject to high risk. None of the studies included in the quantitative syntheses were judged to be at low risk of bias in all seven domains. The results described below pertain to the comparisons for daily risedronate 5 mg versus placebo which reported major outcomes. Other comparisons are described in the full text. For primary prevention, low- to very low-certainty evidence was collected from four studies (one to two years in length) including 989 postmenopausal women at lower risk of fractures. Risedronate 5 mg/day may make little or no difference to wrist fractures [RR 0.48 ( 95% CI 0.03 to 7.50; two studies, 243 participants); absolute risk reduction (ARR) 0.6% fewer (95% CI 1% fewer to 7% more)] and withdrawals due to adverse events [RR 0.67 (95% CI 0.38 to 1.18; three studies, 748 participants); ARR 2% fewer (95% CI 5% fewer to 1% more)], based on low-certainty evidence. However, its preventive effects on non-vertebral fractures and serious adverse events are not known due to the very low-certainty evidence. There were zero clinical vertebral and hip fractures reported therefore the effects of risedronate for these outcomes are not estimable.  For secondary prevention, nine studies (one to three years in length) including 14,354 postmenopausal women at higher risk of fractures provided evidence. Risedronate 5 mg/day probably prevents non-vertebral fractures [RR 0.80 (95% CI 0.72 to 0.90; six studies, 12,173 participants); RRR 20% (95% CI 10% to 28%) and ARR 2% fewer (95% CI 1% fewer to 3% fewer), moderate certainty], and may reduce hip fractures [RR 0.73 (95% CI 0.56 to 0.94); RRR 27% (95% CI 6% to 44%) and ARR 1% fewer (95% CI 0.2% fewer to 1% fewer), low certainty]. Both of these effects are probably clinically important. However, risedronate's effects are not known for wrist fractures [RR 0.64 (95% CI 0.33 to 1.24); three studies,1746 participants); ARR 1% fewer (95% CI 2% fewer to 1% more), very-low certainty] and not estimable for clinical vertebral fractures due to zero events reported (low certainty). Risedronate results in little to no difference in withdrawals due to adverse events [RR 0.98 (95% CI 0.90 to 1.07; eight studies, 9529 participants); ARR 0.3% fewer (95% CI 2% fewer to 1% more); 16.9% in risedronate versus 17.2% in control, high certainty] and probably results in little to no difference in serious adverse events [RR 1.00 (95% CI 0.94 to 1.07; six studies, 9435 participants); ARR 0% fewer (95% CI 2% fewer to 2% more; 29.2% in both groups, moderate certainty).

AUTHORS' CONCLUSIONS

This update recaps the key findings from our previous review that, for secondary prevention, risedronate 5 mg/day probably prevents non-vertebral fracture, and may reduce the risk of hip fractures. We are uncertain on whether risedronate 5mg/day reduces clinical vertebral and wrist fractures.  Compared to placebo, risedronate probably does not increase the risk of serious adverse events.  For primary prevention, the benefit and harms of risedronate were supported by limited evidence with high uncertainty.

Pharmacological Management of Postmenopausal Osteoporosis: a Level I Evidence Based - Expert Opinion

Objectives: Postmenopausal osteoporosis carries a high risk of fractures, which decrease quality of life and are associated with high morbidity, mortality, and economic burden. The best pharmacological treatment options to manage and prevent osteoporotic fractures remain still unclear. The present study investigated the efficacy and safety of the most commonly employed drugs in the management of postmenopausal osteoporosis. Methods: Only RCTs comparing different drugs for the management of postmenopausal osteoporosis were included. Data from 76 RCTs (205,011 patients) were collected. The mean follow-up was 27.6 ± 14.9 months. Results: Denosumab reported the lowest rate of non-vertebral fractures (LOR -1.57), Romosozumab the lowest rate of vertebral fractures (LOR 1.99), and Ibandronate the lowest rate of hip fractures (LOR0.18). Serious adverse events resulted in the lowest in the Raloxifene group (LOR 3.11), while those leading to study discontinuation were lowest in the Romosozumab cohort (LOR 2.65). Conclusions: Denosumab resulted in most effective, particularly in reducing the occurrence of non-vertebral fractures. Romosozumab and Ibandronate resulted best to prevent, respectively, vertebral fractures and hip fractures. Adverse events leading to study discontinuation were less frequent in the Romosozumab and Denosumab groups, while Raloxifene and Alendronate showed a lower incidence of serious adverse events overall. Level of evidence: I, Bayesian network meta-analysis of RCTs.

Denosumab, raloxifene, romosozumab and teriparatide to prevent osteoporotic fragility fractures: a systematic review and economic evaluation

BACKGROUND

Fragility fractures are fractures that result from mechanical forces that would not ordinarily result in fracture.

OBJECTIVES

The objectives were to evaluate the clinical effectiveness, safety and cost-effectiveness of non-bisphosphonates {denosumab [Prolia®; Amgen Inc., Thousand Oaks, CA, USA], raloxifene [Evista®; Daiichi Sankyo Company, Ltd, Tokyo, Japan], romosozumab [Evenity®; Union Chimique Belge (UCB) S.A. (Brussels, Belgium) and Amgen Inc.] and teriparatide [Forsteo®; Eli Lilly and Company, Indianapolis, IN, USA]}, compared with each other, bisphosphonates or no treatment, for the prevention of fragility fracture.

DATA SOURCES

For the clinical effectiveness review, nine electronic databases (including MEDLINE, EMBASE and the World Health Organization International Clinical Trials Registry Platform) were searched up to July 2018.

REVIEW METHODS

A systematic review and network meta-analysis of fracture and femoral neck bone mineral density were conducted. A review of published economic analyses was undertaken and a model previously used to evaluate bisphosphonates was adapted. Discrete event simulation was used to estimate lifetime costs and quality-adjusted life-years for a simulated cohort of patients with heterogeneous characteristics. This was done for each non-bisphosphonate treatment, a strategy of no treatment, and the five bisphosphonate treatments previously evaluated. The model was populated with effectiveness evidence from the systematic review and network meta-analysis. All other parameters were estimated from published sources. An NHS and Personal Social Services perspective was taken, and costs and benefits were discounted at 3.5% per annum. Fracture risk was estimated from patient characteristics using the QFracture® (QFracture-2012 open source revision 38, Clinrisk Ltd, Leeds, UK) and FRAX® (web version 3.9, University of Sheffield, Sheffield, UK) tools. The relationship between fracture risk and incremental net monetary benefit was estimated using non-parametric regression. A probabilistic sensitivity analysis and scenario analyses were used to assess uncertainty.

RESULTS

Fifty-two randomised controlled trials of non-bisphosphonates were included in the clinical effectiveness systematic review and an additional 51 randomised controlled trials of bisphosphonates were included in the network meta-analysis. All treatments had beneficial effects compared with placebo for vertebral, non-vertebral and hip fractures, with hazard ratios varying from 0.23 to 0.94, depending on treatment and fracture type. The effects on vertebral fractures and the percentage change in bone mineral density were statistically significant for all treatments. The rate of serious adverse events varied across trials (0-33%), with most between-group differences not being statistically significant for comparisons with placebo/no active treatment, non-bisphosphonates or bisphosphonates. The incremental cost-effectiveness ratios were > £20,000 per quality-adjusted life-year for all non-bisphosphonate interventions compared with no treatment across the range of QFracture and FRAX scores expected in the population eligible for fracture risk assessment. The incremental cost-effectiveness ratio for denosumab may fall below £30,000 per quality-adjusted life-year at very high levels of risk or for high-risk patients with specific characteristics. Raloxifene was dominated by no treatment (resulted in fewer quality-adjusted life-years) in most risk categories.

LIMITATIONS

The incremental cost-effectiveness ratios are uncertain for very high-risk patients.

CONCLUSIONS

Non-bisphosphonates are effective in preventing fragility fractures, but the incremental cost-effectiveness ratios are generally greater than the commonly applied threshold of £20,000-30,000 per quality-adjusted life-year.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42018107651.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 29. See the NIHR Journals Library website for further project information.

A systematic review and economic evaluation of bisphosphonates for the prevention of fragility fractures

BACKGROUND

Fragility fractures are fractures that result from mechanical forces that would not ordinarily result in fracture.

OBJECTIVES

To evaluate the clinical effectiveness and safety of bisphosphonates [alendronic acid (Fosamax^® and Fosamax^® Once Weekly, Merck Sharp & Dohme Ltd), risedronic acid (Actonel^® and Actonel Once a Week^®, Warner Chilcott UK Ltd), ibandronic acid (Bonviva^®, Roche Products Ltd) and zoledronic acid (Aclasta^®, Novartis Pharmaceuticals UK Ltd)] for the prevention of fragility fracture and to assess their cost-effectiveness at varying levels of fracture risk.

DATA SOURCES

For the clinical effectiveness review, six electronic databases and two trial registries were searched: MEDLINE, EMBASE, The Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, Web of Science and BIOSIS Previews, Clinicaltrials.gov and World Health Organization International Clinical Trials Registry Platform. Searches were limited by date from 2008 until September 2014.

REVIEW METHODS

A systematic review and network meta-analysis (NMA) of effectiveness studies were conducted. A review of published economic analyses was undertaken and a de novo health economic model was constructed. Discrete event simulation was used to estimate lifetime costs and quality-adjusted life-years (QALYs) for each bisphosphonate treatment strategy and a strategy of no treatment for a simulated cohort of patients with heterogeneous characteristics. The model was populated with effectiveness evidence from the systematic review and NMA. All other parameters were estimated from published sources. A NHS and Personal Social Services perspective was taken, and costs and benefits were discounted at 3.5% per annum. Fracture risk was estimated from patient characteristics using the QFracture^® (QFracture-2012 open source revision 38, Clinrisk Ltd, Leeds, UK) and FRAX^® (web version 3.9, University of Sheffield, Sheffield, UK) tools. The relationship between fracture risk and incremental net benefit (INB) was estimated using non-parametric regression. Probabilistic sensitivity analysis (PSA) and scenario analyses were used to assess uncertainty.

RESULTS

Forty-six randomised controlled trials (RCTs) were included in the clinical effectiveness systematic review, with 27 RCTs providing data for the fracture NMA and 35 RCTs providing data for the femoral neck bone mineral density (BMD) NMA. All treatments had beneficial effects on fractures versus placebo, with hazard ratios varying from 0.41 to 0.92 depending on treatment and fracture type. The effects on vertebral fractures and percentage change in BMD were statistically significant for all treatments. There was no evidence of a difference in effect on fractures between bisphosphonates. A statistically significant difference in the incidence of influenza-like symptoms was identified from the RCTs for zoledronic acid compared with placebo. Reviews of observational studies suggest that upper gastrointestinal symptoms are frequently reported in the first month of oral bisphosphonate treatment, but pooled analyses of placebo-controlled trials found no statistically significant difference. A strategy of no treatment was estimated to have the maximum INB for patients with a 10-year QFracture risk under 1.5%, whereas oral bisphosphonates provided maximum INB at higher levels of risk. However, the PSA suggested that there is considerable uncertainty regarding whether or not no treatment is the optimal strategy until the QFracture score is around 5.5%. In the model using FRAX, the mean INBs were positive for all oral bisphosphonate treatments across all risk categories. Intravenous bisphosphonates were estimated to have lower INBs than oral bisphosphonates across all levels of fracture risk when estimated using either QFracture or FRAX.

LIMITATIONS

We assumed that all treatment strategies are viable alternatives across the whole population.

CONCLUSIONS

Bisphosphonates are effective in preventing fragility fractures. However, the benefit-to-risk ratio in the lowest-risk patients may be debatable given the low absolute QALY gains and the potential for adverse events. We plan to extend the analysis to include non-bisphosphonate therapies.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013006883.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Clinical effectiveness of bisphosphonates for the prevention of fragility fractures: A systematic review and network meta-analysis

OBJECTIVES

To assess the relative efficacy of bisphosphonates (alendronate, risedronate, ibandronate and zoledronic acid) for the treatment of osteoporosis using network meta-analysis (NMA).

METHODS

A systematic review of the literature was conducted using PRISMA guidelines. A network meta-analysis was used to determine the relative efficacy of treatments on four fracture outcomes (vertebral, non-vertebral, hip and wrist) and percentage change in femoral neck bone mineral density (BMD). Treatment effects were modelled using an exchangeable treatment effects model. Heterogeneity in treatment effects was explored by considering potential treatment effect modifiers using meta-regression. Where appropriate, inconsistency between direct and indirect evidence was assessed using node-splitting.

RESULTS

46 randomised controlled trials (RCTs) were identified. Twenty seven RCTs provided fracture data and 35 RCTs provided BMD data for analysis. Zoledronic acid was associated with the greatest treatment effect on vertebral fractures (HR 0.41, 95% CrI: 0.28, 0.56) and percentage change in BMD (3.21, 95%: CrI 2.52, 3.86) compared to placebo. The greatest treatment effect on non-vertebral and wrist fractures was given by risedronate (HR 0.72, 95%: CrI 0.53, 0.89 and HR 0.77, 95%: CrI 0.44, 1.24, respectively). For hip fractures the greatest treatment effect was given by alendronate (HR 0.78, 95% CrI: 0.44, 1.30).

CONCLUSIONS

All treatments examined were associated with beneficial effects on fractures and femoral neck BMD relative to placebo. For vertebral fractures and percentage change in femoral neck BMD the treatment effects were statistically significant for all treatments. Pairwise comparisons between treatments indicated that no active treatment was statistically significantly more effective than any other active treatment for fracture outcomes. There was some heterogeneity in treatment effects between studies suggesting differential treatment effects according to study characteristics; however, there was no evidence of differential treatment effects with respect to gender and age.

Homocysteine oxidative stress and relation to bone mineral density in post-menopausal osteoporosis

BACKGROUND AND AIMS

Mildly elevated homocysteine (Hcy) and oxidative stress are novel and potentially modifiable risk factors for post-menopausal osteoporosis. We hypothesized that imbalance of oxidant/ antioxidant status and increased Hcy concentration stimulates osteoporotic activity, leading to increased collagen I breakdown in post-menopausal women.

METHODS

Patients were divided into 2 groups (NOP and OP). Group NOP had normal bone mineral density (BMD) and group OP low BMD. Thirty-four (69%) were in group OP and 15 (31%) in group NOP. Serum Total Antioxidant Status (TAS) and Total Peroxide (TPx) levels were determined with new automated methods. The study included measurement of Deoxypyridinoline (DPD).

RESULTS

In OP patients plasma t-Hcy, urine deoxypyridinoline and plasma TPx were significantly higher than those in NOP controls. In addition, OP patients also had lower TAS levels than controls, which represent the oxidative imbalance. Pearson's correlation analysis revealed a negative correlation between t-Hcy and TAS (p<0.038). A significant negative correlation was also found between TAS level and BMD values for the spine in OP patients (p<0.035). In contrast, a positive correlation between t-Hcy and TPx in OP patients was demonstrated significantly, r=0.52, p<0.029.

CONCLUSIONS

We show that the OP group had reduced TAS, whereas the elevated TPx was different from that in the NOP group. Slightly elevated homocysteinemia may contribute to increasing TPx and reducing TAS in the OP group. However, our results suggest a weak but negative relationship between TAS and BMD. Further investigations are needed to examine the relationship of oxidative stress as an endogenous bioactive agent to bone loss in post-menopausal women. Since oxidative stress is the imbalance between total oxidants and antioxidants in the body, any single oxidant/ antioxidant parameter may not reflect overall oxidative stress. Further studies are needed to understand the underlying mechanisms of these findings.

Stimulation of osteogenic differentiation and inhibition of adipogenic differentiation in bone marrow stromal cells by alendronate via ERK and JNK activation

To elucidate the mechanism of the effect of bisphosphonates on bone metabolism, we investigated the effect of alendronate, a widely used bisphosphonate, on osteogenic and adipogenic differentiation in bone marrow stromal cells (BMSCs) derived from ovariectomized SD rats. Alendronate treatment not only increased the mRNA level of bone morphogenetic protein-2, runt-related transcription factor 2, osteopontin, bone sialoprotein, and alkaline phosphatase activity after osteogenic induction, but also decreased the mRNA level of peroxisome proliferator activated receptor gamma 2 and total droplet number indicated by Oil Red O staining after adipogenic induction. The effect of alendronate treatment was dose-dependent, and the difference of the osteogenic or the adipogenic potential between the treated group and the non-treated group was statistically significant (p<0.001). The MAPK-specific inhibitors, PD98059 and SP600125, but not the p38-specific inhibitor, blocked the alendronate-induced regulation of BMSC differentiation. Analysis of BMSCs induced in the presence of alendronate revealed an immediate increase in ERK and JNK phosphorylation. Taken together, these data suggest that alendronate acts on BMSCs to stimulate osteogenic differentiation and inhibit adipogenic differentiation in a dose-dependent manner; this effect is mediated via activating ERK and JNK.