The clinical effectiveness and cost-effectiveness of strontium ranelate for the prevention of osteoporotic fragility fractures in postmenopausal women

Antimicrobial Potential of Strontium-Functionalized Titanium Against Bacteria Associated With Peri-Implantitis

OBJECTIVES

To explore the antimicrobial potential of strontium (Sr)-functionalized wafers against multiple bacteria associated with per-implant infections, in both mono- and multispecies biofilms.

MATERIALS AND METHODS

The bactericidal and bacteriostatic effect of silicon wafers functionalized with a strontium titanium oxygen coating (Sr-Ti-O) or covered only with Ti (controls) against several bacteria, either grown as a mono-species or multispecies biofilms, was assessed using a bacterial viability assay and a plate counting method. Mono-species biofilms were assessed after 2 and 24 h, while the antimicrobial effect on multispecies biofilms was assessed at Days 1, 3, and 6. The impact of Sr functionalization on the total percentage of Porphyromonas gingivalis in the multispecies biofilm, using qPCR, and gingipain activity was also assessed.

RESULTS

Sr-functionalized wafers, compared to controls, were associated with statistically significant less viable cells in both mono- and multispecies tests. The number of colony forming units (CFUs) within the biofilm was significantly less in Sr-functionalized wafers, compared to control wafers, for Staphylococcus aureus at all time points of evaluation and for Escherichia coli at Day 1. Gingipain activity was less in Sr-functionalized wafers, compared to control wafers, and the qPCR showed that P. gingivalis remained below detection levels at Sr-functionalized wafers, while it consisted of 15% of the total biofilm on control wafers at Day 6.

CONCLUSION

Sr functionalization displayed promising antimicrobial potential, possessing bactericidal and bacteriostatic ability against bacteria associated with peri-implantitis grown either as mono-species or mixed in a multispecies consortium with several common oral microorganisms.

Assessing the osseointegration potential of a strontium releasing nanostructured titanium oxide surface: A biomechanical study in the rabbit tibia plateau model

OBJECTIVES

To investigate the impact of a Ti-Sr-O technology, applied to either a turned surface or an SLA surface, on the mechanical robustness of osseointegration, benchmarked against the SLActive surface.

MATERIAL AND METHODS

Ti discs (6.25-mm-diameter and 2-mm-thick) with three different surfaces were inserted on the proximal-anterior part of the tibial plateau of adult Swedish loop rabbits: (I) turned surface modified with Ti-Sr-O (turned + Ti-Sr-O), (II) SLA surface modified with Ti-Sr-O (SLA + Ti-Sr-O), and (III) SLActive surface (SLActive). Following a healing period of 2 weeks and 4 weeks, the pull-out (PO) force needed to detach the discs from the bone was assessed, as a surrogate of osseointegration.

RESULTS

The SLActive surface exhibited statistically significant higher median PO forces, compared with the SLA + Ti-Sr-O surfaces at both 2- and 4 weeks post-op (p > .05). In this study, no single turned + Ti-Sr-O surface disk was integrated.

CONCLUSIONS

The tested Ti-Sr-O technology failed to enhance osseointegration; however, this finding may be related to the inappropriateness of the rabbit tibia plateau model for assessing third-generation implant surface technologies, due to the limited diffusion and clearance at the disk-bone interface.

Absence of medication-related jaw osteonecrosis after treatment with strontium ranelate in ovariectomized rats

This study aimed to evaluate the potential of strontium ranelate (SR) in medication-related jaw osteonecrosis (MRONJ) after tooth extraction in ovariectomized rats. Thirty ovariectomized rats were divided into three groups (n = 10): bisphophonate (BP) group (zoledronic acid; 0.4 mg/kg/week), SR group (625 mg/kg/day), and control group (saline solution). The lower first molars were extracted after 60 days of drug therapy. Drug administration was continued for another 30 days after tooth extraction. The mandibles were subjected to clinical, histological, radiographic, and microtomographic evaluations. Only the BP group showed clinical changes, characterized by the presence of 70% (n = 7) and 20% (n = 2) of ulcers and extraoral fistulas. Radiographic evaluation demonstrated bone sequestration only in the BP group (n = 7, 70%). Microtomographic analysis revealed increased bone porosity after ovariectomy, particularly in the the control group (p < 0.05). The BP group showed a higher bone surface density, bone volume, and trabecular number than SR and control groups, but with less trabecular separation (p < 0.05). All the animals in the BP group demonstrated histological osteonecrosis. There was no evidence of osteonecrosis in the control and SR groups, which was characterized by the absence of empty osteocyte gaps and associated with the gradual healing of the extraction area. Also, an increased number of blood vessels and a reduced number of osteoclasts were observed in the SR group (p < 0.05). Therefore, SR treatment increased angiogenesis and osteoclastogenesis in the healing socket and was not associated with MRONJ development after tooth extraction in ovariectomized rats.

Antimicrobial Properties of Strontium Functionalized Titanium Surfaces for Oral Applications, A Systematic Review

The aim of this systematic review was to assess the current scientific evidence of the antimicrobial potential of strontium (Sr) when used to functionalize titanium (Ti) for oral applications. Out of an initial list of 1081 potentially relevant publications identified in three electronic databases (MEDLINE via PubMed, Scopus, and Cochrane) up to 1 February 2021, nine publications based on in vitro studies met the inclusion criteria. The antimicrobial potential of Sr was investigated on different types of functionalized Ti substrates, employing different application methods. Nine studies reported on the early, i.e., 6–24 h, and two studies on the late, i.e., 7–28 days, antimicrobial effect of Sr, primarily against Staphylococcus aureus (S. aureus) and/or Escherichia coli (E. coli). Sr-modified samples demonstrated relevant early antimicrobial potential against S. aureus in three studies; only one of which presented statistical significance values, while the other two presented only the percentage of antimicrobial rate and biofilm inhibition. A relevant late biofilm inhibition potential against S. aureus of 40% and 10%—after 7 and 14 days, respectively—was reported in one study. Combining Sr with other metal ions, i.e., silver (Ag), zinc (Zn), and fluorine (F), demonstrated a significant antimicrobial effect and biofilm inhibition against both S. aureus and E. coli. Sr ion release within the first 24 h was generally low, i.e., below 50 µg/L and 0.6 ppm; however, sustained Sr ion release for up to 30 days, while maintaining up to 90% of its original content, was also demonstrated. Thus, in most studies included herein, Sr-functionalized Ti showed a limited immediate (i.e., 24 h) antimicrobial effect, likely due to a low Sr ion release; however, with an adequate Sr ion release, a relevant antimicrobial effect, as well as a biofilm inhibition potential against S. aureus—but not E. coli—was observed at both early and late timepoints. Future studies should assess the antimicrobial potential of Ti functionalized with Sr against multispecies biofilms associated with peri-implantitis.

Therapeutic Effect of Strontium Ranelate on Bone in Chemotherapy-Induced Osteopenic Rats via Increased Bone Volume and Reduced Bone Loss

The purpose of this study was to determine whether treatment with strontium ranelate (SrR) can restore bone mass and strength at a skeletal site with established osteopenia in chemotherapy-induced rats. Forty-five Sprague-Dawley male rats were randomly assigned to three study groups (n = 15 rats per group): normal rats (control group), osteopenic rats (chemo group), and osteopenic rats with SrR (chemo-SrR group). We chose a male rat model that mimicked a clinical setting by weekly intravenous injection of cyclophosphamide at 20 mg/kg. The control and chemo groups were maintained without treatment, and the chemo-SrR group was intragastrically administered strontium ranelate at a dosage of 900 mg/kg/day. All animals were fed a standard laboratory diet, and blood samples were collected for biochemical analysis. After 12 weeks of treatment, micro-CT, biomechanical testing, and histomorphometry were examined. In addition, bone samples were obtained to evaluate the content of mineral substances in bones. SrR treatment of chemo rats significantly increased tibial trabecular bone volume, trabecular thickness, and BV/TV. Serum levels of the bone formation marker alkaline phosphatase (ALP) in the SrR group were significantly higher than those in the chemo animals, which was accompanied by an increase in the bone mineral content, bone calcium and phosphate, as well as reduced serum Ca and P concentrations. The serum level of tartrate-resistant acid phosphatase (TRAP) in the SrR treatment group showed no obvious changes. Histomorphological analyses revealed that chemotherapy resulted in decreased osteoclast number, which may be due to the inhibition of bone turnover. However, SrR treatment enhanced the number of osteoblasts while restoring bone mass and improving bone strength in chemo rats. Therefore, the results of this study indicate that SrR treatment has a positive effect on bone in chemotherapy-induced osteoporosis.

Hair for a long-term biological indicator tissue for assessing the strontium nutritional status of men and women

Strontium (Sr) is a trace element that closely resembles calcium metabolism. At the present time there is no available long-term biological indicator tissue for assessing the human Sr nutritional status. Here we have presented a novel concept on how to assess the Sr nutritional status by studying the frequency distribution properties of hair Sr (^SrH) concentration. In this prospective, observational, cross-sectional, and exploratory epidemiological study, we analyzed ^SrH in 311 apparently healthy adult Croatians (123 men, 188 women). Hair strontium was analyzed by the ICP-MS. The natural frequency distribution of ^SrH followed the Power law, so that the data were analyzed by fitting the logistic bioassay sigmoid curve (ogive) of median derivatives. Women tend to accumulate three and a half time more ^SrH than men (median men 867ngg^-1 vs. median women 3120ngg^-1). The normal (adequate) linear physiological response range of the sigmoid curve was 351-3489ngg^-1 for men and 846-8457ngg^-1 for women. Values below that linear range are considered to indicate deficient Sr nutritional status, whereas values above that linear range indicate excessive strontium exposure. Hair, as a long-term, and whole blood as a short-term biological indicator tissues were not commensurable entities. Similarly, ^SrH accumulation was not age dependent in either men or women. Hair strontium is a reliable long-term biological indicator tissue for assessing the strontium nutritional status.

Strontium ranelate causes osteophytes overgrowth in a model of early phase osteoarthritis

Background

Osteoarthritis (OA) involves cartilage changes as well as modifications of subchondral bone and synovial tissues. Strontium ranelate (SR), an anti-osteoporosis compound, which is currently in phase III clinical trial for treatment of OA. Evidences suggest that SR preferably deposited in osteophyte, other than in subchondral bone in early phase of OA. This phenomenon raises concern about its utility for OA treatment as a disease-modifying drug. To evaluate the effect of SR on cartilage, subchondral bone mass and subchondral trabecular bone structure in medial meniscectomized (MNX) guinea pigs.

Method

Thirty-six 3-month-old male Dunkin Hartley albino guinea pigs received either sham or medial meniscectomy operations. One week after the procedure, meniscectomized animals began 12 weeks of SR (625 mg/kg, daily) treatment by oral gavage for MNX + SR group, or normal saline for MNX + V group. All animals were euthanized 12 weeks later, cartilage degeneration and subchondral bone micro-architecture was analyzed.

Results

Both OARSI scores (P = 0.523 for marcoscopic scores, P = 0.297 for histological scores) and Cartilage thickness (P = 0.335) in MNX + SR group were comparable to MNX + V group. However, osteophyte sizes were larger in MNX + SR group (P = 0.014), and collapsed osteophytes in MNX + SR group (7 by 12) were significantly more than in MNX + V group (1 by 12) (P = 0.027), while immunohistochemistry indicates catabolic changes in osteophyte/plateau junction. Micro-CT analysis showed bone mineral density (BMD) (P = 0.001), bone volume fraction (BV/TV) (P = 0.008), trabecular spacing (Tb.Sp) (P = 0.020), trabecular thickness (Tb.Th) (P = 0.012) and structure model index (SMI) (P = 0.005) levels to be significantly higher in the MNX + SR group than in the MNX + V group.

Conclusions

SR (625 mg/kg/day) did not protect cartilage from degeneration in MNX guinea pigs but subchondral bone was significantly enhanced. In early phase OA, SR administration causes osteophyte overgrowth, which may be related to incorporation into mineralizing osteophytes. This adverse effect is important for future studies of SR in OA.

A model for measuring the health burden of classic congenital adrenal hyperplasia in adults

AIM

Patients with classic congenital adrenal hyperplasia (CAH) have poor health outcomes. In the absence of a comprehensive observational study, this manuscript provides a model to estimate the lifetime disease burden of adults with classic CAH.

METHODS

The model, built in Excel, comprises subdomains addressing the health consequences of CAH and synthesises evidence from clinical and epidemiological studies on health outcomes.

RESULTS

The model estimates that adults with classic CAH will implement 'sick day rules' (doubling or tripling glucocorticoid and/or use of parenteral therapy) 171 times over their lifetime and attend hospital for adrenal crisis on 11 occasions. In a population of 1000, over 200 will die of a condition complicated by adrenal crisis resulting, on average, in a loss of 7 years of life. Patients with CAH may also suffer from excess CVD events. Treatment with glucocorticoids almost doubles the risk of bone fractures in patients with CAH compared to the general population, leading on average to an additional 0·8 fractures per patient with CAH over their lifetime.

CONCLUSIONS

The disease burden model highlights gaps in evidence, particularly regarding intensity of care and adrenal crisis, and the relationship between control of CAH and risks of CVD, osteoporosis, diabetes and infertility. The model can be used for research on the impact of new clinical pathways and therapeutic interventions in terms of clinical events and cost.

Osteoporosis in East Asia: Current issues in assessment and management

The greatest burden of hip fractures around the world is expected to occur in East Asia, especially China. However, there is a relative paucity of information on the epidemiology and burden of fractures in East Asia. Osteoporosis is greatly under-diagnosed and under-treated, even among the highest-risk subjects who have already suffered fractures. The accessibility to bone densitometry, the awareness of the disease by professionals and the public, and the use and reimbursement of drugs are some of the areas which need improvement especially. Cost-effective analysis on screening strategy and intervention thresholds based on local epidemiology data and economic status are available only in Japan. In addition, clinical risk factor models for the assessment of fracture probability may be ethnic specific. Further research is needed to develop a cost-effective risk assessment strategy to identify high-risk individuals for screening and treatment based on local data. Moreover, inadequate calcium and vitamin D intake is still an issue faced by this region.

History of cardiovascular events and cardiovascular risk factors among patients initiating strontium ranelate for treatment of osteoporosis

PURPOSE

To estimate the proportion of osteoporosis patients in whom initiating strontium ranelate treatment, under new EMA guidelines, should be contraindicated because of a history of cardiovascular events or risk for cardiovascular events.

MATERIALS AND METHODS

This was a retrospective analysis of medical and pharmacy claims using the Clinical Practice Research Datalink database. Patients were included if they had ≥1 prescription of strontium from September 1, 2008 to August 31, 2013, were aged ≥50 as of the index date (the date of the first ever strontium ranelate prescription), and had ≥1 year of medical records pre-index. Cardiovascular events occurring any time pre-index were identified, which included ischemic heart disease, cerebrovascular disease, uncontrolled hypertension, and peripheral arterial disease. Cardiovascular risk factors assessed included 1) diabetes or hypertension any time pre-index; 2) hyperlipidemia in the 12 months pre-index; or 3) obesity in the 12 months pre-index.

RESULTS

A total of 7,474 patients were included: 90.4% were women, with an average age of 76.5 years, and 84.5% used osteoporosis therapy, either bisphosphonates or non-bisphosphonates, prior to strontium initiation. A total of 23.6% of patients experienced ≥1 cardiovascular event prior to strontium initiation; the rate was lower among female patients than in male patients (22.4% vs 35.3%, P<0.01). A total of 45.9% had risk factors for cardiovascular events (without cardiovascular event history).

CONCLUSION

More than one-fifth of osteoporosis patients in the UK who used strontium had a cardiovascular event history, and one-half had cardiovascular risk factors prior to strontium initiation.

Predictors of re-fracture amongst patients managed within a secondary fracture prevention program: a 7-year prospective study

SUMMARY

This 7-year prospective observational study determined the predictors of re-fracture amongst 234 patients managed within a Secondary Fracture Prevention programme. Poor compliance, multiple co-morbidities, corticosteroid therapy, low hip bone mineral density (BMD) or low body weight were all significantly associated with re-fracture in patients commenced on long-term anti-resorptive therapy.

INTRODUCTION

Risk factors for osteoporotic fracture amongst treatment-naïve patients are well established. In contrast, predictors of re-fracture in patients optimally managed within a Secondary Fracture Prevention (SFP) programme are ill-defined.

METHODS

This prospective observational study included 234 subjects with incident osteoporotic fractures managed long-term by the Concord SFP programme. Using Cox proportional hazards models, predictors of re-fracture were analysed separately for patients commenced on specific pharmacotherapy (group 1, N=171) and subjects receiving calcium and/or vitamin D supplements only (group 2, N=63). Relevant anthropometric, clinical and technical data were documented at each visit. Compliance and persistence were analysed as time-varying covariates.

RESULTS

During a mean follow-up of 5.2 (range 3.5-7.3) years, 20.9% of all subjects re-fractured (26.3% in group 1, 6.3% in group 2). Multivariate predictors of re-fracture in group 1 were significant co-morbidity (HR 2.04 if >3, 95% CI 1.10-3.79, p=0.024), corticosteroid use (HR 1.75, 95% CI 1.12-2.73, p=0.013) and total hip BMD (HR 1.36 per 0.1 g/cm2 decrease, 95% CI 1.08-1.70, p=0.008). In contrast, gender, prevalent fractures and lumbar spine BMD were not associated with re-fracture. Amongst patients with complete compliance data, a medication possession ratio of ≤50% (HR 3.36, 95% CI 1.32-8.53, p=0.011) and low body weight (HR 1.04 per 1-kg decrease, 95% CI 1.003-1.08, p=0.032) were significantly associated with re-fracture.

CONCLUSIONS

Amongst patients managed within a dedicated SFP programme, poor compliance, multiple co-morbidities, corticosteroid therapy, low hip BMD or low body weight are all associated with increased risk of re-fracture. This subgroup of patients therefore require intensive management including strategies to improve compliance.

Indirect comparison of bazedoxifene vs oral bisphosphonates for the prevention of vertebral fractures in postmenopausal osteoporotic women

OBJECTIVE

Compare the efficacy of bazedoxifene with oral bisphosphonates for reduction of vertebral fracture risk in postmenopausal osteoporotic (PMO) women and in higher-risk patients based on evidence from randomized controlled trials (RCTs).

METHODS

Eight RCTs assessing vertebral fracture risk reduction with oral bisphosphonates (n = 7) or bazedoxifene (n = 1) were identified by a systematic literature review. Individual study results were pooled in a network meta-analysis (NMA) to indirectly compare treatment effects for overall PMO women and a higher-risk subgroup (FRAX ≥ 20%). Three sets of NMA analyses were conducted: aggregate data (AD) from the bisphosphonate RCTs and bazedoxifene RCT for the full population or the FRAX ≥20% subgroup (NMA AD); bisphosphonate AD and bazedoxifene AD from each FRAX subgroup adjusted for baseline risk (NMA AD meta-regression); and bisphosphonate AD and bazedoxifene individual patient data (IPD) adjusted for baseline risk/FRAX (NMA AD/IPD meta-regression).

RESULTS

For the overall population, bisphosphonates had lower fracture risks versus bazedoxifene although there is considerable uncertainty in supporting one intervention over another. The relative risk reduction (RRR) for bazedoxifene was -0.23 (95% CrI: -1.11, 0.27) versus ibandronate, -0.17 (-0.76, 0.22) versus alendronate, and -0.06 (-0.62, 0.30) versus risedronate. RESULTS from the meta-regression analyses were similar. For the FRAX ≥20% population, estimated fracture rates with bazedoxifene were lower than with bisphosphonates, but again the uncertainty limits strong interpretation. The RRR for bazedoxifene was 0.51 (-0.31, 0.83) versus ibandronate, 0.53 (-0.18, 0.83) versus alendronate, and 0.57 (-0.07, 0.85) versus risedronate. The meta-regression analyses showed comparable findings.

CONCLUSION

The analyses only considered vertebral fractures for oral bisphosphonates versus bazedoxifene, and IPD was available only for bazedoxifene. In light of this, bazedoxifene is comparable to bisphosphonates in the overall PMO population and at least as effective as bisphosphonates for preventing vertebral fractures among higher-risk PMO patients. The findings suggest bazedoxifene performs better in higher-risk PMO than in the overall PMO.

Modelling the cost effectiveness of interventions for osteoporosis: issues to consider

Expenditure on treating osteoporotic fractures and on preventative intervention is considerable and is likely to rise in forthcoming years due to the association between fracture risk and age. With funders such as the National Institute for Health and Care Excellence and the Pharmaceutical Benefits Advisory Committee explicitly considering cost-effectiveness analyses within the process of producing guidance, it is imperative that economic models are as robust as possible. This article details issues that need to be considered specifically related to health technology assessments of interventions for osteoporosis, and highlights limitations within the current evidence base. A likely direction of impact on cost effectiveness of addressing the key issues has been included alongside a tentative categorization of the level of these impacts. It is likely that cost-effectiveness ratios presented in previous models that did not address the identified issues were favourable to interventions.

Bazedoxifene versus oral bisphosphonates for the prevention of nonvertebral fractures in postmenopausal women with osteoporosis at higher risk of fracture: a network meta-analysis

OBJECTIVE

To compare the efficacy of bazedoxifene and oral bisphosphonates for the prevention of nonvertebral fractures (NVFs) in women with higher risk of postmenopausal osteoporosis (i.e., the Fracture Risk Assessment Tool [FRAX] score ≥ 20%), based on currently available evidence from randomized controlled trials.

METHODS

Randomized controlled trials evaluating the NVF relative risk reduction (RRR) with oral bisphosphonates or bazedoxifene were identified by a systematic literature review and combined by means of a network meta-analysis. A subgroup of patients with a FRAX score of 20% or more in the bazedoxifene phase III osteoporosis study was selected as the population of interest on the basis of the bazedoxifene label. In one analysis (analysis 1), the placebo response of the subgroup with a FRAX score of 20% or more was the benchmark to select comparable bisphosphonate trials. Additional analyses incorporated the aggregate data from the bisphosphonate trials with all the FRAX subgroups (analysis 2) or with the individual patient data from the bazedoxifene trial (analysis 3).

RESULTS

Nine identified bisphosphonate trials (alendronate, ibandronate, risedronate; N = 23,440 patients) with a similar placebo response as observed for the subgroup of high risk patients in the bazedoxifene trial were included in analysis 1. The results of the network meta-analysis of this study set suggest that bazedoxifene is expected to have an RRR of 0.43 (95% credible interval [CrI] -0.19 to 0.72) versus alendronate, 0.58 (95% CrI 0.05-0.81) versus ibandronate, and 0.39 (95% CrI -0.29 to 0.70) versus risedronate. Analyses in which treatment effects with bisphosphonates were projected to a population with a FRAX score of 20% or more with meta-regression approaches (analysis 2 and analysis 3) provide similar findings.

CONCLUSION

Based on an indirect comparison of randomized trials, bazedoxifene is expected to have at least a comparable RRR of NVF as alendronate, ibandronate, and risedronate in women with higher risk of postmenopausal osteoporosis.

A systematic review of models used in cost-effectiveness analyses of preventing osteoporotic fractures

This review was aimed at the evolution of health economic models used in evaluations of clinical approaches aimed at preventing osteoporotic fractures. Models have improved, with medical continuance becoming increasingly recognized as a contributor to health and economic outcomes, as well as advancements in epidemiological data. Model-based health economic evaluation studies are increasingly used to investigate the cost-effectiveness of osteoporotic fracture preventions and treatments. The objective of this study was to carry out a systematic review of the evolution of health economic models used in the evaluation of osteoporotic fracture preventions. Electronic searches within MEDLINE and EMBASE were carried out using a predefined search strategy. Inclusion and exclusion criteria were used to select relevant studies. References listed of included studies were searched to identify any potential study that was not captured in our electronic search. Data on country, interventions, type of fracture prevention, evaluation perspective, type of model, time horizon, fracture sites, expressed costs, types of costs included, and effectiveness measurement were extracted. Seventy-four models were described in 104 publications, of which 69% were European. Earlier models focused mainly on hip, vertebral, and wrist fracture, but later models included multiple fracture sites (humerus, pelvis, tibia, and other fractures). Modeling techniques have evolved from simple decision trees, through deterministic Markov processes to individual patient simulation models accounting for uncertainty in multiple parameters. Treatment continuance has been increasingly taken into account in the models in the last decade. Models have evolved in their complexity and emphasis, with medical continuance becoming increasingly recognized as a contributor to health and economic outcomes. This evolution may be driven in part by the desire to capture all the important differentiating characteristics of medications under scrutiny, as well as the advancement in epidemiological data relevant to osteoporosis fractures.

Cost-utility analysis of duloxetine in osteoarthritis: a US private payer perspective

BACKGROUND

Duloxetine has recently been approved in the USA for chronic musculoskeletal pain, including osteoarthritis and chronic low back pain. The cost effectiveness of duloxetine in osteoarthritis has not previously been assessed. Duloxetine is targeted as post first-line (after acetaminophen) treatment of moderate to severe pain.

OBJECTIVE

The objective of this study was to estimate the cost effectiveness of duloxetine in the treatment of osteoarthritis from a US private payer perspective compared with other post first-line oral treatments, including nonsteroidal anti-inflammatory drugs (NSAIDs), and both strong and weak opioids.

METHODS

A cost-utility analysis was performed using a discrete-state, time-dependent semi-Markov model based on the National Institute for Health and Clinical Excellence (NICE) model documented in its 2008 osteoarthritis guidelines. The model was extended for opioids by adding titration, discontinuation and additional adverse events (AEs). A life-long time horizon was adopted to capture the full consequences of NSAID-induced AEs. Fourteen health states comprised the structure of the model: treatment without persistent AE, six during-AE states, six post-AE states and death. Treatment-specific utilities were calculated using the transfer-to-utility method and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total scores from a meta-analysis of osteoarthritis clinical trials of 12 weeks and longer. Costs for 2011 were estimated using Red Book, The Agency for Healthcare Research and Quality's Healthcare Cost and Utilization Project database, the literature and, sparingly, expert opinion. One-way and probabilistic sensitivity analyses were undertaken, as well as subgroup analyses of patients over 65 years old and a population at greater risk of NSAID-related AEs.

RESULTS

In the base case the model estimated naproxen to be the lowest total-cost treatment, tapentadol the highest cost, and duloxetine the most effective after considering AEs. Duloxetine accumulated 0.027 discounted quality-adjusted life-years (QALYs) more than naproxen and 0.013 more than oxycodone. Celecoxib was dominated by naproxen, tramadol was subject to extended dominance, and strong opioids were dominated by duloxetine. The model estimated an incremental cost-effectiveness ratio (ICER) of US$47,678 per QALY for duloxetine versus naproxen. One-way sensitivity analysis identified the probabilities of NSAID-related cardiovascular AEs as the inputs to which the ICER was most sensitive when duloxetine was compared with an NSAID. When compared with a strong opioid, duloxetine dominated the opioid under nearly all sensitivity analysis scenarios. When compared with tramadol, the ICER was most sensitive to the costs of duloxetine and tramadol. In subgroup analysis, the cost per QALY for duloxetine versus naproxen fell to US$24,125 for patients over 65 years and to US$18,472 for a population at high risk of cardiovascular and gastrointestinal AEs.

CONCLUSION

The model estimated that duloxetine was potentially cost effective in the base-case population and more cost effective for subgroups over 65 years or at high risk of NSAID-related AEs. In sensitivity analysis, duloxetine dominated all strong opioids in nearly all scenarios.

Cost-effectiveness of duloxetine in chronic low back pain: a Quebec societal perspective

STUDY DESIGN

Cost-effectiveness model from a Quebec societal perspective using meta-analyses of clinical trials.

OBJECTIVE

To evaluate the cost-effectiveness of duloxetine in chronic low back pain (CLBP) compared with other post-first-line oral medications.

SUMMARY OF BACKGROUND DATA

Duloxetine has recently received a CLBP indication in Canada. The cost-effectiveness of duloxetine and other oral medications has not previously been evaluated for CLBP.

METHODS

A Markov model was created on the basis of the economic model documented in the 2008 osteoarthritis clinical guidelines of the National Institute for Health and Clinical Excellence. Treatment-specific utilities were estimated via a meta-analysis of CLBP clinical trials and a transfer-to-utility regression estimated from duloxetine CLBP trial data. Adverse event rates of comparator treatments were taken from the National Institute for Health and Clinical Excellence model or estimated by a meta-analysis of clinical trials in osteoarthritis using a maximum-likelihood simulation technique. Costs were developed primarily from Quebec and Ontario public sources as well as the published literature and expert opinion. The 6 comparators were celecoxib, naproxen, amitriptyline, pregabalin, hydromorphone, and oxycodone. Subgroup analyses and 1-way and probabilistic sensitivity analyses were performed.

RESULTS

In the base case, naproxen, celecoxib, and duloxetine were on the cost-effectiveness frontier, with naproxen the least expensive medication, celecoxib with an incremental cost-effectiveness ratio of $19,881, and duloxetine with an incremental cost-effectiveness ratio of $43,437. Other comparators were dominated. Key drivers included the rates of cardiovascular and gastrointestinal adverse events and proton pump inhibitor usage. In subgroup analysis, the incremental cost-effectiveness ratio for duloxetine fell to $21,567 for a population 65 years or older and to $18,726 for a population at higher risk of cardiovascular and gastrointestinal adverse events.

CONCLUSION

The model estimates that duloxetine is a moderately cost-effective treatment for CLBP, becoming more cost-effective for populations older than 65 years or at greater risk of cardiovascular and gastrointestinal events.

LEVEL OF EVIDENCE

1.

Health care costs of osteopenia, osteoporosis, and fragility fractures in Mexico

Different sources were used to estimate the 2010 health care costs of managing low bone density (osteopenia/osteoporosis) plus caring fragility fractures in Mexico at 411 million USD. Figures are projected to rise 42 % by 2020. Preventive and timely interventions are required to decrease the financial burden of these entities.

INTRODUCTION

Osteopenia, osteoporosis, and fragility fractures (FF) are a public health concern. The study purpose was to estimate the health care costs of these conditions in Mexico during 2010 and project them to 2015 and 2020.

METHODS

Prevalence of osteopenia and osteoporosis was derived from international data. The Mexican version of FRAX® algorithm was used to assess risk for a major FF (hip, clinical spine, forearm, and proximal humerus) in osteopenic and osteoporotic population aged over 40 years. The estimates were applied to national demographic projections. Only direct medical costs composed by routine non-pharmacological management of osteopenia/osteoporosis besides the costs owing to medical care of major FF were considered into the analysis. Resource use for managing osteopenia/osteoporosis was defined from local sources (clinical practice guidelines, published literature, and expert opinion); unit costs were gathered from official lists. Costs for medical care of FF were based on diagnosis-related groups.

RESULTS

In population aged ≥40 years, prevalence of osteopenia and osteoporosis in 2010 was 32.8 and 8 %, respectively. A total of 75,763 FF occurred that year. Costs of managing osteopenia and osteoporosis were 154.9 million USD, whereas medical costs due to FF reached 256.2 million USD. Therefore, the annual health care costs of these entities in 2010 were 411 million USD. Total costs will be 19.2 % higher in 2015, and by 2020, the figures will have increased by 41.7 %.

CONCLUSIONS

Low bone density entails substantial epidemiological and financial burden in Mexico, and their impact will grow considerably during the next years.

The cost-effectiveness of duloxetine in chronic low back pain: a US private payer perspective

OBJECTIVE

To assess the cost-effectiveness of duloxetine in the treatment of chronic low back pain (CLBP) from a US private payer perspective.

METHODS

A cost-utility analysis was undertaken for duloxetine and seven oral post-first-line comparators, including nonsteroidal anti-inflammatory drugs (NSAIDs), weak and strong opioids, and an anticonvulsant. We created a Markov model on the basis of the National Institute for Health and Clinical Excellence model documented in its 2008 osteoarthritis clinical guidelines. Health states included treatment, death, and 12 states associated with serious adverse events (AEs). We estimated treatment-specific utilities by carrying out a meta-analysis of pain scores from CLBP clinical trials and developing a transfer-to-utility equation using duloxetine CLBP patient-level data. Probabilities of AEs were taken from the National Institute for Health and Clinical Excellence model or estimated from osteoarthritis clinical trials by using a novel maximum-likelihood simulation technique. Costs were gathered from Red Book, Agency for Healthcare Research and Quality's Healthcare Cost and Utilization Project database, the literature, and, for a limited number of inputs, expert opinion. The model performed one-way and probabilistic sensitivity analyses and generated incremental cost-effectiveness ratios (ICERs) and cost acceptability curves.

RESULTS

The model estimated an ICER of $59,473 for duloxetine over naproxen. ICERs under $30,000 were estimated for duloxetine over non-NSAIDs, with duloxetine dominating all strong opioids. In subpopulations at a higher risk of NSAID-related AEs, the ICER over naproxen was $33,105 or lower.

CONCLUSIONS

Duloxetine appears to be a cost-effective post-first-line treatment for CLBP compared with all but generic NSAIDs. In subpopulations at risk of NSAID-related AEs, it is particularly cost-effective.

Models of care for the secondary prevention of osteoporotic fractures: a systematic review and meta-analysis

Most people presenting with incident osteoporotic fractures are neither assessed nor treated for osteoporosis to reduce their risk of further fractures, despite the availability of effective treatments. We evaluated the effectiveness of published models of care for the secondary prevention of osteoporotic fractures. We searched eight medical literature databases to identify reports published between 1996 and 2011, describing models of care for secondary fracture prevention. Information extracted from each publication included study design, patient characteristics, identification strategies, assessment and treatment initiation strategies, as well as outcome measures (rates of bone mineral density (BMD) testing, osteoporosis treatment initiation, adherence, re-fractures and cost-effectiveness). Meta-analyses of studies with valid control groups were conducted for two outcome measures: BMD testing and osteoporosis treatment initiation. Out of 574 references, 42 articles were identified as analysable. These studies were grouped into four general models of care-type A: identification, assessment and treatment of patients as part of the service; type B: similar to A, without treatment initiation; type C: alerting patients plus primary care physicians; and type D: patient education only. Meta-regressions revealed a trend towards increased BMD testing (p = 0.06) and treatment initiation (p = 0.03) with increasing intensity of intervention. One type A service with a valid control group showed a significant decrease in re-fractures. Types A and B services were cost-effective, although definition of cost-effectiveness varied between studies. Fully coordinated, intensive models of care for secondary fracture prevention are more effective in improving patient outcomes than approaches involving alerts and/or education only.

European guidance for the diagnosis and management of osteoporosis in postmenopausal women

Guidance is provided in a European setting on the assessment and treatment of postmenopausal women at risk of fractures due to osteoporosis.

INTRODUCTION

The International Osteoporosis Foundation and European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis published guidance for the diagnosis and management of osteoporosis in 2008. This manuscript updates these in a European setting.

METHODS

Systematic literature reviews.

RESULTS

The following areas are reviewed: the role of bone mineral density measurement for the diagnosis of osteoporosis and assessment of fracture risk, general and pharmacological management of osteoporosis, monitoring of treatment, assessment of fracture risk, case finding strategies, investigation of patients and health economics of treatment.

CONCLUSIONS

A platform is provided on which specific guidelines can be developed for national use.

A comparison of case-finding strategies in the UK for the management of hip fractures

Treatment criteria published by the National Osteoporosis Guideline Group (NOGG) in the UK make more efficient use of bone mineral density (BMD) resources than the previous Royal College of Physicians (RCP) guideline.

INTRODUCTION

We compared the effectiveness of the RCP case-finding strategy previously used in the UK and the updated guideline published by NOGG, which incorporates the FRAX® fracture probability tool.

METHODS

Comparisons were made by simulating population samples of 1000 women at ages between 50 and 85 years, using age-specific prevalence of risk factors and UK-derived fracture and mortality rates. Comparators comprised the number identified at high risk, the incidence of hip fracture and the femoral neck BMD in those identified, the number needed to scan to identify a hip fracture, the acquisition cost and the cost per hip fracture averted

RESULTS

Compared with the RCP strategy, NOGG identified slightly reduced numbers of women at high risk (average 34.6% vs. 35.7% across all ages), but with lower numbers of scans required at each age. For example, NOGG required only 3.5 scans at the age of 50 years to identify one case of hip fracture, whereas RCP required 13.9. At 75 years, the corresponding numbers were 0.9 and 1.5. Thus, the acquisition costs for identifying a hip fracture case and the total costs (acquisition and treatment) per hip fracture averted were lower.

CONCLUSION

Compared to the RCP strategy, the FRAX-based NOGG strategy uses BMD resources more efficiently with lower acquisition costs and lower costs per hip fracture averted.

Cost-effectiveness of different strategies for selecting and treating individuals at increased risk of osteoporosis or osteopenia: a systematic review

OBJECTIVES

To compare cost-effectiveness modeling analyses of strategies to prevent osteoporotic and osteopenic fractures either based on fixed thresholds using bone mineral density or based on variable thresholds including bone mineral density and clinical risk factors.

METHODS

A systematic review was performed by using the MEDLINE database and reference lists from previous reviews. On the basis of predefined inclusion/exclusion criteria, we identified relevant studies published since January 2006. Articles included for the review were assessed for their methodological quality and results.

RESULTS

The literature search resulted in 24 analyses, 14 of them using a fixed-threshold approach and 10 using a variable-threshold approach. On average, 70% of the criteria for methodological quality were fulfilled, but almost half of the analyses did not include medication adherence in the base case. The results of variable-threshold strategies were more homogeneous and showed more favorable incremental cost-effectiveness ratios compared with those based on a fixed threshold with bone mineral density. For analyses with fixed thresholds, incremental cost-effectiveness ratios varied from €80,000 per quality-adjusted life-year in women aged 55 years to cost saving in women aged 80 years. For analyses with variable thresholds, the range was €47,000 to cost savings.

CONCLUSIONS

Risk assessment using variable thresholds appears to be more cost-effective than selecting high-risk individuals by fixed thresholds. Although the overall quality of the studies was fairly good, future economic analyses should further improve their methods, particularly in terms of including more fracture types, incorporating medication adherence, and including or discussing unrelated costs during added life-years.

Cost effectiveness of secondary vs tertiary prevention for post-menopausal osteoporosis

BACKGROUND

The aging of the population is likely to increase the number of osteoporosis-related fractures, such as hip fractures, and hence the economic burden for society. Therefore, strategies to identify women at increased risk are of major interest.

OBJECTIVE

The aim of this study was to determine the cost effectiveness of preventive services for osteoporosis, comparing secondary plus tertiary prevention (SP/TP) versus tertiary prevention (TP) alone in post-menopausal women in Germany.

METHODS

A cost-utility analysis and a budget-impact analysis were performed from the perspective of the German statutory health insurance (SHI). A Markov model simulated costs and benefits discounted at 3% over a lifetime horizon.

RESULTS

Cost effectiveness of TP compared with no screening was 669 Euros, 477 Euros and 385 Euros per QALY for women aged 60, 70 and 80 years, respectively (year 2010 values). In women aged 50 years, TP dominated no prevention. Cost effectiveness of SP/TP compared with TP was 4543 Euros, 19791 Euros, 8670 Euros and 3368 Euros for women aged 50, 60, 70 and 80 years, respectively. SP/TP resulted in additional costs of 109 million Euros or 0.10% of the SHI's annual budget (TP alone = 8 million Euros).

CONCLUSION

Compared with TP, a strategy based on SP/TP appears to be more expensive but more effective in each age group. Given that cost effectiveness seems acceptable, allocation of resources to SP/TP to decrease post-menopausal osteoporotic fracture risk may be justified.

The cost effectiveness of zoledronic acid 5 mg for the management of postmenopausal osteoporosis in women with prior fractures: evidence from Finland, Norway and the Netherlands

OBJECTIVE

This study was conducted to assess the cost effectiveness of zoledronic acid 5 mg as a first-line treatment for the secondary prevention of fragility fractures in women with postmenopausal osteoporosis in Finland, Norway and the Netherlands.

METHODS

A discrete-event, individual-patient computer-simulation model was used to compare the cost effectiveness of zoledronic acid with that of basic treatment (calcium and vitamin D) and commonly prescribed bisphosphonates in postmenopausal women aged 50-80 years who have experienced one previous fracture and have a bone mineral density T-score of -2.5.

RESULTS

The cost per quality-adjusted life-year (QALY) gained with zoledronic acid compared with basic treatment ranged from being cost saving in all age groups in Norway, to costing approximately €19,000 in Finland and €22,300 in the Netherlands. Compared with the other branded bisphosphonates, zoledronic acid was cost saving in many scenarios, including all age groups in Finland. In Norway, zoledronic acid dominated branded risedronate and ibandronate in all age groups and dominated or had incremental cost-effectiveness ratios (ICERs) of up to NOK83,954 per QALY gained compared with branded alendronate. In the Netherlands, zoledronic acid dominated branded intravenous ibandronate in all age groups; compared with branded risedronate and oral ibandronate, zoledronic acid dominated or had ICERs of up to €4832 per QALY gained; compared with branded alendronate, it had ICERs of up to €48,383 per QALY gained. In all three countries, zoledronic acid may be cost effective compared with generic alendronate when patient compliance with drug therapy is taken into account. Sensitivity analyses showed that the model was robust to changes in key values. The main model limitations were the lack of real-life compliance and persistence data, and lack of country-specific data for some parameters.

CONCLUSIONS

Using local or commonly used thresholds, this analysis suggests that zoledronic acid would be a cost-effective first-line option compared with other branded bisphosphonates and, in some scenarios, compared with generic alendronate, for the secondary prevention of fractures in women with postmenopausal osteoporosis in Finland, Norway and the Netherlands.

FRAX and its applications in health economics--cost-effectiveness and intervention thresholds using bazedoxifene in a Swedish setting as an example

BACKGROUND

An important aspect of cost-effectiveness analysis of osteoporosis is to accurately model the fracture risk and mortality related to the patient groups in the analysis. The estimation of fracture risk is based on a number of factors, such as the level of general risk of the normal population, the effect of treatment and the prevalence of clinical risk factors (CRFs) for fracture. Fracture risk has traditionally been calculated with risk adjustments based on age, bone mineral density and prior vertebral fracture. The treatment effect has been derived from clinical trials and, in the absence of subgroup analyses, the same efficacy has been assumed irrespective of the fracture risk of the population. The FRAX tool enables the estimation of risk based on a wider range of risk factors, and treatment efficacy that is dependent on the level of risk in the analyzed population. The objective was to describe the implementation of the FRAX algorithms into health economic osteoporosis models and to highlight how it differs from traditional risk assessment.

METHODS

The selective estrogen receptor modulator, bazedoxifene, was evaluated in a Swedish setting with traditional and FRAX-based risk assessment in a previously developed Markov model that included fractures and thromboembolic events, and also was adapted to accommodate risk-dependent efficacy, which is available for bazedoxifene.

RESULTS

The traditional approach gave lower ICERs at ages up to 60 years compared to the FRAX method when only considering age, BMD and prior fracture. At 70 years and older and when adding more CRFs with the FRAX approach, the FRAX ICER decreased and fell below the traditional approach. The risk dependant efficacy was the main reason for lower ICERs with FRAX in women at higher risk of fracture.

DISCUSSION

FRAX applied in cost-effectiveness analyses is a more granular method for the estimation of fracture risk, mortality and efficacy compared to previous approaches that can also improve case finding. Furthermore, it facilitates the estimation of cost-effectiveness for various types of patients with different combinations of CRFs, which more closely matches patients in clinical practice.

The cost effectiveness of a randomized controlled trial to establish the relative efficacy of vitamin K1 compared with alendronate

PURPOSE

The authors aimed to evaluate whether vitamin K(1) or alendronate (the recommended treatment in England and Wales for postmenopausal women with a previous fracture) appeared to be the more cost-effective treatment for fracture prevention. Furthermore, expected value of sample information (EVSI) analyses were undertaken to estimate whether a head-to-head trial of alendronate and vitamin K(1) would be considered cost effective.

METHOD

A published osteoporosis model structure, populated with data from literature reviews, was used to evaluate the costs and quality-adjusted life-years associated with each intervention being provided to women at high risk of fracture, given current information. A lifetime horizon and a national health service and personal social services cost perspective were used. Observed outcomes from head-to-head randomized controlled trials (RCTs) of predetermined sizes were simulated and synthesized with existing data to formulate posterior distributions, which were used to estimate the more cost-effective treatment given these additional data. The EVSI was estimated and the expected net benefit of sampling (ENBS) calculated by subtracting the proposed trial costs.

RESULTS

Given current information, vitamin K(1) is expected to dominate alendronate. However, this was subject to a considerable degree of uncertainty; dominance was reversed when it was assumed that vitamin K(1) had no effect on hip fractures. EVSI analysis indicated that an RCT of 2000 or 5000 women per arm produced high, and comparable, ENBS. These results were maintained in sensitivity analyses.

CONCLUSIONS

It is concluded that an RCT recruiting between 2000 and 5000 women per arm to evaluate the relative efficacy of alendronate and vitamin K(1) appears to be cost effective for informing decision making in England and Wales.

Cost-effectiveness of strontium ranelate versus risedronate in the treatment of postmenopausal osteoporotic women aged over 75 years

OBJECTIVE

To estimate the cost-effectiveness of strontium ranelate in the treatment of postmenopausal osteoporotic women aged over 75 years.

MATERIALS AND METHODS

A validated Markov microsimulation model with a Belgian payer's perspective estimated the cost per quality-adjusted life-year (QALY) of a 3-year strontium ranelate treatment compared with no treatment and with the bisphosphonate risedronate. Data on the effect of both treatments on fracture risk were taken from the Cochrane Database of Systematic Reviews. Analyses were performed for postmenopausal women aged 75 and 80 years, either with a diagnosis of osteoporosis (i.e. bone mineral density T-score <or=-2.5 SD) or with prevalent vertebral fractures (PVF). Parameter uncertainty was evaluated using both one-way and probabilistic sensitivity analyses.

RESULTS

Strontium ranelate was dominant (i.e. more effective and less costly) versus risedronate for women with osteoporosis aged over 75 years and for women with PVF aged 80 years. The cost per QALY gained of strontium ranelate compared with risedronate at 75 years of age was euro 11,435 for women with PVF. When compared with no treatment, the costs per QALY gained of strontium ranelate were euro 15,588 and euro 7,708 at 75 and 80 years of age for women with osteoporosis; the equivalent values were euro 16,518 and euro 6,015 for women with PVF. Probabilistic sensitivity analyses showed that strontium ranelate was generally more cost-effective than risedronate, in the range of 60% in all cases.

CONCLUSION

The results of this study suggest that strontium ranelate is a cost-effective strategy, in a Belgian setting, for the treatment of postmenopausal osteoporotic women aged over 75 years.

Cost-effectiveness of using clinical risk factors with and without DXA for osteoporosis screening in postmenopausal women

BACKGROUND

According to several guidelines, the assessment of postmenopausal fracture risk should be based on clinical risk factors (CRFs) and bone density. Because measurement of bone density by dual x-ray absorptiometry (DXA) is quite expensive, there has been increasing interest to estimate fracture risk by CRFs.

OBJECTIVE

The aim of this study was to determine the cost-effectiveness of osteoporosis screening of CRFs with and without DXA compared with no screening in postmenopausal women in Germany.

METHODS

A cost-utility analysis and a budget-impact analysis were performed from the perspective of the statutory health insurance. A Markov model simulated costs and benefits discounted at 3% over lifetime.

RESULTS

Cost-effectiveness of CRFs compared with no screening is euro4607, euro21,181, and euro10,171 per quality-adjusted life-year (QALY) for 60-, 70-, and 80-year-old women, respectively. Cost-effectiveness of DXA plus CRFs compared with CRFs alone is euro20,235 for 60-year-old women. In women above the age of 70, DXA plus CRFs dominates CRFs alone. DXA plus CRFs results in annual costs of euro175 million, or 0.4% of the statutory health insurance's annual budget.

CONCLUSION

Funders should be careful in adopting a strategy based on CRFs alone instead of DXA plus CRFs. Only if DXA is not available, assessing CRFs only is an acceptable option in predicting a woman's risk of fracture.

Bone signaling pathways and treatment of osteoporosis

Osteoporotic fractures are a major healthcare burden costing over US$50 billion/per year. Bone turnover is a continuous process regulated by the coupled activities of osteocytes, osteoclasts and osteoblasts that maintain bone mass and strength. Osteoclastic bone resorption is regulated by the RANKL/osteoprotegerin/RANK pathway, while osteoblastic bone formation is controlled by canonical Wnt signaling. Antiresorptive bisphosphonates remain the mainstay of treatment but recombinant parathyroid hormone is increasingly being used as an anabolic agent. Nevertheless, these drugs are limited by patient compliance, efficacy and cost. Cathepsin K inhibitors and RANKL antibodies have been developed as new antiresorptive drugs, while short-acting calcilytics and antibodies to Dickkopf-1 and sclerostin are promising anabolics. The recent identification of adipocytes and duodenal enterochromaffin cells as novel regulators of bone mass represent exciting opportunities for future drug development.

[Austrian guidance for the pharmacological treatment of osteoporosis in postmenopausal women--update 2009]

Osteoporosis is a systemic skeletal disease characterized by diminished bone mass and deterioration of bone microarchitecture, leading to increased fragility and subsequent increased fracture risk. Therapeutic measures therefore aim at reducing individual fracture risk. In Austria, the following drugs, all of which have been proven to reduce fracture risk, are currently registered for the treatment of postmenopausal osteoporosis: alendronate, risedronate, etidronate, ibandronate, raloxifene, teriparatide (1-34 PTH), 1-84 PTH, strontium ranelate and salmon calcitonin. Fluorides are still available, but their role in daily practice has become negligible. Currently, there is no evidence that a combination of two or more of these drugs could improve anti-fracture potency. However, treatment with PTH should be followed by the treatment with an anticatabolic drug such as bisphosphonates. Calcium and vitamin D constitute an important adjunct to any osteoporosis treatment.

Development and validation of a Markov microsimulation model for the economic evaluation of treatments in osteoporosis

OBJECTIVE

Markov models are increasingly used in economic evaluations of treatments for osteoporosis. Most of the existing evaluations are cohort-based Markov models missing comprehensive memory management and versatility. In this article, we describe and validate an original Markov microsimulation model to accurately assess the cost-effectiveness of prevention and treatment of osteoporosis.

METHODS

We developed a Markov microsimulation model with a lifetime horizon and a direct health-care cost perspective. The patient history was recorded and was used in calculations of transition probabilities, utilities, and costs. To test the internal consistency of the model, we carried out an example calculation for alendronate therapy. Then, external consistency was investigated by comparing absolute lifetime risk of fracture estimates with epidemiologic data.

RESULTS

For women at age 70 years, with a twofold increase in the fracture risk of the average population, the costs per quality-adjusted life-year gained for alendronate therapy versus no treatment were estimated at €9105 and €15,325, respectively, under full and realistic adherence assumptions. All the sensitivity analyses in terms of model parameters and modeling assumptions were coherent with expected conclusions and absolute lifetime risk of fracture estimates were within the range of previous estimates, which confirmed both internal and external consistency of the model.

CONCLUSION

Microsimulation models present some major advantages over cohort-based models, increasing the reliability of the results and being largely compatible with the existing state of the art, evidence-based literature. The developed model appears to be a valid model for use in economic evaluations in osteoporosis.

The cost-effectiveness of an RCT to establish whether 5 or 10 years of bisphosphonate treatment is the better duration for women with a prior fracture

PURPOSE

Five years of bisphosphonate treatment have proven efficacy in reducing fractures. Concerns exist that long-term bisphosphonate treatment may actually result in an increased number of fractures. This study evaluates, in the context of England and Wales, whether it is cost-effective to conduct a randomized controlled trial (RCT) and what sample size may be optimal to estimate the efficacy of bisphosphonates in fracture prevention beyond 5 years.

METHOD

An osteoporosis model was constructed to evaluate the cost-effectiveness of extending bisphosphonate treatment from 5 years to 10 years. Two scenarios were run. The 1st uses long-term efficacy data from published literature, and the 2nd uses distributions elicited from clinical experts.

RESULTS

of a proposed RCT were simulated. The expected value of sample information technique was applied to calculate the expected net benefit of sampling from conducting such an RCT at varying levels of participants per arm and to compare this with proposed trial costs. Results. Without further information, the better duration of bisphosphonate treatment was estimated to be 5 years using the published data but 10 years using the elicited expert opinions, although in both cases uncertainty was substantial. The net benefit of sampling was consistently high when between 2000 and 5000 participants per arm were recruited.

CONCLUSIONS

An RCT to evaluate the long-term efficacy of bisphosphonates in fracture prevention appears to be cost-effective for informing decision making in England and Wales.

The cost-effectiveness of alendronate in the management of osteoporosis

The National Institute for Health and Clinical Excellence (NICE) in the UK has recently issued health economic appraisals for the primary and secondary prevention of osteoporotic fracture that are more restrictive than previous guidelines for the management of osteoporosis despite a marked reduction of the cost of intervention. The aim of the present study was to examine the cost-effectiveness of the bisphosphonate, alendronate for the prevention and treatment of fractures associated with osteoporosis. A second aim was to investigate reasons for any disparities in cost-effectiveness between our findings and the NICE appraisals. We compared the effects of alendronate 70 mg weekly by mouth for 5 years with no treatment in postmenopausal women with clinical risk factors for fracture and computed the incremental cost-effectiveness ratio (ICER) using a lifetime simulation model based on Markov cohort methodology. A sensitivity analysis examined other common interventions. Using a threshold of pound sterling 30,000 and pound sterling 20,000 per quality of life-year (QALY) gained to determine cost-effectiveness, alendronate was cost-effective for the primary prevention of fracture in women with osteoporosis irrespective of age as was treatment of women with a prior fragility fracture irrespective of BMD. Cost-effective scenarios were also found in women with strong risk factors for fracture with a bone mineral density value above the threshold for osteoporosis. The results were robust over reasonable assumptions in sensitivity analysis. We conclude that alendronate is a cost-effective agent for the prevention and treatment of fractures associated with osteoporosis. These findings, suitable for informing practice guidance, contrast with recent appraisals from NICE.