Economic evaluation of dabigatran etexilate for the prevention of venous thromboembolism after total knee and hip replacement surgery. Clin Ther. 2009;31:194-212. [PMID: 19243718 DOI: 10.1016/j.clinthera.2009.01.001]

Incremental net monetary benefit of direct oral anticoagulants for the prevention of venous thromboembolism after total knee or hip replacement: A systematic review and meta-analysis

INTRODUCTION

This meta-analysis was conducted to quantitatively pool the incremental net benefit (INB) of using direct oral anticoagulants (DOACs) for the prevention of venous thromboembolism (VTE) in patients undergoing total knee or hip replacements (TKR or THR).

MATERIALS AND METHODS

We performed a comprehensive search in several databases published before June 2021. Studies were included if they were cost-effectiveness analyses reporting cost per quality-adjusted life-year or life-year of DOACs compared to low molecular-weight heparins (LMWHs) or other anticoagulant agents for the prevention of VTE after TKR or THR. Risk of bias was also assessed using the biases in economic studies (ECOBIAS) checklist. Various monetary units were converted to purchasing power parity, adjusted to 2020 US dollars. The INBs were pooled across studies using a random-effects model, stratified by high-income countries (HICs) and low- and middle-income countries (LMICs). Heterogeneity was assessed using the I² statistic.

RESULTS

A total of 49 comparisons (TKR = 25 and THR = 24) from 16 studies was included. In HICs, DOACs were cost-effective compared to LMWHs from the health care system/payer perspective for the prevention of VTE after both TKR and THR with corresponding INBs (95 % CI; I²) of $231.91 ($178.71, $285.11; 0 %) and $254.99 ($159.20, $350.77; 27.79 %), respectively. In LMICs, DOACs were not cost-effective compared to LMWHs for both TKR and THR with the INBs of $94.13 (-$40.21, $228.47; 97.04 %) and $80.55 (-$157.37, $318.47; 99.78 %), respectively. No evidence of small-study effects was identified in any analyses. The cost-effectiveness of using DOACs for TKR and THR in HICs was robust across a series of sensitivity analyses.

CONCLUSIONS

DOACs were cost-effective as compared to LMWHs for VTE prophylaxis following TKR and THR surgeries in HICs. Further studies from LMICs are warranted.

Direct oral anticoagulants versus low molecular weight heparins for the treatment of cancer-associated thrombosis: a cost-effectiveness analysis

BACKGROUND

Recently, direct oral anticoagulants (DOACs) have been included in guidelines for the treatment of cancer-associated thrombosis (CAT) to be extended to suitable cancer patients. The purpose of this study was to compare the cost-effectiveness of using DOACs and low molecular weight heparins (LMWHs) for treating CAT from the perspective of the Chinese healthcare system.

METHODS

A Markov model was constructed to estimate the cost-effectiveness of the two strategies with a 6-month and 5-year time horizon. Input parameters were either sourced from the clinical trial, published literature. The primary outcome of the model was reported as incremental cost-effectiveness ratios (ICERs). Sensitivity analyses were performed to test model uncertainty.

RESULTS

The 6-month cost of DOACs was $ 654.65 with 0.40 quality adjusted life-years (QALYs) while the 6-month cost of LMWHs was $USD 1719.31 with 0.37 QALYs. Similarly, treatment with DOACs had a lower cost ($USD 657.85 vs. $USD 1716.56) and more health benefits (0.40 QALYs vs. 0.37 QALYs) than treatment with LMWHs in a subgroup of patients with gastrointestinal malignancy. We found treatment with DOACs would result in a large reduction in cost ($USD 1447.22 vs. $USD 3374.70) but a small reduction in QALYs (3.07 QALYs vs. 3.09 QALYs) compared with LMWHs over a 5-year time frame, resulting in an ICER of $USD 112895.50/QALYs. Sensitivity analysis confirmed the robustness of the results.

CONCLUSION

As compared to LMWHs, DOACs can be a cost-saving anticoagulant choice for the treatment of CAT in the general oncology population and gastrointestinal malignancy population.

Economic Evaluation of New Oral Anticoagulants in Prevention of Venous Thrombosis Following Joint Replacement Surgery: A Systematic Review

PURPOSE

The main purpose of prescribing oral anticoagulants in patients undergoing total knee and total hip replacement surgery is to prevent venous thromboembolism (VTE). The present study aimed to summarize evidence from economic evaluations regarding new oral anticoagulants (NOACs) used in VTE prophylaxis after joint replacement surgery.

METHODS

To obtain relevant literature on economic evaluations of NOACs used in the prevention of VTE following joint replacement surgery, we searched the Cochrane Library, PubMed, Web of Science, Embase, and Scopus, as well as specialized economic evaluation databases, for articles published from January 2008 to December 2019. Next, 2 reviewers screened the titles and abstracts of studies, extracted data from the full-text articles, and assessed the quality of the methodologies using the Quality of Health Economic Studies checklist.

FINDINGS

Twenty-eight studies of economic evaluations met the inclusion criteria of the research. The quality assessment showed that 20 articles had scores within the range of 75 to 100 (high quality), and 9 studies had scores within the range of 50 to 74 (moderate quality). All of the identified studies had been carried out based on modelling, and 23 studies used decision trees to model acute events after surgery. In addition, 20 studies utilized a Markov model to capture long-term complications of VTE. The results showed that rivaroxaban was more cost-effective than apixaban and dabigatran from a perspective of the health care system in the prevention of VTE after total knee and total hip replacement surgery. In addition, apixaban was associated with a lower risk for bleeding events than other NOACs, making it the most cost-effective NOAC from the perspective of the payer.

IMPLICATIONS

The results suggest that NOACs are cost-effective alternatives to low-molecular-weight heparins. Rivaroxaban and dabigatran were assessed as the most and least cost-effective prophylaxis options, respectively, after joint replacement surgery for the prevention of VTE. It is recommended that future research be conducted on economic evaluations of edoxaban.

Different strategies for pharmacological thromboprophylaxis for lower-limb immobilisation after injury: systematic review and economic evaluation

BACKGROUND

Thromboprophylaxis can reduce the risk of venous thromboembolism (VTE) during lower-limb immobilisation, but it is unclear whether or not this translates into meaningful health benefit, justifies the risk of bleeding or is cost-effective. Risk assessment models (RAMs) could select higher-risk individuals for thromboprophylaxis.

OBJECTIVES

To determine the clinical effectiveness and cost-effectiveness of different strategies for providing thromboprophylaxis to people with lower-limb immobilisation caused by injury and to identify priorities for future research.

DATA SOURCES

Ten electronic databases and research registers (MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Database of Abstracts of Review of Effects, the Cochrane Central Register of Controlled Trials, Health Technology Assessment database, NHS Economic Evaluation Database, Science Citation Index Expanded, ClinicalTrials.gov and the International Clinical Trials Registry Platform) were searched from inception to May 2017, and this was supplemented by hand-searching reference lists and contacting experts in the field.

REVIEW METHODS

Systematic reviews were undertaken to determine the effectiveness of pharmacological thromboprophylaxis in lower-limb immobilisation and to identify any study of risk factors or RAMs for VTE in lower-limb immobilisation. Study quality was assessed using appropriate tools. A network meta-analysis was undertaken for each outcome in the effectiveness review and the results of risk-prediction studies were presented descriptively. A modified Delphi survey was undertaken to identify risk predictors supported by expert consensus. Decision-analytic modelling was used to estimate the incremental cost per quality-adjusted life-year (QALY) gained of different thromboprophylaxis strategies from the perspectives of the NHS and Personal Social Services.

RESULTS

Data from 6857 participants across 13 trials were included in the meta-analysis. Thromboprophylaxis with low-molecular-weight heparin reduced the risk of any VTE [odds ratio (OR) 0.52, 95% credible interval (CrI) 0.37 to 0.71], clinically detected deep-vein thrombosis (DVT) (OR 0.40, 95% CrI 0.12 to 0.99) and pulmonary embolism (PE) (OR 0.17, 95% CrI 0.01 to 0.88). Thromboprophylaxis with fondaparinux (Arixtra®, Aspen Pharma Trading Ltd, Dublin, Ireland) reduced the risk of any VTE (OR 0.13, 95% CrI 0.05 to 0.30) and clinically detected DVT (OR 0.10, 95% CrI 0.01 to 0.94), but the effect on PE was inconclusive (OR 0.47, 95% CrI 0.01 to 9.54). Estimates of the risk of major bleeding with thromboprophylaxis were inconclusive owing to the small numbers of events. Fifteen studies of risk factors were identified, but only age (ORs 1.05 to 3.48), and injury type were consistently associated with VTE. Six studies of RAMs were identified, but only two reported prognostic accuracy data for VTE, based on small numbers of patients. Expert consensus was achieved for 13 risk predictors in lower-limb immobilisation due to injury. Modelling showed that thromboprophylaxis for all is effective (0.015 QALY gain, 95% CrI 0.004 to 0.029 QALYs) with a cost-effectiveness of £13,524 per QALY, compared with thromboprophylaxis for none. If risk-based strategies are included, it is potentially more cost-effective to limit thromboprophylaxis to patients with a Leiden thrombosis risk in plaster (cast) [L-TRiP(cast)] score of ≥ 9 (£20,000 per QALY threshold) or ≥ 8 (£30,000 per QALY threshold). An optimal threshold on the L-TRiP(cast) receiver operating characteristic curve would have sensitivity of 84-89% and specificity of 46-55%.

LIMITATIONS

Estimates of RAM prognostic accuracy are based on weak evidence. People at risk of bleeding were excluded from trials and, by implication, from modelling.

CONCLUSIONS

Thromboprophylaxis for lower-limb immobilisation due to injury is clinically effective and cost-effective compared with no thromboprophylaxis. Risk-based thromboprophylaxis is potentially optimal but the prognostic accuracy of existing RAMs is uncertain.

FUTURE WORK

Research is required to determine whether or not an appropriate RAM can accurately select higher-risk patients for thromboprophylaxis.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017058688.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Cost-Utility Analysis of Venous Thromboembolism Prophylaxis Strategies for People Undergoing Elective Total Hip and Total Knee Replacement Surgeries in the English National Health Service

Background: Major orthopedic surgery, such as elective total hip replacement (eTHR) and elective total knee replacement (eTKR), are associated with a higher risk of venous thromboembolism (VTE) than other surgical procedures. Little is known, however, about the cost-effectiveness of VTE prophylaxis strategies in people undergoing these procedures. Aim: The aim of this work was to assess the cost-effectiveness of these strategies from the English National Health Service perspective to inform NICE guideline (NG89) recommendations. Materials and Methods: Cost-utility analysis, using decision modeling, was undertaken to compare 15 VTE prophylaxis strategies for eTHR and 12 for eTKR, in addition to "no prophylaxis" strategy. The analysis complied with the NICE Reference Case. Structure and assumptions were agreed with the guideline committee. Incremental net monetary benefit (INMB) was calculated, vs. the model comparator (LMWH+ antiembolism stockings), at a threshold of £20,000/quality-adjusted life-year (QALY) gained. The model was run probabilistically. Deterministic sensitivity analyses (SAs) were undertaken to assess the robustness of the results. Results: The most cost-effective strategies were LMWH for 10 days followed by aspirin for 28 days (INMB = £530 [95% CI: -£784 to £1,103], probability of being most cost-effective = 72%) for eTHR, and foot pump (INMB = £353 [95% CI: -£101 to £665]; probability of being most cost-effective = 18%) for eTKR. There was considerable uncertainty regarding the cost-effectiveness ranking in the eTKR analysis. The results were robust to change in all SAs. Conclusions: For eTHR, LMWH (standard dose) for 10 days followed by aspirin for 28 days is the most cost-effective VTE prophylaxis strategy. For eTKR, the results are highly uncertain but foot pump appeared to be the most cost-effective strategy, followed closely by aspirin (low dose). Future research should focus on assessing cost-effectiveness of VTE prophylaxis in the eTKR population.

European Union-28: An annualised cost-of-illness model for venous thromboembolism

Annual costs for venous thromboembolism (VTE) have been defined within the United States (US) demonstrating a large opportunity for cost savings. Costs for the European Union-28 (EU-28) have never been defined. A literature search was conducted to evaluate EU-28 cost sources. Median costs were defined for each cost input and costs were inflated to 2014 Euros (€) in the study country and adjusted for Purchasing Power Parity between EU countries. Adjusted costs were used to populate previously published cost-models based on adult incidence-based events. In the base model, annual expenditures for total, hospital-associated, preventable, and indirect costs were €1.5–2.2 billion, €1.0–1.5 billion, €0.5–1.1 billion and €0.2–0.3 billion, respectively (indirect costs: 12 % of expenditures). In the long-term attack rate model, total, hospital-associated, preventable, and indirect costs were €1.8–3.3 billion, €1.2–2.4 billion, €0.6–1.8 billion and €0.2–0.7 billion (indirect costs: 13 % of expenditures). In the multiway sensitivity analysis, annual expenditures for total, hospital-associated, preventable, and indirect costs were €3.0–8.5 billion, €2.2–6.2 billion, €1.1–4.6 billion and €0.5–1.4 billion (indirect costs: 22 % of expenditures). When the value of a premature life-lost increased slightly, aggregate costs rose considerably since these costs are higher than the direct medical costs. When evaluating the models aggregately for costs, the results suggests total, hospital-associated, preventable, and indirect costs ranging from €1.5–13.2 billion, €1.0–9.7 billion, €0.5–7.3 billion and €0.2–6.1 billion, respectively. Our study demonstrates that VTE costs have a large financial impact upon the EU-28’s healthcare systems and that significant savings could be realised if better preventive measures are applied.

The cost-utility of dabigatran etexilate compared with warfarin in treatment and extended anticoagulation of acute VTE in the UK

The relative efficacy and safety of dabigatran etexilate and warfarin have been evaluated in two head-to-head, phase III, treatment of acute venous thromboembolism (VTE) trials, and one extended prophylaxis trial, in patients with high risk of recurrent VTE. Dabigatran etexilate demonstrated similar efficacy to warfarin, and was associated with a reduced risk of major or clinically relevant bleeds. Based on results of these trials, and real-life disease prognosis following discontinuation of anticoagulation treatment, we evaluated the cost-utility of dabigatran etexilate compared with warfarin in six months anticoagulation, and in extended, up to 24 months anticoagulation, in patients with acute VTE, acute deep-vein thrombosis (DVT) or acute, symptomatic, pulmonary embolism (PE). Costs were analysed from the perspective of the National Health Services (NHS) and Public Social Services (PSS) in England and Wales. Outcomes were quantified in quality-adjusted life years (QALY). The estimated incremental, lifetime cost/QALY gain following acute, symptomatic VTE (DVT or PE) was £1,252/QALY when dabigatran etexilate or warfarin were administered for up to six months treatment. In treatment of acute, symptomatic PE and in DVT respective ratios were £1,767/QALY and £1,075/QALY. In extended, up to 24 months anticoagulation, dabigatran etexilate projected costs/QALY of £8,242/QALY, when compared with warfarin. Results obtained herein were robust across a number of sensitivity analyses and suggest dabigatran etexilate to be a cost-effective alternative to current standard of care when evaluated in six months treatment and in extended anticoagulation following acute VTE (DVT and/or PE).

Benefit–risk profile of non-vitamin K antagonist oral anticoagulants in the management of venous thromboembolism

The prevention and treatment of venous thromboembolism (VTE) remains a clinical challenge, primarily owing to drawbacks associated with the use of heparins and vitamin K antagonists (VKAs). These and other factors, including a growing elderly population, mean that VTE presents a continuing burden to patients and physicians. Anticoagulant therapy is a fundamental approach for VTE management. Non- VKA oral anticoagulants, including the factor Xa inhibitors apixaban, edoxaban and rivaroxaban, and the thrombin inhibitor dabigatran, have been studied in phase III trials across a spectrum of thromboembolic disorders. These agents offer simplified care, with similar or improved efficacy and safety outcomes compared with heparins and vitamin K antagonists. There are several factors a physician must consider when prescribing an anticoagulant. An important consideration with all anticoagulant use is bleeding risk, especially in high-risk groups such as the elderly or those with renal impairment or cancer. In orthopaedic patients, other risks include a need for surgical revision or blood transfusion, or wound complications. Therefore, the clinical benefits of an anticoagulant should ideally be balanced with any risks associated with the therapy. Quantitative benefit–risk assessments are lacking, and owing to differences in trial design the non-VKA oral anticoagulants cannot be compared directly. Based on trial and “reallife” data, this review will summarise the clinical data for the non-VKA oral anticoagulants in the prevention and treatment of VTE, focusing on the balance between the benefits and risks of anticoagulation with these drugs, and their potential impact on VTE management.

Economic Evaluations of New Oral Anticoagulants for the Prevention of Venous Thromboembolism After Total Hip or Knee Replacement: A Systematic Review

BACKGROUND

Total hip replacement (THR) and total knee replacement (TKR) surgeries are being performed with increasing regularity and are associated with a high risk of developing a venous thromboembolism (VTE). New oral anticoagulants (NOACs) may be more effective at preventing VTEs but are associated with more bleeding events versus traditional anticoagulants.

OBJECTIVE

The objective of this systematic review was to identify published economic analyses of NOACs for primary VTE prophylaxis following THR and TKR surgeries, and to summarise the modelling techniques used and the cost-effectiveness results.

METHODS

Electronic searches of MEDLINE, EconLit and The Cochrane Library were performed from January 2008 to February 2015. Reference lists of included articles and reviews were examined for relevant studies.

RESULTS

Sixteen relevant economic analyses were identified, all of which used decision-tree structures to model acute events after surgery; 13 included a chronic-phase Markov module to capture long-term complications of VTE and recurrent VTE events. All studies included prophylaxis-related major bleeding events and captured both symptomatic and asymptomatic VTE-related events; nine studies distinguished between distal and proximal deep vein thrombosis events. Overall, rivaroxaban dominated enoxaparin in eight of 11 studies and dalteparin in one study, dabigatran dominated enoxaparin in five of seven studies and apixaban dominated enoxaparin in two of two studies. Rivaroxaban dominated dabigatran in four of four studies, apixaban dominated dabigatran in two of two studies and rivaroxaban dominated apixaban in one study.

CONCLUSIONS

The economic analyses showed reasonable consistency in the model structures used and the events captured. The results strongly suggested that NOACs are cost effective alternatives to low molecular-weight heparin. Dabigatran appeared to be the least cost effective NOAC. More research is needed to assess the cost effectiveness of apixaban and edoxaban.

Cost-Effectiveness of Different Strategies for the Prevention of Venous Thromboembolism After Total Hip Replacement in China

Introduction

The aim of this study was to evaluate the cost-effectiveness of rivaroxaban and apixaban versus enoxaparin for the universal prophylaxis of venous thromboembolism (VTE) and associated long-term complications in Chinese patients after total hip replacement (THR).

Methods

A decision model, which included both acute VTE (represented as a decision tree) and the long-term complications of VTE (represented as a Markov model), was developed to assess the economic outcomes of the three prophylactic strategies for Chinese patients after THR. Transition probabilities for acute VTE were derived from two randomized controlled studies, RECORD1 and ADVANCE3, of patients after THR. The transition probabilities of long-term complications after acute VTE, utilities, and costs were derived from the published literature and local healthcare settings. One-way and probabilistic sensitivity analyses (PSA) were performed to test the uncertainty concerning the model parameters. The quality-adjusted life years (QALYs) and direct medical costs were reported over a 5-year horizon, and incremental cost-effectiveness ratios (ICERs) were also calculated.

Results

Thromboprophylaxis with apixaban was estimated to have a higher cost (US $178.70) and more health benefits (0.0025 QALY) than thromboprophylaxis with enoxaparin over a 5-year time horizon, which resulted in an ICER of US $71,244 per QALY gained and was more than three times the GDP per capita of China in 2014 (US $22,140). Owing to the higher cost and lower generated QALYs, rivaroxaban was inferior to enoxaparin among post-THR patients. The sensitivity analyses confirmed these results.

Conclusions

The analysis found that apixaban was not cost-effective and that rivaroxaban was inferior to enoxaparin. This finding indicates that compared with enoxaparin, the use of apixaban for VTE prophylaxis after THR does not represent a good value for the cost at the acceptable threshold in China; in addition, the cost of rivaroxaban was higher with lower QALYs.

Oral dabigatran etexilate versus enoxaparin for venous thromboembolism prevention after total hip arthroplasty: pooled analysis of two phase 3 randomized trials

Background

Two phase 3 trials compared 28–35 days of treatment with oral dabigatran 220 mg or 150 mg (RE-NOVATE) or 220 mg (RE-NOVATE II) once daily with subcutaneous enoxaparin 40 mg once daily for prevention of venous thromboembolism (VTE) after elective total hip arthroplasty.

Methods

This prespecified pooled analysis compared the outcomes for the dabigatran 220 mg dose with enoxaparin, which included 4,374 patients. Total VTE (venographic and symptomatic) plus all-cause mortality (primary efficacy), major VTE (proximal deep vein thrombosis [DVT] or non-fatal pulmonary embolism) plus VTE-related death, and bleeding events were evaluated. Efficacy analysis was based on the modified intention-to-treat (ITT) population and safety analysis was based on all treated patients. The common risk difference (RD) for dabigatran versus enoxaparin was estimated using a fixed effects model.

Results

Total VTE and all-cause mortality occurred in 6.8 % (114/1,672) and 7.7 % (129/1,682) (RD:–0.8 %, 95 % confidence interval [CI] –2.6 to 0.9) for dabigatran and enoxaparin, respectively. Major VTE plus VTE-related mortality occurred in 2.7 % (46/1,714) and 4.0 % (69/1,711) (RD: –1.4 %, 95 % CI –2.6 to –0.2) of patients receiving dabigatran 220 mg and enoxaparin, respectively. Major bleeding occurred in 1.7 % (37/2,156) and 1.3 % (27/2,157) (RD: 0.5 %, 95 % CI –0.2 to 1.2), for dabigatran and enoxaparin respectively.

Conclusions

Extended prophylaxis with oral dabigatran 220 mg once daily was as effective as enoxaparin 40 mg once daily in reducing the risk of total VTE and all-cause mortality after total hip arthroplasty, with a similar bleeding profile. The clinically relevant outcome of major VTE and VTE-related death was significantly reduced with dabigatran versus enoxaparin.

Trial registration

NCT00657150 and NCT00168818

Venous thromboembolism prophylaxis after total joint arthroplasty

Venous thromboembolism (VTE) prophylaxis after total joint arthroplasty is considered best practice. However, over the past 5 years, there has been considerable debate about the ideal prophylactic regimen or modality. The American Academy of Orthopaedic Surgeons and the American College of Chest Physicians published their most recent clinical practice guidelines about VTE prophylaxis in 2011 and 2012, respectively. In addition, the Surgical Care Improvement Project published their latest recommendations in 2014. In this review, commonly used VTE prophylaxis options and the latest clinical guidelines will be discussed.

Pharmacoeconomic evaluation of dabigatran, rivaroxaban and apixaban versus enoxaparin for the prevention of venous thromboembolism after total hip or knee replacement in Spain

BACKGROUND

Patients undergoing total hip replacement (THR) or total knee replacement (TKR) surgery are at high risk of developing venous thromboembolism (VTE). Thromboprophylaxis with low-molecular-weight heparin, such as enoxaparin, is standard of care in these patients. Recently, three direct oral anticoagulants (DOACs; dabigatran, rivaroxaban and apixaban), have been approved for this indication, but their cost effectiveness is still unclear as it has usually been extrapolated from surrogate venographic outcomes in clinical trials.

OBJECTIVE

To conduct a pharmacoeconomic evaluation of the DOACs versus subcutaneous (SC) enoxaparin for the prevention of VTE after THR or TKR surgery.

METHODS

A decision-tree model was developed using TreeAge Pro 2011 to compare the cost utility and cost effectiveness of the DOACs with SC enoxaparin, with separate models for THR and TKR over a 3-month postoperative time horizon from the perspective of the Spanish National Health System. The probabilities of events (symptomatic VTE, clinically relevant bleedings, heparin-induced thrombocytopenia and deaths) were derived from a systematic review and meta-analysis. We used local cost estimates (€2013) and utility values were obtained from the literature. We reported costs, quality-adjusted life-years (QALYs) and symptomatic VTE events. We conducted sensitivity analyses to evaluate parameter uncertainty.

RESULTS

The average costs per 1,000 patients treated with enoxaparin were higher than costs incurred by dabigatran, rivaroxaban and apixaban in THR (€435,208 vs. €283,574, €257,900 and €212,472, respectively) and TKR (€336,550 vs. €219,856, €251,734 and €201,946, respectively), with cost savings ranging from €151,634 to €222,766 in THR, and from €84,816 to €134,604 in TKR. Cost differences were largely driven by differences in costs associated with drug administration. The average QALYs per 1,000 patients treated were very similar for enoxaparin, dabigatran, rivaroxaban and apixaban in THR (199.34, 198.83, 199.08 and 199.68, respectively) and TKR (198.95, 199.41, 198.75 and 199.97, respectively). Rivaroxaban (in TKR and THR) and apixaban (in THR) avoided additional symptomatic VTE events compared with enoxaparin. Sensitivity analyses generally supported the robustness of the analysis to changes in model parameters.

CONCLUSIONS

Our model suggests, based on its underlying assumptions and data, that the DOACs are cost-saving alternatives to SC enoxaparin for the prevention of VTE after THR or TKR, in the Spanish healthcare setting.

New oral pharmacotherapeutic agents for venous thromboprophylaxis after total hip arthroplasty

Patients undergoing total hip arthroplasty (THA) are at high risk for developing venous thromboembolism and, therefore, require short term prophylaxis with antithrombotic agents. Recently, target specific oral anticoagulants (TSOA) including the direct thrombin inhibitor, dabigatran, and the factor Xa inhibitors rivaroxaban, apixaban, and edoxaban have been approved for THA thrombopropylaxis in various countries. The TSOAs provide a rapid acting, oral alternative to parenteral agents including low-molecular weight heparins (LMWH) and fondaparinux; and compared to warfarin, they do not require routine laboratory monitoring and possess much fewer drug-drug interactions. Based on phase III clinical studies, TSOAs have established themselves as an effective and safe option for thromboprophylaxis after THA compared to LMWH, particularly enoxaparin, but require additional evaluation in specific populations such as the renally impaired or elderly. The ability to monitor and reverse these TSOAs in the case of bleeding complications or suspected sub- or supra-therapeutic anticoagulation is of importance, but remains investigational. This review will focus on the drug-specific characteristics, efficacy, safety, and economic impact of the TSOAs for thromboprophylaxis following THA, as well as the aspects of therapeutic monitoring and anticoagulation reversal in the event of bleeding complications or a need for urgent reversal.

Systematic review of drug administration costs and implications for biopharmaceutical manufacturing

BACKGROUND

The acquisition costs of biologic drugs are often considered to be relatively high compared with those of nonbiologics. However, the total costs of delivering these drugs also depend on the cost of administration. Ignoring drug administration costs may distort resource allocation decisions because these affect cost effectiveness.

OBJECTIVES

The objectives of this systematic review were to develop a framework of drug administration costs that considers both the costs of physical administration and the associated proximal costs; and, as a case example, to use this framework to evaluate administration costs for biologics within the UK National Health Service (NHS).

METHODS

We reviewed literature that reported estimates of administration costs for biologics within the UK NHS to identify how these costs were quantified and to examine how differences in dosage forms and regimens influenced administration costs. The literature reviewed were identified by searching the Centre for Review and Dissemination Databases (DARE, NHS EED and HTA); EMBASE (The Excerpta Medica Database); MEDLINE (using the OVID interface); Econlit (EBSCO); Tufts Medical Center Cost Effectiveness Analysis (CEA) Registry; and Google Scholar.

RESULTS

We identified 4,344 potentially relevant studies, of which 43 studies were selected for this systematic review. We extracted estimates of the administration costs of biologics from these studies. We found evidence of variation in the way that administration costs were measured, and that this affected the magnitude of costs reported, which could then influence cost effectiveness.

CONCLUSIONS

Our findings suggested that manufacturers of biologic medicines should pay attention to formulation issues and their impact on administration costs, because these affect the total costs of healthcare delivery and cost effectiveness.

NEW ANTICOAGULANTS AS THROMBOPROPHYLAXIS AFTER TOTAL HIP OR KNEE REPLACEMENT

Objectives: Due to a high risk of thromboembolism in patients undergoing major orthopedic surgery, it has become standard practice to give thromboprophylactic treatment. We assessed the relative efficacy and cost-effectiveness of two new oral anticoagulants, rivaroxaban and dabigatran, relative to subcutaneous enoxaparin for the prevention of thromboembolism after total hip replacement (THR) and total knee replacement surgery (TKR).

Methods: We conducted a systematic review of the literature to assess efficacy and safety, and evaluated quality of documentation using GRADE. Cost-effectiveness was assessed by developing a decision model. The model combined two modules; a decision tree for the short-term prophylaxis and a Markov model for the long-term complications and survival gain.

Results: For rivaroxaban compared with enoxaparin, we found statistically significant decreases in deep vein thrombosis, but also a trend toward increased risk of major bleeding. For mortality and pulmonary embolism there were no statistically significant differences between the treatments. We did not find statistically significant differences between dabigatran and enoxaparin for our efficacy and safety outcomes. Assuming a willingness to pay of EUR62,500 per QALY, rivaroxaban following THR had a probability of 38 percent, and enoxaparin following TKR had a probability of 34 percent of being cost-effective. Clinical efficacy had the greatest impact on decision uncertainty.

Conclusions: Dabigatran and rivaroxaban are comparable with enoxaparin following THR and TKR regarding the efficacy and safety outcomes. However, there is great uncertainty regarding which strategy is the most cost-effective. More research on clinical efficacy of rivaroxaban and dabigatran is likely to change our results.

The cost-effectiveness of total joint arthroplasty: a systematic review of published literature

OBJECTIVE

To summarise the state of the literature evaluating the cost-effectiveness of elective total hip and knee arthroplasty (THA and TKA).

METHODS

We conducted a systematic review of published cost-effectiveness analyses of THA and TKA. To limit our search to high-quality published papers, we selected those papers included in the Cost-Effectiveness Analysis Registry (created by the Center for the Evaluation of Value and Risk in Health at Tufts University) and augmented the search with papers listed in PubMed. The data abstracted included incremental cost-effectiveness ratios, perspective of the analysis, time frame, sensitivity analyses conducted, and utility assessment. All cost-effectiveness ratios were converted to 2011 USD.

RESULTS

Seven studies presenting cost-effectiveness ratios for TKA and six studies for THA were included in our review. All economic evaluations of TKA were published between 2006 and 2012. By contrast, THA studies were published between 1996 and 2008. Out of the 13 studies evaluated in this review, four were from the societal perspective and eight were from the payer perspective. Five studies spanned the lifetime horizon. Of the selected studies, six used probabilistic sensitivity analysis to address uncertainty in data parameters. Both procedures have been shown to be highly cost-effective from the societal perspective over the entire lifespan.

CONCLUSION

THA and TKA have been found to be highly cost-effective in a number of high-quality studies. Further analyses are needed on the cost-effectiveness of alternative surgical options, particularly osteotomy. Future economic evaluations should address the expanding indications of THA and TKA to younger, more physically active individuals.

Pharmacoeconomic implications of thromboprophylaxis with new oral anticoagulants after total hip or knee replacement in the USA

INTRODUCTION

Adequate thromboprophylaxis after total hip or knee replacement (THR or TKR) is essential to reduce the incidence of venous thromboembolism (VTE) and its associated complications. Although effective, traditional anticoagulants are associated with a considerable economic burden, particularly when used outside the hospital setting. This article explores whether newer oral anticoagulants can reduce costs of VTE prophylaxis and therapy.

AREAS COVERED

Cost associated with vitamin K antagonists; indirect costs associated with complicated or inconvenient anticoagulation regimens, non-adherence and associated complications; potential of the newer oral anticoagulants, including direct thrombin inhibitors and direct factor Xa inhibitors, to produce indirect cost savings after THR or TKR through a potential reduction in VTE rates and administration and monitoring costs.

EXPERT OPINION

The use of new anticoagulants for VTE prophylaxis after THR or TKR can result in direct and indirect cost savings through improved efficacy by reducing VTE rates and decreased drug administration and monitoring costs compared with traditional anticoagulants. Future research will need to focus on cost analyses driven by clinical outcomes measured on the performance of these agents in actual clinical practice.

Value-of-information analysis to reduce decision uncertainty associated with the choice of thromboprophylaxis after total hip replacement in the Irish healthcare setting

BACKGROUND

The National Centre for Pharmacoeconomics, in collaboration with the Health Services Executive, considers the cost effectiveness of all new medicines introduced into Ireland. Health Technology Assessments (HTAs) are conducted in accordance with the existing agreed Irish HTA guidelines. These guidelines do not specify a formal analysis of value of information (VOI).

OBJECTIVE

The aim of this study was to demonstrate the benefits of using VOI analysis in decreasing decision uncertainty and to examine the viability of applying these techniques as part of the formal HTA process for reimbursement purposes within the Irish healthcare system.

METHOD

The evaluation was conducted from the Irish health payer perspective. A lifetime model evaluated the cost effectiveness of rivaroxaban, dabigatran etexilate and enoxaparin sodium for the prophylaxis of venous thromboembolism after total hip replacement. The expected value of perfect information (EVPI) was determined directly from the probabilistic analysis (PSA). Population-level EVPI (PEVPI) was determined by scaling up the EVPI according to the decision incidence. The expected value of perfect parameter information (EVPPI) was calculated for the three model parameter subsets: probabilities, preference weights and direct medical costs.

RESULTS

In the base-case analysis, rivaroxaban dominated both dabigatran etexilate and enoxaparin sodium. PSA indicated that rivaroxaban had the highest probability of being the most cost-effective strategy over a threshold range of &U20AC;0-&U20AC;100 000 per QALY. At a threshold of &U20AC;45 000 per QALY, the probability that rivaroxaban was the most cost-effective strategy was 67%. At a threshold of &U20AC;45 000 per QALY, assuming a 10-year decision time horizon, the PEVPI was &U20AC;11.96 million and the direct medical costs subset had the highest EVPPI value (&U20AC;9.00 million at a population level). In order to decrease uncertainty, a more detailed costing study was undertaken. In the subsequent analysis, rivaroxaban continued to dominate both comparators. In the PSA, rivaroxaban continued to have the highest probability of being optimal over the threshold range &U20AC;0-&U20AC;100 000 per QALY. At &U20AC;45 000 per QALY, the probability that rivaroxaban was the most cost-effective strategy increased to 80%. At &U20AC;45 000 per QALY, the 10-year PEVPI decreased to &U20AC;3.58 million and the population value associated with the direct medical costs fell to &U20AC;1.72 million.

CONCLUSION

This increase in probability of cost effectiveness, coupled with a substantially reduced potential opportunity loss could influence a decision maker's confidence in making a reimbursement decision. On discussions with the decision maker we now intend to incorporate the use of VOI into our HTA process.

Dabigatran etexilate: a review of its use for the prevention of venous thromboembolism after total hip or knee replacement surgery

Dabigatran etexilate (Pradaxa®, Pradax™, Prazaxa®) is indicated for the primary prevention of venous thromboembolic (VTE) events in adults who have undergone elective total hip replacement (THR) or total knee replacement (TKR) surgery. This article reviews the clinical efficacy and tolerability of oral dabigatran etexilate in patients undergoing major orthopaedic surgery, as well as summarizing its pharmacological properties and results of a cost-utility analysis. The discussion of clinical trial data focuses on comparative trials with the EU approved dosage regimen of once-daily subcutaneous enoxaparin sodium 40 mg. Dabigatran etexilate is an oral prodrug of the potent, rapidly acting, reversible, competitive inhibitor of thrombin, dabigatran. Dabigatran has predictable and consistent anticoagulant effects and does not require routine coagulation monitoring or dose titration. In the large, randomized, double-blind, phase III, noninferiority trials, RE-MODEL, RE-NOVATE and RE-NOVATE II, oral dabigatran etexilate, at dosages of 150 and 220 mg once daily, initiated postoperatively was shown to be noninferior to subcutaneous enoxaparin sodium 40 mg once daily (initiated prior to surgery) with regard to the incidence of the composite of total VTE events and all-cause mortality in patients undergoing TKR or THR surgery. In general, oral dabigatran etexilate was well tolerated in clinical trials of patients undergoing major orthopaedic surgery. There were no significant between-group differences in bleeding complications, including major bleeding, clinically relevant non-major bleeding or minor bleeding between the dabigatran etexilate or enoxaparin sodium groups. In addition, a cost-utility analysis from the perspective of the UK National Health Service indicated that dabigatran etexilate 220 mg once daily is dominant (i.e. more effective and less costly) to enoxaparin sodium 40 mg once daily in patients undergoing THR or TKR. Additional head-to-head comparisons would be beneficial to more definitively position dabigatran etexilate relative to other available oral treatment options for VTE prophylaxis, such as rivaroxaban and apixaban. In the meantime, dabigatran etexilate offers a convenient, effective and generally well tolerated treatment option for the prophylaxis of VTE in patients undergoing TKR and THR surgery.

Venous thromboembolism: annualised United States models for total, hospital-acquired and preventable costs utilising long-term attack rates

Healthcare reform is upon the United States (US) healthcare system. Prioritisation of preventative efforts will guide necessary transitions within the US healthcare system. While annual deep-vein thrombosis (DVT) costs have recently been defined at the US national level, annual pulmonary embolism (PE) and venous thromboembolism (VTE) costs have not yet been defined. A decision tree and cost model were developed to estimate US health care costs for total PE, total hospital-acquired PE, and total hospital-acquired "preventable" PE. The previously published DVT cost model was modified, updated and combined with the PE cost model to elucidate the same three categories of costs for VTE. Direct and indirect costs were also delineated. For VTE in the base model, annual cost ranges in 2011 US dollars for total, hospital- acquired, and hospital-acquired "preventable" costs and were $13.5-$27.2, $9.0-$18.2, and $4.5-$14.2 billion, respectively. The first sensitivity analysis, with higher incidence rates and costs, demonstrated annual US total, hospital-acquired, and hospital-acquired "preventable" VTE costs ranging from $32.1-$69.3, $23.7-$51.5, and $11.9-$39.3 billion, respectively. The second sensitivity analysis with long-term attack rates (LTAR) for recurrent events and post-thrombotic syndrome and chronic pulmonary thromboembolic hypertension demonstrated annual US total, hospital-acquired, and hospital-acquired "preventable" VTE costs ranging from $15.4-$34.4, $10.3-$25.4, and $5.1-$19.1 billion, respectively. PE costs comprised a majority of the VTE costs. Prioritisation of effective VTE preventative strategies will reduce significant costs, morbidity and mortality within the US healthcare system. The cost models may be utilised to estimate other countries' costs or VTE-specific disease states.

Elective hip and knee arthroplasty and the effect of rivaroxaban and enoxaparin thromboprophylaxis on wound healing

INTRODUCTION

Rivaroxaban is the first licensed oral direct inhibitor of factor Xa. Recent studies from the RECORD trials suggest rivaroxaban has superior efficacy compared to enoxaparin in preventing venous thromboembolism (VTE) with no significant increase in the major bleeding risk. Concerns remain regarding the incidence of minor bleeding, consequent delayed wound healing and subsequent risk of infection. The aim of this observational study was to assess the incidence of post-operative complications in patients receiving either rivaroxaban or enoxaparin thromboprophylaxis following elective hip and knee arthroplasty.

METHODS

A total of 258 patients undergoing elective total hip or knee arthroplasty within one NHS Trust were included. A total of 202 subjects (mean age, 70.7 years ± 10.0, 43 % men) received a daily dose of 10 mg of oral rivaroxaban and 56 (mean age, 70.9 years ± 9.8, 39 % men) had a daily subcutaneous injection of 40 mg of enoxaparin as thromboprophylaxis. Endpoints included VTE (deep vein thrombosis and pulmonary embolism), haemorrhagic wound complications, hospital re-admission, requirement for blood transfusion, minor and major bleeding and death.

RESULTS

There were no significant differences in the incidence of VTE, requirement for blood transfusion and readmission rate between rivaroxaban and enoxaparin-treated patients. The incidence of minor bleeding (2.0 vs. 0 %) and haemorrhagic wound complications (5.0 vs. 1.8 %) were non-significantly higher in the rivaroxaban-treated group. There were no cases of pulmonary embolism, major bleeding or death in either group.

CONCLUSION

Our experience with rivaroxaban in elective hip and knee arthroplasty showed no significant difference in the incidence of VTE or major bleeding. There was, however, a tendency to greater risk of minor bleeding and wound complications that were largely haemorrhagic in nature, which may have reached significance in a larger study.

Oral thromboprophylaxis following total hip replacement: the issue of compliance

INTRODUCTION

Thirty-five to 40 days' thromboprophylaxis is recommended following total hip replacement (THR). Low molecular weight heparin (LMWH) injected by a health professional ensures good compliance. Compliance with recent oral anticoagulants has not been precisely assessed. Oral self-administration, without coagulation monitoring tests, may be a worrying issue in the management of what is a potentially catastrophic adverse event, without prodromal symptoms alerting the patient to the need for regular intake throughout the prescription period.

HYPOTHESIS

It was hypothesized that compliance with these new oral anticoagulants is good over the entire treatment period.

PATIENTS AND METHOD

The present cohort study prospectively assessed compliance with oral medication (two capsules of dabigatran etexilate [Pradaxa(®)] per day in a single dose at a set time) following THR. An electronic device continuously monitored the day and time of extraction of capsules from the package. All included patients underwent clinical and echo-Doppler examination at day 30±5 after the start of the study.

RESULTS

Fifty-six patients were included at their discharge home. Overall compliance was 98.1% (3,188/3246 capsules correctly taken), falling off slightly over time but never below 97.1%. One patient was diagnosed with symptomatic thrombophlebitis 34 days postoperatively, associated with non-compliance at day 11. End of follow-up echo-Doppler found four cases of asymptomatic distal venous thrombosis. There were no hemorrhagic complications.

DISCUSSION

The risk of thromboembolic complications diminishes over time, while oral anticoagulants have a wide therapeutic window and relatively long half-life (15-17 hrs). Efficacy was demonstrated, with improved patient comfort and cost-saving. Compliance in the present series was satisfactory. This, however, should not mean that patients not be appropriately informed, as in the present study, so as to improve compliance.

LEVEL OF EVIDENCE

Level III, prospective diagnostic.

Dabigatran etexilate: an oral direct thrombin inhibitor for the management of thromboembolic disorders

BACKGROUND

Until recently, warfarin was the only oral anticoagulant available in the United States. Its narrow therapeutic index, interpatient variability in dose response, and drug and food interactions make it difficult to use. Dabigatran etexilate (DE) is a new oral direct thrombin inhibitor that was approved in the US and in Canada for the prevention of thromboembolic events in patients with atrial fibrillation (AF), as well as in Europe and Canada for the prevention of venous thromboembolism (VTE).

OBJECTIVE

To discuss the role of DE for the prevention and treatment of VTE, as well as for the prevention of stroke in patients with AF.

METHODS

Peer-reviewed clinical trials, review articles, and treatment guidelines were identified from MEDLINE and the Current Contents database (both 1966-February 15, 2012) using the search terms dabigatran, VTE, Afib, pharmacokinetics, pharmacodynamics, pharmacoeconomics, and cost-effectiveness. Citations from available articles were also reviewed for additional references.

RESULTS

For VTE prophylaxis, DE 150 or 220 mg orally daily has demonstrated either superiority or noninferiority to subcutaneous enoxaparin once daily in most studies. However, one study failed to demonstrate noninferiority to subcutaneous enoxaparin dosed BID in the composite end point of VTE, and all-cause mortality. For VTE treatment, DE 150 mg BID orally was shown to be noninferior to warfarin in preventing recurrent events. For AF, DE 150 mg BID orally is superior to warfarin in the prevention of thromboembolism, whereas 110 mg BID is noninferior to warfarin. Pharmacoeconomic analyses performed in the United Kingdom and Ireland found that DE can be cost-saving compared with enoxaparin in the prevention of VTE. Adverse effects of DE reported in clinical studies include dyspepsia (12%-13%) and bleeding (minor bleeding: 6%-22%).

CONCLUSIONS

DE exhibited a safety profile and efficacy comparable to enoxaparin for VTE prophylaxis; comparable safety profile and efficacy to warfarin for VTE treatment; and superiority (150 mg BID orally) in the prevention of stroke and systemic embolism compared with warfarin in patients with AF. The relative ease of oral administration, no need for routine monitoring, and lack of significant drug interactions, may favor use of DE over other anticoagulants. However, there is no antidote for DE currently available.

Economic analyses of venous thromboembolism prevention strategies in hospitalized patients: a systematic review

Introduction

Despite evidence-based guidelines for venous thromboembolism prevention, substantial variability is found in practice. Many economic evaluations of new drugs for thromboembolism prevention do not occur prospectively with efficacy studies and are sponsored by the manufacturers, raising the possibility of bias. We performed a systematic review of economic analyses of venous thromboembolism prevention in hospitalized patients to inform clinicians and policy makers about cost-effectiveness and the potential influence of sponsorship.

Methods

We searched MEDLINE, EMBASE, Cochrane Databases, ACP Journal Club, and Database of Abstracts of Reviews of Effects, from 1946 to September 2011. We extracted data on study characteristics, quality, costs, and efficacy.

Results

From 5,180 identified studies, 39 met eligibility and quality criteria. Each addressed pharmacologic prevention: low-molecular-weight heparins versus placebo (five), unfractionated heparin (12), warfarin (eight), one or another agents (five); fondaparinux versus enoxaparin (11); and rivaroxaban and dabigatran versus enoxaparin (two). Low-molecular-weight heparins were most economically attractive among most medical and surgical patients, whereas fondaparinux was favored for orthopedic patients. Fondaparinux was associated with increased bleeding events. Newer agents rivaroxaban and dabigatran may offer additional value. Of all economic evaluations, 64% were supported by manufacturers of a "new" agent. The new agent had a favorable outcome in 38 (97.4%) of 39 evaluations [95% confidence interval [CI] (86.5 to 99.9)]. Among studies supported by a pharmaceutical company, the sponsored medication was economically attractive in 24 (96.0%) of 25 [95% CI, 80.0 to 99.9)]. We could not detect a consistent bias in outcome based on sponsorship; however, only a minority of studies were unsponsored.

Conclusion

Low-molecular-weight heparins and fondaparinux are the most economically attractive drugs for venous thromboembolism prevention in hospitalized patients. Approximately two thirds of evaluations were supported by the manufacturer of the new agent; such drugs were likely to be reported as economically favorable.

Improving prevention and treatment of venous thromboembolism: clinical trial results

BACKGROUND

Venous thromboembolism (VTE) incurs considerable socioeconomic costs, partly owing to the fact that the treatment and prevention of VTE via effective thromboprophylaxis remains suboptimal in the inpatient and outpatient settings of many healthcare systems. A number of organizations-including the National Quality Forum, The Joint Commission, and the Centers for Medicare and Medicaid Services-have established measures to assess and reduce the healthcare burden of VTE. These improvement strategies focus on increasing the use of thromboprophylaxis, implementing existing guidelines, and improving awareness.

FINDINGS

Based on clinical trial results, the oral anti-coagulants rivaroxaban, apixaban, and dabigatran etexilate have been approved in many countries for the prevention of VTE in patients after elective hip or knee replacement surgery. Recently, dabigatran etexilate and rivaroxaban have also been approved in the US for the prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation. In addition, rivaroxaban is currently the only newer anti-coagulant that has been approved in Europe for the treatment of deep vein thrombosis and for the long-term prevention of recurrent VTE. These oral anti-coagulants have several advantages over established anti-coagulants, including no need for routine coagulation monitoring and only minimal food and drug interactions. These characteristics, together with convenient oral administration, may improve adherence and quality of life for patients, which could result in reductions in the rate of VTE.

CONCLUSIONS

These three oral agents have several advantages over established anti-coagulants and could, therefore, address the unmet needs of patients, physicians, and healthcare systems, with the potential to reduce the burden of anti-coagulant management and the occurrence of VTE.

Evaluating the impact of new anticoagulants in the hospital setting

The short-comings of current anticoagulants have led to the development of newer, albeit more expensive, oral alternatives.

OBJECTIVE

To explore the potential impact the new anticoagulants dabigatran and rivaroxaban in the local hospital setting, in terms of utilisation and subsequent costing.

METHOD

A preliminary costing analysis was performed based on a prospective 2-week clinical audit (29th June - 13th July 2009). Data regarding current anticoagulation management were extracted from the medical files of patients admitted to Ryde Hospital. To model potential costing implications of using the newer agents, the reported incidence of VTE/stroke and bleeding events were obtained from key clinical trials.

RESULTS

Data were collected for 67 patients treated with either warfarin (n=46) or enoxaparin (n=21) for prophylaxis of VTE/stroke. At least two-thirds of all patients were deemed suitable candidates for the use of newer oral anticoagulants (by current therapy: warfarin: 65.2% (AF), 34.8% (VTE); enoxaparin: 100%, (VTE)). The use of dabigatran in VTE/stroke prevention was found to be more cost- effective than warfarin and enoxaparin due to significantly lower costs of therapeutic monitoring and reduced administration costs. Rivaroxaban was more cost-effective than warfarin and enoxaparin for VTE/stroke prevention when supplier-rebates (33%) were factored into costing.

CONCLUSION

This study highlights the potential cost- effectiveness of newer anticoagulants, dabigatran and rivaroxaban, compared to warfarin and enoxaparin. These agents may offer economic advantages, as well as clinical benefits, in the hospital-based management of anticoagulated patients.

Pharmacoeconomics of dabigatran etexilate for prevention of thromboembolism after joint replacement surgery

Dabigatran etexilate (DE) is a novel oral anticoagulant indicated for the prevention of venous thromboembolism in patients undergoing total hip or total knee replacement surgery. The majority of these patients receive some kind of thromboprophylaxis, most commonly low-molecular-weight heparin (LMWH). However, the subcutaneous route of LMWH administration may act as a barrier to the continuation of effective anticoagulant prophylaxis after discharge from hospital. The oral route of DE administration may allow more patients to receive extended thromboprophylaxis and may reduce costs, such as those associated with nurse time for LMWH administrations, platelet monitoring, needlestick injuries and sharps disposal. This article presents an overview of the clinical evidence for DE and a systematic review of the economic evaluations of the drug.

Return to theatre following total hip and knee replacement, before and after the introduction of rivaroxaban: a retrospective cohort study

Rivaroxaban has been recommended for routine use as a thromboprophylactic agent in patients undergoing lower-limb arthroplasty. However, trials supporting its use have not fully evaluated the risks of wound complications. This study of 1048 total hip/knee replacements records the rates of return to theatre and infection before and after the change from a low molecular weight heparin (tinzaparin) to rivaroxaban as the agent of chemical thromboprophylaxis in patients undergoing lower-limb arthroplasty. During a period of 13 months, 489 consecutive patients undergoing lower-limb arthroplasty received tinzaparin and the next 559 consecutive patients received rivaroxaban as thromboprophylaxis. Nine patients in the control (tinzaparin) group (1.8%, 95% confidence interval 0.9 to 3.5) returned to theatre with wound complications within 30 days, compared with 22 patients in the rivaroxaban group (3.94%, 95% confidence interval 2.6 to 5.9). This increase was statistically significant (p = 0.046). The proportion of patients who returned to theatre and became infected remained similar (p = 0.10). Our study demonstrates the need for further randomised controlled clinical trials to be conducted to assess the safety and efficacy of rivaroxaban in clinical practice, focusing on the surgical complications as well as the potential prevention of venous thromboembolism.

Dabigatran etexilate: a possible replacement for heparinoids and vitamin K antagonists?

Dabigatran etexilate is the first oral anticoagulant to be approved in the United States in decades. It works directly by inhibiting clot-bound and free factor IIa (ie, thrombin) and indirectly by inhibiting platelet aggregation induced by thrombin. It is approved in the United States for stroke prophylaxis in nonvalvular atrial fibrillation. There is evidence to suggest that it is also effective for the treatment of acute venous thromboembolism and venous thromboembolism prophylaxis after knee and hip replacement surgery. Dabigatran etexilate therapy does not require laboratory monitoring, an advantage over warfarin. Unlike the earlier direct thrombin inhibitor, ximelagatran, it has demonstrated no potential for serious hepatotoxicity. It is also subject to a much lower degree of interpatient variability in dose response, has no diet-drug interactions, and has fewer clinically significant drug-drug interactions compared with warfarin. Dabigatran etexilate appears to be a valuable addition to our anticoagulant armamentarium.

New aspects on treatment modalities for thromboembolic episodes

Venous thromboembolism (VTE) has been treated with a glycosaminoglycan, followed by a vitamin K antagonist during the past 60 years. During the past two decades the glycosaminoglycans have undergone refinement, allowing for simplification of care for these patients, but parenteral administration is still required. Therefore, the current completion of phase III trials with selective, predictable and orally available anticoagulants with rapid onset brings promise for a change in paradigm in the treatment of VTE in the next few years. Whereas these efforts will lead to further simplification of the therapy there are also trials conducted to advance the treatment by rapid resolution of the thromboembolism in order to improve long-term outcome. Catheter-directed thrombolysis, perhaps also with thrombus fragmentation and stent insertion, if demonstrated to be successful for the reduction of the postthrombotic syndrome, will only be an alternative for a minority of patients due to the complexity, risks and cost of therapy. This treatment increases the complexity at the same time as new drug regimens offer simplicity. This review focuses on the novel therapies for VTE although the new anticoagulants will also play a major role in the management of arterial disease, which will be briefly presented.

Dabigatran versus enoxaparin for prevention of venous thromboembolism after hip or knee arthroplasty: a pooled analysis of three trials

BACKGROUND

Three randomized, double-blind trials compared dabigatran, an oral direct thrombin inhibitor, with enoxaparin for the primary prevention of venous thromboembolism (VTE) in patients undergoing elective total hip and knee arthroplasty.

OBJECTIVES AND METHODS

We conducted a pre-specified pooled analysis of these trials. 8,210 patients were randomized, of whom 8,135 were treated (evaluable for safety) with dabigatran 220 mg or 150 mg once-daily, or subcutaneous enoxaparin (40 mg once-daily or 30 mg twice-daily). Efficacy analyses were based on the modified intention-to-treat population of 6,200 patients with an evaluable outcome. The common risk difference (RD) of treatment effect between each dabigatran dose and enoxaparin was estimated using fixed-effects models, and statistical heterogeneity was estimated using the I2 statistic.

RESULTS

The composite outcome of major VTE (proximal deep vein thrombosis and/or pulmonary embolism) and VTE-related mortality occurred in 3.3% of the enoxaparin group versus 3.0% of the dabigatran 220 mg group (RD vs. enoxaparin -0.2%, 95% CI -1.3% to 0.9%, I2=37%) and 3.8% of the 150 mg group (RD vs. enoxaparin 0.5%, -0.6% to 1.6%, I2=0%). Major bleeding occurred in 1.4% of the enoxaparin group versus 1.4% of the dabigatran 220 mg group (RD vs. enoxaparin -0.2%, -0.8% to 0.5%, I2=40%) and 1.1% of the 150 mg group (RD vs. enoxaparin -0.4%, -1.0% to 0.2%, I2=0%).

CONCLUSIONS

Oral dabigatran was as effective as subcutaneous enoxaparin in reducing the risk of major VTE and VTE-related mortality after hip or knee arthroplasty and has a similar bleeding profile.