Results of an economic model to assess the cost-effectiveness of enoxaparin, a low-molecular-weight heparin, versus warfarin for the prophylaxis of deep vein thrombosis and associated long-term complications in total hip replacement surgery in the United States

Use of Thromboprophylaxis after Autologous Breast Reconstruction: A Cost-Effective Break-Even Analysis

BACKGROUND

Postoperative venous thromboembolism (VTE) is a major source of morbidity and mortality. The use of thromboprophylaxis among surgeons is not well studied in autologous breast reconstruction. The purpose of this study was to determine the rate of VTE in patients with breast cancer undergoing autologous breast reconstruction and to compare the cost-effectiveness of postoperative chemoprophylactic agents.

METHODS

The TriNetX National Health Research Network database was used to identify patients with breast cancer who underwent autologous breast reconstruction surgery between 2002 and 2022. The incidence of VTE within the first 30 days of surgery was calculated. A break-even analysis was performed to determine the break-even rate of VTE at which a chemoprophylactic agent would be cost-effective.

RESULTS

A cohort of 8221 patients was identified in this study. The rate of VTE was significantly higher in those without anticoagulation (4.0%) compared with those who received anticoagulation (2.6%) ( P = 0.0008). The break-even analysis for heparin and enoxaparin cost-effectiveness yielded absolute risk reductions of 0.73% and 1.63% for high-risk patients requiring 30 days of therapy and 0.20% and 0.43% for moderate-risk patients requiring 7 days of therapy, respectively.

CONCLUSIONS

The use of thromboprophylaxis significantly lowered the risk of VTE within 30 days after autologous breast reconstruction. Heparin appeared to be more cost-effective at preventing VTE compared with enoxaparin for both high- and moderate-risk patients. The presented model holds potential for other institution-specific variables that can be easily applied by plastic surgeons to determine the cost-effectiveness of any therapy.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

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.

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.

Oral anticoagulants for primary prevention, treatment and secondary prevention of venous thromboembolic disease, and for prevention of stroke in atrial fibrillation: systematic review, network meta-analysis and cost-effectiveness analysis

BACKGROUND

Warfarin is effective for stroke prevention in atrial fibrillation (AF), but anticoagulation is underused in clinical care. The risk of venous thromboembolic disease during hospitalisation can be reduced by low-molecular-weight heparin (LMWH): warfarin is the most frequently prescribed anticoagulant for treatment and secondary prevention of venous thromboembolism (VTE). Warfarin-related bleeding is a major reason for hospitalisation for adverse drug effects. Warfarin is cheap but therapeutic monitoring increases treatment costs. Novel oral anticoagulants (NOACs) have more rapid onset and offset of action than warfarin, and more predictable dosing requirements.

OBJECTIVE

To determine the best oral anticoagulant/s for prevention of stroke in AF and for primary prevention, treatment and secondary prevention of VTE.

DESIGN

Four systematic reviews, network meta-analyses (NMAs) and cost-effectiveness analyses (CEAs) of randomised controlled trials.

SETTING

Hospital (VTE primary prevention and acute treatment) and primary care/anticoagulation clinics (AF and VTE secondary prevention).

PARTICIPANTS

Patients eligible for anticoagulation with warfarin (stroke prevention in AF, acute treatment or secondary prevention of VTE) or LMWH (primary prevention of VTE).

INTERVENTIONS

NOACs, warfarin and LMWH, together with other interventions (antiplatelet therapy, placebo) evaluated in the evidence network.

MAIN OUTCOME MEASURES

Efficacy Stroke, symptomatic VTE, symptomatic deep-vein thrombosis and symptomatic pulmonary embolism. Safety Major bleeding, clinically relevant bleeding and intracranial haemorrhage. We also considered myocardial infarction and all-cause mortality and evaluated cost-effectiveness.

DATA SOURCES

MEDLINE and PREMEDLINE In-Process & Other Non-Indexed Citations, EMBASE and The Cochrane Library, reference lists of published NMAs and trial registries. We searched MEDLINE and PREMEDLINE In-Process & Other Non-Indexed Citations, EMBASE and The Cochrane Library. The stroke prevention in AF review search was run on the 12 March 2014 and updated on 15 September 2014, and covered the period 2010 to September 2014. The search for the three reviews in VTE was run on the 19 March 2014, updated on 15 September 2014, and covered the period 2008 to September 2014.

REVIEW METHODS

Two reviewers screened search results, extracted and checked data, and assessed risk of bias. For each outcome we conducted standard meta-analysis and NMA. We evaluated cost-effectiveness using discrete-time Markov models.

RESULTS

Apixaban (Eliquis^®, Bristol-Myers Squibb, USA; Pfizer, USA) [5 mg bd (twice daily)] was ranked as among the best interventions for stroke prevention in AF, and had the highest expected net benefit. Edoxaban (Lixiana^®, Daiichi Sankyo, Japan) [60 mg od (once daily)] was ranked second for major bleeding and all-cause mortality. Neither the clinical effectiveness analysis nor the CEA provided strong evidence that NOACs should replace postoperative LMWH in primary prevention of VTE. For acute treatment and secondary prevention of VTE, we found little evidence that NOACs offer an efficacy advantage over warfarin, but the risk of bleeding complications was lower for some NOACs than for warfarin. For a willingness-to-pay threshold of > £5000, apixaban (5 mg bd) had the highest expected net benefit for acute treatment of VTE. Aspirin or no pharmacotherapy were likely to be the most cost-effective interventions for secondary prevention of VTE: our results suggest that it is not cost-effective to prescribe NOACs or warfarin for this indication.

CONCLUSIONS

NOACs have advantages over warfarin in patients with AF, but we found no strong evidence that they should replace warfarin or LMWH in primary prevention, treatment or secondary prevention of VTE.

LIMITATIONS

These relate mainly to shortfalls in the primary data: in particular, there were no head-to-head comparisons between different NOAC drugs.

FUTURE WORK

Calculating the expected value of sample information to clarify whether or not it would be justifiable to fund one or more head-to-head trials.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013005324, CRD42013005331 and CRD42013005330.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

A decision model to estimate a risk threshold for venous thromboembolism prophylaxis in hospitalized medical patients

Essentials Low risk patients don't require venous thromboembolism (VTE) prophylaxis; low risk is unquantified. We used a Markov model to estimate the risk threshold for VTE prophylaxis in medical inpatients. Prophylaxis was cost-effective for an average medical patient with a VTE risk of ≥ 1.0%. VTE prophylaxis can be personalized based on patient risk and age/life expectancy.

SUMMARY

Background Venous thromboembolism (VTE) is a common preventable condition in medical inpatients. Thromboprophylaxis is recommended for inpatients who are not at low risk of VTE, but no specific risk threshold for prophylaxis has been defined. Objective To determine a threshold for prophylaxis based on risk of VTE. Patients/Methods We constructed a decision model with a decision-tree following patients for 3 months after hospitalization, and a lifetime Markov model with 3-month cycles. The model tracked symptomatic deep vein thromboses and pulmonary emboli, bleeding events and heparin-induced thrombocytopenia. Long-term complications included recurrent VTE, post-thrombotic syndrome and pulmonary hypertension. For the base case, we considered medical inpatients aged 66 years, having a life expectancy of 13.5 years, VTE risk of 1.4% and bleeding risk of 2.7%. Patients received enoxaparin 40 mg day-1 for prophylaxis. Results Assuming a willingness-to-pay (WTP) threshold of $100 000/ quality-adjusted life year (QALY), prophylaxis was indicated for an average medical inpatient with a VTE risk of ≥ 1.0% up to 3 months after hospitalization. For the average patient, prophylaxis was not indicated when the bleeding risk was > 8.1%, the patient's age was > 73.4 years or the cost of enoxaparin exceeded $60/dose. If VTE risk was < 0.26% or bleeding risk was > 19%, the risks of prophylaxis outweighed benefits. The prophylaxis threshold was relatively insensitive to low-molecular-weight heparin cost and bleeding risk, but very sensitive to patient age and life expectancy. Conclusions The decision to offer prophylaxis should be personalized based on patient VTE risk, age and life expectancy. At a WTP of $100 000/QALY, prophylaxis is not warranted for most patients with a 3-month VTE risk below 1.0%.

Systematic Review of Safety and Cost-Effectiveness of Venous Thromboembolism Prophylaxis Strategies in Patients Undergoing Craniotomy for Brain Tumor

BACKGROUND

Studies have evaluated various strategies to prevent venous thromboembolism (VTE) in neuro-oncology patients, without consensus.

OBJECTIVE

To perform a systematic review with cost-effectiveness analysis (CEA) of various prophylaxis strategies in tumor patients undergoing craniotomy to determine the safest and most cost-effective prophylaxis regimen.

METHODS

A literature search was conducted for VTE prophylaxis in brain tumor patients. Articles reporting the type of surgery, choice of VTE prophylaxis, and outcomes were included. Safety of prophylaxis strategies was determined by measuring rates of VTE and intracranial hemorrhage. Cost estimates were collected based on institutional data and existing literature. CEA was performed at 30 d after craniotomy, comparing the following strategies: mechanical prophylaxis (MP), low molecular weight heparin with MP (MP+LMWH), and unfractionated heparin with MP (MP+UFH) to prevent symptomatic VTE. All costs were reported in 2016 US dollars.

RESULTS

A total of 34 studies were reviewed (8 studies evaluated LMWH, 12 for MP, and 7 for UFH individually or in combination; 4 studies used LMWH and UFH preoperatively). Overall probability of VTE was 1.49% (95% confidence interval (CI) 0.42-3.72) for MP+UFH, 2.72% [95% CI 1.23-5.15] for MP+LMWH, and 2.59% (95% CI 1.31-4.58) for MP, which were not statistically significant. Compared to a control of MP alone, the number needed to treat for MP+UFH is 91 and 769 for MP+LMWH. The risk of intracranial hemorrhage was 0.26% (95% CI 0.01-1.34) for MP, 0.74% (95% CI 0.09-2.61) for MP+UFH, and 2.72% (95% CI 1.23-5.15) for MP+LMWH, which were also not statistically significant. Compared to MP, the number needed to harm for MP+UFH was 208 and for MP+LMWH was 41. Fifteen studies were included in the final CEA. The estimated cost of treatment was $127.47 for MP, $142.20 for MP+UFH, and $169.40 for MP+LMWH. The average cost per quality-adjusted life-year for different strategies was $284.14 for MP+UFH, $338.39 for MP, and $722.87 for MP+LMWH.

CONCLUSION

Although MP+LMWH is frequently considered the optimal prophylaxis for VTE risk reduction, our model suggests that MP+UFH is the safest and most cost-effective measure to balance VTE and hemorrhage risks in brain tumor patients at lower risk of hemorrhage. MP+LMWH may be more effective for patients at higher risk of VTE.

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.

Current status of cost utility analyses in total joint arthroplasty: a systematic review

BACKGROUND

Total joint arthroplasty (TJA), although considered to be highly beneficial, is associated with substantial costs to the US healthcare system. Cost utility analysis has become an increasingly important means to objectively evaluate the value of a healthcare intervention from the perspective of both extending the quantity and improving the quality of life. Relatively little is known about the overall cost utility analysis evidence base in TJA.

QUESTIONS/PURPOSES

The goals of this review were to (1) determine the cost utility of TJA interventions; (2) critically assess the quality of published US-based cost utility analyses using the Quality of Health Economic Studies instrument; and (3) determine what characteristics were common among studies receiving a high quality score.

METHODS

A systematic review of the literature using the MEDLINE database was performed to compile findings and critically appraise US-based cost utility analysis studies for total hip and knee arthroplasty. Based on review of 676 identified articles, 23 studies were included. We used the Quality of Health Economic Studies instrument to assess study quality and one-sided Fisher's exact tests were applied to analyze the predictors of high-quality cost utility analysis.

RESULTS

Very few studies compare the cost utility of TJA versus nonoperative intervention; however, the available evidence suggests that TJA can be cost-saving and is highly cost-effective compared with conservative management of end-stage arthritis. The majority of identified studies are focused on the cost utility of new implant technologies or comparisons among surgical alternatives. These studies suggest that the upfront costs associated with new technologies are cost-effective when there is a major reduction in a future cost. The quality of identified studies is quite high (Quality of Health Economic Studies Instrument score: mean 86.5; range, 63-100). National funding source (p = 0.095) and lifetime horizon for analysis (p = 0.07) correlate with high-quality evidence but do not reach significance.

CONCLUSIONS

Over the past 15 years, there has been a major increase in the volume of cost utility analyses published in total hip and knee arthroplasty. The quality of cost utility analyses published during that period is good. As increasing attention is paid to value in US health care, more attention should be paid to understanding the cost utility of TJA compared with nonoperative treatment modalities. Future studies may also look to incorporate patient willingness to pay.

The use of warfarin for DVT prophylaxis following hip and knee arthroplasty: how often are patients within their target INR range?

The purpose of this study was to determine the percentage of time that patients are therapeutic when prescribed warfarin for chemical thromboprophylaxis following a hip or knee arthroplasty procedure. One hundred eighty-four patients receiving warfarin for 4weeks postoperatively, dosed using a Web-application accounting for patient demographics, INR levels, and concomitant medication use, were included. Patients with a target INR range between 1.7 and 2.7 were therapeutic for only 54.4% of the time (32.5% subtherapeutic, 13.0% supratherapeutic) while patients with a target INR range between 2.0 and 3.0 were therapeutic for only 45.9% of the time (39.2% subtherapeutic, 14.8% supratherapeutic). Patients receiving warfarin for chemical thromboprophylaxis are within their targeted INR range for only a limited period of time during their postoperative course.

Warfarin for thromboprophylaxis following total joint arthroplasty: are patients safely anti-coagulated?

The purpose of this study was to investigate whether any correlation exists between INR level at discharge and postoperative complications or readmission rates. From 2010-2011, INR levels on discharge, complications and readmissions within 30 days were recorded on 441 patients undergoing joint arthroplasty. Eighty percent (352 of 441) patients had a subtherapeutic INR level at discharge. The overall complication rate was 15% with an 8.6% readmission rate. A supratherapeutic INR level at discharge was associated with both higher readmission rate as well as increased number of complications (P<0.048). Most patients taking warfarin are nontherapeutic at the time of discharge; notably, a supratherapeutic INR places patients at risk for increased complications and readmissions rates following surgery.

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.

Evidence for treatment of muscular vein thrombosis in orthopaedic patients

Background

Does below-knee symptomatic muscular (gastrocnemius or soleus) vein thrombosis (MVT) warrant investigation and treatment in post-operative orthopaedic patients? We performed a literature search and evaluated the evidence looking for guidance regarding this question.

Materials and methods

We performed a literature search with the use of PubMed, Medline and Google Scholar from 1950 to September 2011. Search terms included “muscular vein thrombosis” (MVT) and “isolated gastrocnemius or soleus vein thrombosis” (IGSVT). We reviewed the eight level II studies relevant to our search, only one of which was in a specific orthopaedic population.

Results

Studies looking at the rates of progression of isolated MVT have shown conflicting results. There is also a lack of consensus between studies that compare progression amongst groups with or without anticoagulant treatment. The majority of the studies do not distinguish between medical, surgical or orthopaedic patients.

Conclusions

We cannot confidently recommend commencement of anticoagulation treatment upon identification of MVT in post-operative orthopaedic patients. We can only suggest that, once MVT is diagnosed, the patient should undergo serial ultrasound scan (USS) duplex scans, and if propagation is identified, then treatment may be deemed beneficial.

Level of evidence: III (review of non-randomized controlled cohort/follow-up studies).

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.

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.

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.

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.

Cost and outcomes associated with rivaroxaban vs enoxaparin for the prevention of postsurgical venous thromboembolism from a US payer's perspective

OBJECTIVE

The objective of this analysis was the evaluation of the outcomes and costs associated with rivaroxaban and enoxaparin for the prevention of postsurgical venous thromboembolism (VTE) in patients undergoing total hip replacement (THR) and total knee replacement (TKR) from the US payer perspective.

METHODS

VTE event rates have been reported in three Phase III clinical trials that compared rivaroxaban and enoxaparin for VTE prevention after orthopedic surgery during the prophylaxis (≤35 days for THR patients and 10-14 days for TKR patients) and post-prophylaxis periods (≤90 days following surgery). These data were used in this decision-analytic model to estimate and compare health outcomes and costs associated with rivaroxaban and enoxaparin. The base-case analysis considered the number and costs of symptomatic VTE events during the prophylaxis period only. A 90-day horizon was considered in the sensitivity analysis.

RESULTS

Following THR, when extended durations of prophylaxis (35 days) were compared, rivaroxaban was associated with lower costs than enoxaparin, with total saving costs of $695/patient. When an extended duration of rivaroxaban prophylaxis (35 days) was compared with a short duration (10-14 days) of enoxaparin prophylaxis, rivaroxaban was estimated to prevent 9.9 additional symptomatic VTE events per 1000 patients, while saving $244/patient (rate/1000 patients). In the TKR population, short duration of rivaroxaban prophylaxis was estimated to prevent 13.1 additional symptomatic VTE events per 1000 patients. It was also less costly than short duration enoxaparin prophylaxis, with a saving of $411/patient (rate/1000 patients).

LIMITATIONS

Only statistically significant differences were captured in the base-case economic analysis, and, therefore, differences in pulmonary embolism (PE) and bleeding events were not captured.

CONCLUSIONS

In this model, rivaroxaban reduced total treatment payer costs vs enoxaparin for the prevention of VTE in THR or TKR patients.

Are surgical patients at risk of venous thromboembolism currently meeting the Surgical Care Improvement Project performance measure for appropriate and timely prophylaxis?

The US Surgical Care Improvement Project (SCIP) has approved two performance measures to improve venous thromboembolism (VTE) prevention. SCIP-VTE-2 measures the proportion of surgery patients who received appropriate VTE prophylaxis within 24 h prior to surgery to 24 h after surgery. This study assesses the current rate of achievement of SCIP-VTE-2 criteria using a retrospective data set of real-world surgical patients. The Premier Perspective database, which contains real-world data from >400 US hospitals, was queried (January 2004-December 2006) for in-patient hospital transactional billing records of surgical patients aged >or=18 years. The primary outcome was the proportion of patients achieving SCIP-VTE-2 requirements for appropriate and timely prophylaxis as per the SCIP-VTE-2 algorithm. Of the 149,785 patients included, 56.2% received appropriate prophylaxis and 52.7% achieved the SCIP-VTE-2 performance measure for both appropriate and timely prophylaxis. To conclude, this study highlights that VTE prophylaxis currently only meets SCIP-VTE-2 requirements in approximately half of real-world surgical patients. The use of retrospective analyses such as this hospital billing data analysis may assist hospitals in measuring their current and future performance in VTE prevention.

Cost-effectiveness of guidelines for insertion of inferior vena cava filters in high-risk trauma patients

BACKGROUND

Inferior vena cava filters (IVCFs) can prevent pulmonary embolism (PE); however, indications for use vary. The Eastern Association for the Surgery of Trauma (EAST) 2002 guidelines suggest prophylactic IVCF use in high-risk patients, but the American College of Chest Physicians (ACCP) 2008 guidelines do not. This analysis compares cost-effectiveness of prophylactic vs therapeutic retrievable IVCF placement in high-risk trauma patients.

METHODS

Markov modeling was used to determine incremental cost-effectiveness of these guidelines in dollars per quality-adjusted life-years (QALYs) during hospitalization and long-term follow-up. Our population was 46-year-old trauma patients at high risk for venous thromboembolism (VTE) by EAST criteria to whom either the EAST (prophylactic IVCF) or ACCP (no prophylactic IVCF) guidelines were applied. The analysis assumed the societal perspective over a lifetime. For base case and sensitivity analyses, probabilities and utilities were obtained from published literature and costs calculated from Centers for Medicare & Medicaid Services fee schedules, the Healthcare Cost & Utilization Project database, and Red Book wholesale drug prices for 2007. For data unavailable from the literature, similarities to other populations were used to make assumptions.

RESULTS

In base case analysis, prophylactic IVCFs were more costly ($37,700 vs $37,300) and less effective (by 0.139 QALYs) than therapeutic IVCFs. In sensitivity analysis, the EAST strategy of prophylactic filter placement would become the preferred strategy in individuals never having a filter, with either an annual probability of VTE of ≥ 9.6% (base case, 5.9%), or a very high annual probability of anticoagulation complications of ≥ 24.3% (base case, 2.5%). The EAST strategy would also be favored if the annual probability of venous insufficiency was <7.69% (base case, 13.9%) after filter removal or <1.90% with a retained filter (base case, 14.1%). In initial hospitalization only, EAST guidelines were more costly by $2988 and slightly more effective by .0008 QALY, resulting in an incremental cost-effectiveness ratio of $383,638/QALY.

CONCLUSIONS

Analysis suggests prophylactic IVC filters are not cost-effective in high-risk trauma patients. The magnitude of this result is primarily dependent on probabilities of long-term sequelae (venous thromboembolism, bleeding complications). Even in the initial hospitalization, however, prophylactic IVCF costs for the additional quality-adjusted life years gained did not justify use.

Hospital-based costs associated with venous thromboembolism prophylaxis regimens

Clinically and economically, venous thromboembolic (VTE) disease represents a significant burden to the US healthcare system. This analysis compares the total direct medical costs associated with VTE prophylaxis with enoxaparin and unfractionated heparin (UFH). Hospital discharge and billing records were extracted from the Premier Perspective database (January 2002-December 2006). The primary outcome was the total direct medical costs for discharges that were at risk of VTE and received enoxaparin or UFH. A total of 894,364 discharge records met the study inclusion criteria, of which 39.4% received enoxaparin and 60.6% received UFH. After adjustment for pre-defined covariates, mean total direct medical costs per discharge for the UFH group were $6,443, $1,080 more than those for the enoxaparin group ($5,363; P < .0001). In conclusion, enoxaparin prophylaxis is a cost-saving therapy, when compared with UFH, for the prevention of VTE in patients with a diverse range of medical conditions conferring VTE risk.

Low-molecular-weight heparin versus unfractionated heparin for prophylaxis of venous thromboembolism in medicine patients--a pharmacoeconomic analysis

BACKGROUND

Prevention of in-hospital venous thromboembolism (VTE) is identified internationally as a priority to improve patient safety. Advocated alternatives include low-dose unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH). Although LMWHs are as effective as UFH, less frequent administration and potentially safer adverse effect profile associated with LMWHs might off-set greater drug acquisition costs. The objective of this study was to determine the most cost-effective thromboprophylaxis strategy for hospitalized medicine patients and specific subgroups in Canada.

METHODS

A decision-analytic model assessed costs and outcomes of LMWH compared to UFH for thromboprophylaxis in at-risk hospitalized medicine patients from an institutional perspective. The outcome of interest was the incremental cost-effectiveness ratio (ICER) for preventing deep vein thrombosis (DVT) and combined untoward events (pulmonary embolism [PE], major bleed, and death). The time horizon of the model was the hospital stay.

RESULTS

In the base-case analysis, LMWH thromboprophylaxis resulted in higher costs ($7.40), but 3.6 and 1.1 fewer DVT and untoward events per 1000 patients, respectively, with associated ICERs of $2042 and $6832. Results remained predominantly stable when alternative assumptions were evaluated in the sensitivity analysis. Low-molecular-weight heparin had the most favorable economic profile in patients with a history of DVT. In the probabilistic sensitivity analysis, in 33% of simulations LMWH was less costly and more effective, whereas the reverse was true for UFH only in 13% of simulations.

CONCLUSIONS

Low-molecular-weight heparin administration is a cost-effective alternative for thromboprophylaxis strategy in Canadian hospitalized medicine patients.

Cost effectiveness of venous thromboembolism pharmacological prophylaxis in total hip and knee replacement: a systematic review

Total hip and knee replacements (THR and TKR) are high-risk settings for venous thromboembolism (VTE). This review summarizes the cost effectiveness of VTE prophylaxis regimens for THR and TKR. We searched MEDLINE (January 1997 to October 2009), EMBASE (January 1997 to June 2009) and the UK NHS Economic Evaluation Database (1997 to October 2009). We analysed recent cost-effectiveness studies examining five categories of comparisons: (i) anticoagulants (warfarin, low-molecular-weight heparin [LMWH] or fondaparinux) versus acetylsalicylic acid (aspirin); (ii) LMWH versus warfarin; (iii) fondaparinux versus LMWH; (iv) comparisons with new oral anticoagulants; and (v) extended-duration (> or =3 weeks) versus short-duration (<3 weeks) prophylaxis. We abstracted information on cost and effectiveness for each prophylaxis regimen in order to calculate an incremental cost-effectiveness ratio. Because of variations in effectiveness units reported and horizon length analysed, we calculated two cost-effectiveness ratios, one for the number of symptomatic VTE events avoided at 90 days and the other for QALYs at the 1-year mark or beyond. Our search identified 33 studies with 67 comparisons. After standardization, comparisons between LMWH and warfarin were inconclusive, whereas fondaparinux dominated LMWH in nearly every comparison. The latter results were derived from radiographic VTE rates. Extended-duration prophylaxis after THR was generally cost effective. Small numbers prohibit conclusions about aspirin, new oral anticoagulants or extended-duration prophylaxis after TKR. Fondaparinux after both THR and TKR and extended-duration LMWH after THR appear to be cost-effective prophylaxis regimens. Small numbers for other comparisons and absence of trials reporting symptomatic endpoints prohibit comprehensive conclusions.

The ACCP guidelines for thromboprophylaxis in total hip and knee arthroplasty

The 1986 National Institutes of Health consensus conference Prevention of Venous Thrombosis and Pulmonary Embolism emphasized the high rates of venous thromboembolic disease (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), associated with orthopedic surgery of the lower extremity when performed without thromboprophylaxis. Total joint arthroplasty patients treated with placebo or as controls have, based on studies conducted between 1908 and 2002, a total DVT prevalence of 41% to 85% and a proximal DVT prevalence of 5% to 36% when examined by venography at 7 to 14 days. Prevalence of PE is less certain, but clinical studies have reported a range of 0.9% to 28% for all PE and 0.1% to 2% for fatal PE in control or placebo patients. As the number of total joint arthroplasties in the United States has grown - nearing 1,000,000 annually and expected to increase significantly over the next 20 years as the population ages - so too has interest in appropriate thromboprophylaxis. Methods of preventing VTE are either pharmacologic or mechanical. Guidelines from the American College of Chest Physicians make evidence-based recommendations for both pharmacologic and nonpharmacologic prophylaxis in the settings of total hip and total knee arthroplasty. These recommendations and their underlying rationale are discussed herein.

Incidence and cost burden of post-thrombotic syndrome

Post-thrombotic syndrome (PTS) is a long-term complication of deep-vein thrombosis (DVT), manifesting as swelling, pain, edema, venous ectasia, and skin induration of the affected limb. PTS has been estimated to affect 23-60% of individuals with DVT, frequently occurring within 2 years of the DVT episode. Symptomatic DVT, post-operative asymptomatic DVT, and recurrent DVT are all risk factors for the development of PTS. Treatment of PTS is often ineffective and treatment-related costs represent a healthcare burden. Therefore, prevention of DVT is essential to reduce PTS, and thus improve outcomes and reduce overall healthcare costs. Although recommended by guidelines, appropriate DVT prophylaxis remains considerably underused. This review evaluates the incidence, risk factors, and economic impact of PTS. Increasing the awareness of PTS, and the methods to prevent this complication may help reduce its incidence, improve long-term outcomes in patients, and decrease resulting costs associated with treatment.

An economic evaluation of venous thromboembolism prophylaxis strategies in critically ill trauma patients at risk of bleeding

BACKGROUND

Critically ill trauma patients with severe injuries are at high risk for venous thromboembolism (VTE) and bleeding simultaneously. Currently, the optimal VTE prophylaxis strategy is unknown for trauma patients with a contraindication to pharmacological prophylaxis because of a risk of bleeding.

METHODS AND FINDINGS

Using decision analysis, we estimated the cost effectiveness of three VTE prophylaxis strategies-pneumatic compression devices (PCDs) and expectant management alone, serial Doppler ultrasound (SDU) screening, and prophylactic insertion of a vena cava filter (VCF) -- in trauma patients admitted to an intensive care unit (ICU) with severe injuries who were believed to have a contraindication to pharmacological prophylaxis for up to two weeks because of a risk of major bleeding. Data on the probability of deep vein thrombosis (DVT) and pulmonary embolism (PE), and on the effectiveness of the prophylactic strategies, were taken from observational and randomized controlled studies. The probabilities of in-hospital death, ICU and hospital discharge rates, and resource use were taken from a population-based cohort of trauma patients with severe injuries (injury severity scores >12) admitted to the ICU of a regional trauma centre. The incidence of DVT at 12 weeks was similar for the PCD (14.9%) and SDU (15.0%) strategies, but higher for the VCF (25.7%) strategy. Conversely, the incidence of PE at 12 weeks was highest in the PCD strategy (2.9%), followed by the SDU (1.5%) and VCF (0.3%) strategies. Expected mortality and quality-adjusted life years were nearly identical for all three management strategies. Expected health care costs at 12 weeks were Can$55,831 for the PCD strategy, Can$55,334 for the SDU screening strategy, and Can$57,377 for the VCF strategy, with similar trends noted over a lifetime analysis.

CONCLUSIONS

The attributable mortality due to PE in trauma patients with severe injuries is low relative to other causes of mortality. Prophylactic placement of VCF in patients at high risk of VTE who cannot receive pharmacological prophylaxis is expensive and associated with an increased risk of DVT. Compared to the other strategies, SDU screening was associated with better clinical outcomes and lower costs.

Economic evaluation of dabigatran etexilate for the prevention of venous thromboembolism after total knee and hip replacement surgery

OBJECTIVE

This was an evaluation of the cost-effectiveness of oral dabigatran etexilate compared with subcutaneous low-molecular-weight heparin (enoxaparin) for the prevention of venous thromboembolism (VTE) after total knee replacement (TKR) and total hip replacement (THR) surgery from the perspective of the UK National Health Service.

METHODS

Dabigatran etexilate (220 mg once daily) was compared with enoxaparin (40 mg once daily) in patients undergoing TKR (duration of prophylaxis, 6-10 days) and THR (duration of prophylaxis, 28-35 days). The 10-week acute postsurgical phase was modeled using a decision tree. A Markov process (1-year cycle length) was used to model long-term events (recurrent VTE, postthrombotic syndrome, and consequences of intracranial hemorrhage) for patients' remaining lifetimes. Relative risks for VTE and bleeding events were derived from 2 Phase III studies that compared dabigatran etexilate with enoxaparin 40 mg once daily. The probabilities of long-term events were estimated using data from published longitudinal studies.

RESULTS

Rates of VTE and bleeding events did not differ significantly between dabigatran etexilate and enoxaparin. Dabigatran etexilate was less costly than enoxaparin in TKR and substantially less costly in THR, primarily due to differences in administration costs. The cost of prophylaxis for THR patients, including drugs and administration costs, was estimated at pound 137 for dabigatran etexilate and pound 237 for enoxaparin ( pound 7 for nursing time during the hospital stay, pound 91 for nurse home visits for administration after hospital discharge, and an additional pound 2 in drug costs). At a willingness-to-pay threshold of pound 20,000 per quality-adjusted life-year, the probability of cost-effectiveness for dabigatran etexilate was 75% in TKR and 97% in THR. These results were robust across a range of sensitivity analyses.

CONCLUSION

From the perspective of the UK National Health Service, thromboprophylaxis with dabigatran etexilate was cost-saving compared with enoxaparin 40 mg once daily, with comparable efficacy and safety profiles.

Prevention of venous thromboembolism after surgery

Venous thromboembolism, including deep vein thrombosis and pulmonary embolism, is the third leading cause of cardiovascular death after myocardial infarction and stroke in the United States. Recommendations regarding the type and duration of prophylaxis for the various conditions are summarized herein.

A cost-effectiveness model comparing rivaroxaban and dabigatran etexilate with enoxaparin sodium as thromboprophylaxis after total hip and total knee replacement in the irish healthcare setting

BACKGROUND

It has been estimated that major orthopaedic surgery has the highest risk of venous thromboembolism (deep vein thrombosis and pulmonary embolism) when compared with other surgery. Two new orally active anticoagulants have recently become licensed in Ireland for the primary prevention of venous thromboembolism in adult patients undergoing elective total hip replacement (THR) or total knee replacement (TKR). Rivaroxaban (Xarelto) is a direct factor Xa inhibitor and dabigatran etexilate (Pradaxa) is a prodrug of the active compound dabigatran, which inhibits thrombin.

OBJECTIVE

To evaluate the cost effectiveness of rivaroxaban and dabigatran etexilate compared with enoxaparin sodium for the prophylaxis of venous thromboembolism in patients undergoing elective THR and TKR in the Irish healthcare setting.

METHODS

The evaluation was conducted from the Irish health-payer perspective. A static decision-tree model was developed with a 180-day post-surgery time horizon. Separate models for the disease states THR and TKR were run to accommodate the different venous thromboembolism risks associated with each procedure. Outcome measures were QALYs and life-years gained (LYG). Costs were valued in euro, year 2008 values. One-way sensitivity analysis of all probabilities in the model was performed. A probabilistic sensitivity analysis using second-order Monte Carlo simulation was performed to determine the probability of cost effectiveness at euro 45,000 per QALY threshold.

RESULTS

In the THR base-case model, rivaroxaban dominated both dabigatran etexilate and enoxaparin sodium. The incremental cost-effectiveness ratios for dabigatran etexilate relative to enoxaparin were euro 23,934 per LYG and euro 17,835 per QALY. In the TKR base-case model, rivaroxaban dominated both dabigatran etexilate and enoxaparin sodium. Dabigatran etexilate also dominated enoxaparin sodium. In the one-way sensitivity analysis, the THR model was robust to all but four probability variations; the TKR model was robust to all variations. At a cost-effectiveness threshold of euro 45,000 per QALY, the probability that rivaroxaban was the most cost-effective strategy after THR was 39%, followed by dabigatran etexilate at 32% and enoxaparin sodium at 29%. The probability that rivaroxaban was the most cost-effective strategy after TKR was 46%, followed by dabigatran etexilate at 30% and enoxaparin sodium at 24%.

CONCLUSION

Base-case analysis indicates that when both rivaroxaban and dabigatran etexilate are compared with enoxaparin sodium, rivaroxaban is the less costly and more effective option after THR and TKR. Probabilistic sensitivity analysis indicates that rivaroxaban is the most cost-effective strategy at a cost-effectiveness threshold of euro 45,000 per QALY; however, there is uncertainty regarding this strategy being more cost effective than dabigatran etexilate when both are compared with enoxaparin sodium.

Cost-effectiveness of venous thromboembolism prophylaxis in total hip and knee replacement surgery: the evolving application of health economic modelling over 20 years

OBJECTIVES

In the last two decades, there has been considerable evolution of methods for cost-effectiveness modelling. Some of the first models were developed in the area of venous thromboembolism (VTE) prophylaxis. Hence, this area can serve as an important example to illustrate evolving standards. Our objectives are to document evolving methodology by describing VTE models, assess their critical strengths and weaknesses, and inform future advances for models in this therapeutic area.

RESEARCH DESIGN AND METHODS

A systematic review of economic models of primary VTE prevention following hip and knee replacement surgery was undertaken. Electronic searches of PubMed, EMBASE, the Cochrane library, and grey literature were conducted (1985-2006). Reference lists of included articles and reviews were examined for relevant studies.

RESULTS

Twenty-nine cost-effectiveness models were identified. Nineteen other cost-effectiveness analyses were excluded because they were not model-based; 16 were simple cost calculations and three were analyses of resource use data collected alongside clinical trials. The majority of models (24) were constructed as decision trees, frequently utilising previously published model structures, with some adaptation for new comparators, and/or addition of relevant events omitted by earlier models (e.g., bleeding due to prophylactic treatment). Later models have included Markov processes to model potential long-term consequences of VTE (recurrent VTE and post-thrombotic syndrome) over longer time horizons. Systematic identification of clinical evidence and more sophisticated analysis methods (e.g., Bayesian mixed-treatment comparisons and probabilistic sensitivity analyses) have recently been introduced.

CONCLUSIONS

Model structures have evolved substantially in this highly studied therapeutic area, with improvements made to the model structure, the comprehensiveness of clinical evidence included, and the underlying calculation methodology.

Prevention of venous thromboembolism in the geriatric patient

Elderly patients immobilized because of an acute medical illness or surgery have a very high risk of developing venous thromboembolism (VTE). Aggressive pharmacologic prophylaxis is necessary and should be initiated either at admission for a medical condition or shortly after surgery. Aggressive prophylaxis may result in fewer patients developing VTE in the hospital and ultimately lead to fewer patients requiring full-dose anticoagulation for VTE. Mechanical prophylaxis can be used as an adjunct to an anticoagulant-based regimen but should only be used as primary prophylaxis when there is a contraindication, such as active bleeding. It is recommended that the clinician carefully evaluate the elderly patient's creatinine clearance and weight before prescribing anticoagulants, particularly when using fixed dosing regimens.

The impact of direct-to-consumer advertised drugs on drug sales in the US and New Zealand

Direct-to-consumer advertising (DTCA) of drugs has been suggested to be a factor in the increased burden of healthcare spending within the US. This review article analyses the pharmaceutical spending differences between the US and New Zealand, two nations that allow DTCA. The pharmaceutical spending burden of New Zealand and the US was compared by assessing the impact of heavily advertised drugs and their position and rank in the pharmaceutical spending of their respective nation. The US spends far more money on pharmaceuticals than New Zealand. It may appear that heavily advertised drugs in the US have a potentially larger impact on what is being prescribed and paid for. It is also probable that the differences in healthcare systems in each nation (free market vs socialized medicine) can have an influence on pharmaceutical spending. The great amount of money being spent on pharmaceuticals per capita in the US is a more complex issue than can be solved solely by targeting DTCA.

Cost-effectiveness of Thromboprophylaxis With Intermittent Pneumatic Compression at Cesarean Delivery

OBJECTIVE

To evaluate the cost-effectiveness of thromboprophylaxis at cesarean delivery with intermittent pneumatic compression.

METHODS

A decision tree model using Markov analysis was developed to compare two approaches to perioperative care at the time of cesarean delivery: 1) no use of perioperative thromboprophylaxis and 2) the use of intermittent pneumatic compression for thromboprophylaxis at the time of cesarean delivery. Postcesarean deep venous thrombosis was estimated to occur in 0.7% of patients (75% of whom were asymptomatic), and result in a 9% chance of postthrombotic syndrome. Mechanical prophylaxis was assumed to decrease the risk of deep venous thrombosis by 70% and to cost 120 dollars. Probability of morbidity and mortality of venous thromboembolism as well as anticoagulation and the costs and utilities for different health state were derived from published studies. Sensitivity analysis was performed over a wide range of variable estimates.

RESULTS

Using the assumptions in our base case, routine thromboprophylaxis for cesarean delivery cost 39,545 dollars per quality-adjusted life year. One-way sensitivity analysis revealed that as long as the incidence of postcesarean deep venous thrombosis was at least 0.68%, intermittent pneumatic compression reduced the incidence of deep venous thrombosis by at least 50%, or the cost of intermittent pneumatic compression was less than 180 dollars, the cost-effectiveness of mechanical prophylaxis did not exceed 50,000 dollars per quality-adjusted life year.

CONCLUSION

Mechanical thromboprophylaxis is estimated to be a cost-effective strategy under a wide range of circumstances.

Efficacy of combined modality prophylaxis including short-duration warfarin to prevent venous thromboembolism after total hip arthroplasty

This study reviewed the effectiveness of a trimodality deep venous thrombosis (DVT) prophylactic regimen after primary and revision total hip arthroplasty. Seven hundred five patients were treated with pneumatic compression, adjusted dose warfarin (7 days), and early mobilization. Bilateral lower extremity venous ultrasonography was obtained on postoperative day 3 or 4. The incidence of asymptomatic DVT, symptomatic DVT/pulmonary embolus events within 90 days of surgery, and potential influence of risk factors was retrospectively assessed. Deep venous thrombosis incidence was 4.4% with one (0.1%) nonfatal pulmonary embolus. Increased age, male sex, and DVT history were significant risk factors for thromboembolic events within 90 days of hip arthroplasty. The combination of short-duration warfarin and mechanical prophylaxis with predischarge ultrasound screening was safe and effective in limiting the occurrence of venous thromboembolism.

Pharmacoeconomic considerations in anticoagulant drug use

Anticoagulants are used for the prevention and treatment of venous thromboembolism and for the secondary prevention of stroke and myocardial infarction. The list of available anticoagulants includes unfractionated heparin, low molecular weight heparins, fondaparinux, warfarin and the direct thrombin inhibitors. Numerous randomised controlled trials have pitted one anticoagulant against another to ascertain superiority in terms of safety and efficacy. Differences in these outcomes are assessed using appropriate statistical tests. When a statistically significant difference is found, it is generally accepted that one option is superior to another. There is also an interest in whether there is a clinically significant difference between two or more treatments, even when there may not be a statistically significant difference. This decision is reached through clinical judgment based on logical and ethical considerations. Another important way to judge the difference between alternative treatment strategies is to test for economically significant differences. This is accomplished through pharmacoeconomic analysis. This paper reviews the evidence gathered from published studies designed to detect an economically significant difference between two or more anticoagulants used for the same clinical indication.

Cost-effectiveness of fondaparinux compared with enoxaparin as prophylaxis against venous thromboembolism in patients undergoing hip fracture surgery

OBJECTIVE

To evaluate the cost-effectiveness of fondaparinux relative to enoxaparin as prophylaxis against venous thromboembolism (VTE) in patients undergoing hip fracture surgery.

METHODS

A decision analysis model was created to simulate the impact of fondaparinux 2.5 mg once daily relative to enoxaparin 30 mg twice daily on patient outcomes and costs over various time points up to 5 years after surgery. Probabilities for the analysis were estimated for a hypothetical cohort of 1000 patients undergoing hip fracture surgery in the United States receiving either fondaparinux or enoxaparin according to comparative trial results. Resource use and costs (2003 dollars) were obtained from large health-care databases. Outcome measures were rates of symptomatic VTE events, health-care costs, and incremental cost-effectiveness ratios.

RESULTS

Fondaparinux is estimated to prevent an additional 30 VTE events (per 1000 patients) at 3 months compared with enoxaparin, producing savings of 103 dollars at discharge, 290 dollars over 1 month, 361 dollars over 3 months, and 466 dollars over 5 years. The results remain robust to clinically plausible variation in input parameters and assumptions.

CONCLUSIONS

Fondaparinux improves outcomes and is cost-saving over a broad range of assumptions compared with enoxaparin for prophylaxis of VTE after hip fracture surgery.

Deep vein thrombosis prevention in joint arthroplasties: continuous enhanced circulation therapy vs low molecular weight heparin

Deep vein thrombosis prevention efficacy using a new, miniature, mobile, battery-operated pneumatic system (continuous enhanced circulation therapy [CECT] system) combined with low-dose aspirin was compared to enoxaparin. One hundred twenty-one patients who underwent total hip or knee arthroplasty were prospectively randomized into 2 groups. The study group was treated by the CECT system starting immediately after the induction of anesthesia. Postoperatively, a daily 100-mg aspirin tablet was added. The control group received 40 mg of enoxaparin per day. Bilateral venography was performed at the fifth to eight postoperative day. In the CECT group, as compared to the enoxaparin group, there was a significantly lower overall rate of DVT and proximal DVT. Safety profiles were similar in both groups. The combination of the CECT device with low-dose aspirin is more effective than enoxaparin in preventing deep-vein thrombosis after lower limb arthroplasties.

Prevention of Venous Thromboembolism in the Geriatric Patient

Elderly patients immobilized because of an acute medical illness or surgery have a very high risk of developing venous thromboembolism (VTE). Aggressive pharmacologic prophylaxis is necessary and should be initiated either at admission for a medical condition or shortly after surgery. Aggressive prophylaxis may result in fewer patients developing VTE in the hospital and ultimately lead to fewer patients requiring full-dose anticoagulation for VTE. Mechanical prophylaxis can be used as an adjunct to an anticoagulant-based regimen but should only be used as primary prophylaxis when there is a contraindication, such as active bleeding. It is recommended that the clinician carefully evaluate the elderly patient's creatinine clearance and weight before prescribing anticoagulants, particularly when using fixed dosing regimens.

Dalteparin versus warfarin for the prevention of recurrent venous thromboembolic events in cancer patients: a pharmacoeconomic analysis

OBJECTIVE

In a recent randomised trial (CLOT [Comparison of Low molecular weight heparin versus Oral anticoagulant Therapy for long term anticoagulation in cancer patients with venous thromboembolism]), which evaluated secondary prophylaxis of venous thromboembolism (VTE) in cancer patients, dalteparin reduced the relative risk of recurrent VTEs by 52% compared with oral anticoagulation therapy (p = 0.002). A Canadian pharmacoeconomic analysis was conducted to measure the economic value of dalteparin for this indication.

DESIGN

The study was conducted from the Canadian healthcare system. The first part of this study utilised the CLOT trial database, from which resource utilisation data were converted into Canadian cost estimates (Can dollars, year 2005 values). Univariate and multivariate regression analyses were conducted to compare the total cost of therapy between patients randomised to treatment with dalteparin or oral therapy. Health state utilities and treatment preferences were then measured in 24 oncology care providers using the time trade-off technique.

RESULTS

When all of the cost components were combined for the entire population (n = 676), patients in the dalteparin group had significantly higher overall costs than the control group (Can dollars 4162 vs Can dollars 2003; p < 0.001). The preference assessment revealed that 23 of 24 respondents (96%) selected dalteparin over warfarin, with an associated gain of 0.157 QALYs. When the incremental cost of dalteparin (Can dollars 2159 per patient) was combined with the QALY gain, the findings revealed that dalteparin was associated with a cost of approximately Can dollars 13,800 (95% CI 12,400, 15,100) per QALY gained.

CONCLUSIONS

Given the practical advantages of dalteparin in terms of convenience, improved efficacy and the acceptable economic value, this analysis suggests that long-term dalteparin therapy is a sound alternative to warfarin for the prevention of recurrent VTEs in patients with cancer.

A systematic review of economic analyses of low-molecular-weight heparin for the treatment of venous thromboembolism

INTRODUCTION

Public concerns about the increase in health care expenditure have prompted investigators to analyze the costs and benefits of health care interventions. We conducted a systematic review of economic analyses of venous thromboembolism treatment focusing on studies evaluating low-molecular-weight heparin.

MATERIALS AND METHODS

We identified studies by a MEDLINE search and a review of bibliographies of retrieved articles. From each eligible study, we extracted data on the study characteristics, the effectiveness, and the cost of managing the venous thromboembolism with respect to treatment. We critically appraised the studies according to the framework from the Users' Guides to the Medical Literature XIII: How to Use an Article on Economic Analysis of Clinical Practice.

RESULTS

Six of these eight economic analyses of venous thromboembolism treatment that met the inclusion criteria for this review showed that low-molecular-weight heparin is associated with less recurrent venous thromboembolism and is less costly than treatment with unfractionated heparin. Although discrete recurrent venous thromboembolism event rates were not included in the seventh study, these investigators concluded that the cost of low-molecular-weight heparin for the treatment of venous thromboembolism treatment was offset by the savings associated with fewer hospital admissions when low-molecular-weight heparin was used. In the eighth study, although the cost of treatment with low-molecular-weight heparin was higher than treatment with unfractionated heparin, the investigators concluded that low-molecular-weight heparin is cost-effective for inpatient management.

CONCLUSIONS

Low-molecular-weight heparin treatment may confer economic advantages over unfractionated heparin therapy because it does not require anticoagulant monitoring and it facilitates outpatient therapy.

A cost-effectiveness analysis of fondaparinux sodium compared with enoxaparin sodium as prophylaxis against venous thromboembolism: use in patients undergoing major orthopaedic surgery

OBJECTIVE

To determine the cost effectiveness of fondaparinux sodium compared with enoxaparin sodium for prophylaxis against venous thromboembolism in patients undergoing major orthopaedic surgery.

METHODS

Using a cohort simulation model, two primary analyses were conducted from the perspective of the US healthcare payer. Probabilities for a trial-based analysis were obtained from patients participating in the fondaparinux clinical trial programme supplemented with data from published literature. Probabilities for a label-based analysis were estimated for a hypothetical cohort of US patients receiving either fondaparinux or enoxaparin as recommended by US FDA-approved labelling. Resource use and costs were obtained from large US healthcare databases. Outcome measures were rates of symptomatic thromboembolic events and healthcare costs. Costs were in 2003 values.

RESULTS

In the trial-based analysis, fondaparinux was estimated to prevent 15.1 symptomatic venous thromboembolic events (per 1,000 patients) at 3 months for patients undergoing major orthopaedic surgery compared with enoxaparin. The cost savings (per patient) of using fondaparinux over enoxaparin are US 61 dollars at 30 days, US 89 dollars at 3 months, and US 155 dollars at 5 years. In the label-based analysis, fondaparinux was estimated to prevent 17.8 venous thromboembolic events (per 1,000 patients) at 3 months compared with enoxaparin, producing savings per patient of US 25 dollars at discharge, US 112 dollars over 1 month, US 141 dollars over 3 months and US 234 dollars over 5 years. Results remain robust to clinically plausible variation in input parameters and assumptions.

CONCLUSION

Our model suggests that fondaparinux, when compared with the current standard regimen of enoxaparin for prophylaxis of venous thromboembolism in major orthopaedic surgery, improves outcomes and is cost saving from a US healthcare-payer perspective over the broad range of assumptions evaluated.