Oral antiplatelet therapy in secondary prevention of cardiovascular events: an assessment from the payer's perspective

Early-stage health technology assessment of fractional flow reserve coronary computed tomography versus standard diagnostics in patients with stable chest pain in The Netherlands

OBJECTIVES

The aim of this early-stage Health Technology Assessment (HTA) was to assess the difference in healthcare costs and effects of fractional flow reserve derived from coronary computed tomography (FFRct) compared to standard diagnostics in patients with stable chest pain in The Netherlands.

METHODS

A decision-tree model was developed to assess the difference in total costs from the hospital perspective, probability of correct diagnoses, and risk of major adverse cardiovascular events at one year follow-up. One-way sensitivity analyses were conducted to determine the main drivers of the cost difference between the strategies. A threshold analysis on the added price of FFRct analysis (computational analysis only) was conducted.

RESULTS

The mean one-year costs were €2,680 per patient for FFRct and €2,915 per patient for standard diagnostics. The one-year probability of correct diagnoses was 0.78 and 0.61, and the probability of major adverse cardiovascular events was 1.92x10-5 and 0.01, respectively. The probability and costs of revascularization and the specificity of coronary computed tomography angiography had the greatest effect on the difference in costs between the strategies. The added price of FFRct analysis should be below €935 per patient to be considered the least costly option.

CONCLUSIONS

The early-stage HTA findings suggest that FFRct may reduce total healthcare spending, probability of incorrect diagnoses, and major adverse cardiovascular events compared to current diagnostics for patients with stable chest pain in the Dutch healthcare setting over one year. Future cost-effectiveness studies should determine a value-based pricing for FFRct and quantify the economic value of the anticipated therapeutic impact.

Health economic evaluation of rivaroxaban in the treatment of patients with chronic coronary artery disease or peripheral artery disease

Aims

In the COMPASS trial, rivaroxaban 2.5 mg twice daily (bid) plus acetylsalicylic acid (ASA) 100 mg once daily (od) performed better than ASA 100 mg od alone in reducing the rate of cardiovascular disease, stroke, or myocardial infarction (MI) in patients with coronary artery disease (CAD) and peripheral artery disease (PAD). A Markov model was developed to assess the cost-effectiveness of rivaroxaban plus ASA vs. ASA alone over a lifetime horizon, from the UK National Health System perspective.

Methods and results

The base case analysis assumed that patients entered the model in the event-free health state, with the possibility to experience ≤2 events, transitioning every three-month cycle, through acute and post-acute health states of MI, ischaemic stroke (IS), or intracranial haemorrhage (ICH), and death. Costs, quality-adjusted life-years (QALYs), life years—all discounted at 3.5%—and incremental cost-effectiveness ratios (ICERs) were calculated. Deterministic and probabilistic sensitivity analyses were conducted, as well as scenario analyses. In the model, patients on rivaroxaban plus ASA lived for an average of 14.0 years with no IS/MI/ICH, and gained 9.7 QALYs at a cost of £13 947, while those receiving ASA alone lived for an average of 12.7 years and gained 9.3 QALYs at a cost of £8126. The ICER was £16 360 per QALY. This treatment was cost-effective in 98% of 5000 iterations at a willingness-to-pay threshold of £30 000 per QALY.

Conclusion

This Markov model suggests that rivaroxaban 2.5 mg bid plus ASA is a cost-effective alternative to ASA alone in patients with chronic CAD or PAD.

Cost-effectiveness of rivaroxaban and aspirin compared to aspirin alone in patients with stable cardiovascular disease: An Australian perspective

OBJECTIVE

In light of the Cardiovascular Outcomes for People using Anticoagulation Strategies (COMPASS) trial, our objective was to assess the cost-effectiveness, from the Australian healthcare perspective, of rivaroxaban in combination with aspirin versus aspirin alone for the prevention of recurrent cardiovascular disease among patients with stable atherosclerotic vascular disease.

METHODS

A Markov model was developed using input data from the COMPASS trial to predict the clinical course and costs of patients over a 20-year time-horizon. The model comprised of three health states: 'Alive without recurrent CVD', 'Alive after recurrent CVD' and 'Dead'. Costs were from the Australian public healthcare system perspective, and estimated from published sources, as were utility data. The costs of rivaroxaban were based on current acquisition prices on the Australian Pharmaceutical Benefits Schedule (PBS) and assumed as AUD$3.09/day. The main outcome of interest was the incremental cost-effectiveness ratio (ICER) in terms of cost per quality adjusted life year (QALY) gained, and cost per year of life saved (YoLS). Costs and benefits were discounted by 5.0% per year.

RESULTS

Compared to aspirin alone, rivaroxaban plus aspirin was estimated to cost an additional AUD$12,156 (discounted) per person, but lead to 0.516 YoLS (discounted) and 0.386 QALYs gained (discounted), over 20 years. These equated to ICERs of AUD$23,560/YoLS and AUD$31,436/QALY gained. We have assumed a threshold of AUD$50,000/QALY gained to signify cost-effectiveness.

CONCLUSION

Compared to aspirin, rivaroxaban in combination with aspirin is likely to be cost-effective in preventing recurrent cardiovascular events in patients with stable atherosclerotic vascular disease.

Rivaroxaban for Preventing Atherothrombotic Events in People with Acute Coronary Syndrome and Elevated Cardiac Biomarkers: An Evidence Review Group Perspective of a NICE Single Technology Appraisal

As part of its Single Technology Appraisal process, the National Institute for Health and Care Excellence (NICE) invited the company that manufactures rivaroxaban (Xarelto, Bayer) to submit evidence of the clinical and cost effectiveness of rivaroxaban for the prevention of adverse outcomes in patients after the acute management of acute coronary syndrome (ACS). The School of Health and Related Research Technology Appraisal Group at the University of Sheffield was commissioned to act as the independent Evidence Review Group (ERG). The ERG produced a critical review of the evidence for the clinical and cost effectiveness of the technology, based upon the company's submission to NICE. The evidence was derived mainly from a randomised, double-blind, phase III, placebo-controlled trial of rivaroxaban (either 2.5 or 5 mg twice daily) in patients with recent ACS [unstable angina, non-ST segment elevation myocardial infarction (NSTEMI) or ST segment elevation myocardial infarction (STEMI)]. In addition, all patients received antiplatelet therapy [aspirin alone or aspirin and a thienopyridine either as clopidogrel (approximately 99 %) or ticlopidine (approximately 1 %) according to national or local guidelines]. The higher dose of rivaroxaban (5 mg twice daily) did not form part of the marketing authorisation. A post hoc subgroup analysis of the licensed patients who had ACS with elevated cardiac biomarkers (that is, patients with STEMI and NSTEMI) without prior stroke or transient ischaemic stroke showed that compared with standard care, the addition of rivaroxaban (2.5 mg twice daily) to existing antiplatelet therapy reduced the composite endpoint of cardiovascular mortality, myocardial infarction or stroke, but increased the risk of major bleeding and intracranial haemorrhage. However, there were a number of limitations in the evidence base that warrant caution in its interpretation. In particular, the evidence may be confounded because of the post hoc subgroup analysis, modified intention-to-treat analyses, high dropout rates and missing vital status data. Results from the company's economic evaluation showed that the deterministic incremental cost-effectiveness ratio (ICER) for rivaroxaban in combination with aspirin plus clopidogrel or with aspirin alone compared with aspirin plus clopidogrel or aspirin alone was £6203 per quality-adjusted life-year (QALY) gained. In contrast, the ERG's preferred base case estimate was £5622 per QALY gained. The ICER did not rise above £10,000 per QALY gained in any of the sensitivity analyses undertaken by the ERG, although the inflexibility of the company's economic model precluded the ERG from formally undertaking all desired exploratory analyses. As such, only a crude exploration of the impact of additional bleeding events could be undertaken. The NICE Appraisal Committee concluded that the ICERs presented were all within the range that could be considered cost effective and that the results of the ERG's exploratory sensitivity and scenario analyses suggested that the ICER was unlikely to increase to the extent that it would become unacceptable. The Appraisal Committee therefore concluded that rivaroxaban in combination with aspirin plus clopidogrel, or with aspirin alone, was a cost-effective use of National Health Service (NHS) resources for preventing atherothrombotic events in people with ACS and elevated cardiac biomarkers.

Cost-effectiveness Analysis of Rivaroxaban in the Secondary Prevention of Acute Coronary Syndromes in Sweden

BACKGROUND

Worldwide, coronary heart disease accounts for 7 million deaths each year. In Sweden, acute coronary syndrome (ACS) is a leading cause of hospitalization and is responsible for 1 in 4 deaths.

OBJECTIVE

The aim of this analysis was to assess the cost-effectiveness of rivaroxaban 2.5 mg twice daily (BID) in combination with standard antiplatelet therapy (ST-APT) versus ST-APT alone, for the secondary prevention of ACS in adult patients with elevated cardiac biomarkers without a prior history of stroke/transient ischemic attack (TIA), from a Swedish societal perspective, based on clinical data from the global ATLAS ACS 2-TIMI 51 trial, literature-based quality of life data and costs sourced from Swedish national databases.

METHODS

A Markov model was developed to capture rates of single and multiple myocardial infarction (MI), ischemic and hemorrhagic stroke, thrombolysis in myocardial infarction (TIMI) major, minor, and "requiring medical attention" bleeds, revascularization events, and associated costs and utilities in patients who were stabilized after an initial ACS event. Efficacy and safety data for the first 2 years came from the ATLAS ACS 2-TIMI 51 trial. Long-term probabilities were extrapolated using safety and effectiveness of acetylsalicylic acid data, which was estimated from published literature, assuming constant rates in time. Future cost and effects were discounted at 3.0%. Univariate and probabilistic sensitivity analyses were conducted.

RESULTS

In the base case, the use of rivaroxaban 2.5 mg BID was associated with improvements in survival and quality-adjusted life years (QALYs), yielding an incremental cost per QALY of 71,246 Swedish Krona (SEK) (€8045). The outcomes were robust to changes in inputs. The probabilistic sensitivity analysis demonstrated rivaroxaban 2.5 mg BID to be cost-effective in >99.9% of cases, assuming a willingness-to-pay threshold of SEK 500,000 (€56,458).

CONCLUSION

Compared with ST-APT alone, the use of rivaroxaban 2.5 mg BID in combination with ST-APT can be considered a cost-effective treatment option for ACS patients with elevated cardiac biomarkers without a prior history of stroke/TIA in Sweden.

FUNDING

Bayer Pharma AG.

Cost-effectiveness and public health benefit of secondary cardiovascular disease prevention from improved adherence using a polypill in the UK

OBJECTIVE

To evaluate the public health and economic benefits of adherence to a fixed-dose combination polypill for the secondary prevention of cardiovascular (CV) events in adults with a history of myocardial infarction (MI) in the UK.

DESIGN

Markov-model-based cost-effectiveness analysis, informed by systematic reviews, which identified efficacy, utilities and adherence data inputs.

SETTING

General practice in the UK.

PARTICIPANTS

Patients with a mean age of 64.7 years, most of whom are men with a recent or non-recent diagnosis of MI and for whom secondary preventive medication is indicated and well tolerated.

INTERVENTION

Fixed-dose combination polypill (100 mg aspirin, 20 mg atorvastatin and 2.5, 5, or 10 mg ramipril) compared with multiple monotherapy.

PRIMARY AND SECONDARY OUTCOME MEASURES

CV events prevented per 1000 patients; cost per life-year gained; and cost per quality-adjusted life-year (QALY) gained.

RESULTS

The model estimates that for each 10% increase in adherence, an additional 6.7% fatal and non-fatal CV events can be prevented. In the base case, over 10 years, the polypill would improve adherence by ∼20% and thereby prevent 47 of 323 (15%) fatal and non-fatal CV events per 1000 patients compared with multiple monotherapy, with an incremental cost-effectiveness ratio (ICER) of £8200 per QALY gained. Probabilistic sensitivity analyses for the base-case assumptions showed an 81.5% chance of the polypill being cost-effective at a willingness-to-pay threshold of £20,000 per QALY gained compared with multiple monotherapy. In scenario analyses that varied structural assumptions, ICERs ranged between cost saving and £21,430 per QALY gained.

CONCLUSIONS

Assuming that some 450,000 adults are at risk of MI, a 10 percentage point uptake of the polypill could prevent 3260 CV events and 590 CV deaths over a decade.The polypill appears to be a cost-effective strategy to prevent fatal and non-fatal CV events in the UK.

Assessing uncertainties surrounding combined endpoints for use in economic models

BACKGROUND

To increase power to detect a treatment effect, trials may combine multiple endpoints such as survival, myocardial infarctions, and strokes. When such trials are used to define the uncertainty associated with input parameters in an economic model, the output uncertainty will depend on the way in which the dependency between individual endpoints is modeled.

OBJECTIVE

To develop a flexible approach to model the interrelationship between individual components of a combined endpoint.

METHODS

A standard independent Dirichlet approach is compared with a dependent Dirichlet approach and logistic approaches. The logistic approaches use a link between the various endpoints by either an observed clinical variable (cholesterol) or a latent one. The logistic and Dirichlet methods are compared using 6 statin trials including 5 endpoints: myocardial infarction (MI), stroke, fatal MI, fatal stroke, and other cardiovascular death. The results are compared using the point estimates and uncertainty in a simplified cardiovascular model to calculate point estimates and uncertainty of estimated incremental life-years when applying probabilistic sensitivity analysis. The influence of the link between endpoints is tested by changing the prior in the logistic approaches.

RESULTS

The dependent Dirichlet approach reduces uncertainty up to 29% and changes the point estimate by up to 28%. The logistic approach with uninformative priors does not affect the uncertainty and point estimates. When strong priors are used, the uncertainty margins get smaller (up to 49%) and point estimates vary more. Including information about cholesterol has limited impact.

CONCLUSIONS

The logistic approaches offer a flexible way to reflect one's beliefs about the interrelationships between individual endpoints, potentially decreasing uncertainty margins. The approach works equally well with and without data concerning the underlying disease process.

Cost-effectiveness of 12-month treatment with ticagrelor compared with clopidogrel in the management of acute coronary syndromes

BACKGROUND

The PLATO (Platelet Inhibition and Patient Outcomes) randomized trial (NCT00391872) in patients with acute coronary syndromes (ACS) reported that ticagrelor (in addition to aspirin) reduced the rate of the composite end point of myocardial infarction (MI), stroke, or cardiovascular death compared with clopidogrel (in addition to aspirin) by 16% over 12 months (P < 0.001). No significant difference in the incidence of major bleeding was noted, but ticagrelor was associated with a higher rate of major bleeding not related to coronary artery bypass grafting.

OBJECTIVE

By extrapolating the key findings of PLATO, we sought to assess the cost-effectiveness of ticagrelor compared with clopidogrel in the management of ACS in a contemporary Australian setting.

METHODS

A Markov model with 4 health states (free from further ACS events, MI, stroke, and death) was developed to simulate the long-term costs and outcomes associated with ACS. Event risks were based on data derived directly from PLATO, and costs and utilities were drawn from published sources. A 10-year time horizon was simulated, and future costs and benefits were discounted at a 5% annual rate. However, treatment with ticagrelor and clopidogrel was only assumed for the first 12 months, with no benefits applied beyond drug cessation. Sensitivity analyses were undertaken based on variations to key data inputs. All costs for resource use applied in the analysis were based on published Australian prices (in 2010/2011 dollars [A$]).

RESULTS

Over 10 years, the estimated quality-adjusted life-years lived per-patient were 5.74 and 5.68 for ticagrelor and clopidogrel, respectively. Net costs were A$19,132 for ticagrelor and A$18,428 for clopidogrel. These equated to an incremental cost-effectiveness ratio of A$9031 per quality-adjusted life-year gained for ticagrelor compared with clopidogrel. Sensitivity analyses indicated the result to be robust.

CONCLUSIONS

When assessed from the perspective of the Australian health care system, ticagrelor is likely to be cost-effective compared with clopidogrel in preventing downstream morbidity and mortality associated with ACS.

Ticagrelor versus genotype-driven antiplatelet therapy for secondary prevention after acute coronary syndrome: a cost-effectiveness analysis

BACKGROUND

Clopidogrel's effectiveness is likely reduced significantly for prevention of thrombotic events after acute coronary syndrome (ACS) in patients exhibiting a decreased ability to metabolize clopidogrel into its active form. A genetic mutation responsible for this reduced effectiveness is detectable by genotyping. Ticagrelor is not dependent on gene-based metabolic activation and demonstrated greater clinical efficacy than clopidogrel in a recent secondary prevention trial. In 2011, clopidogrel will lose its patent protection and likely will be substantially less expensive than ticagrelor.

OBJECTIVE

To determine the cost-effectiveness of ticagrelor compared with a genotype-driven selection of antiplatelet agents.

METHODS

A hybrid decision tree/Markov model was used to estimate the 5-year medical costs (in 2009 US$) and outcomes for a cohort of ACS patients enrolled in Medicare receiving either genotype-driven or ticagrelor-only treatment. Outcomes included life years and quality-adjusted life years (QALYs) gained. Data comparing the clinical performance of ticagrelor and clopidogrel were derived from the Platelet Inhibition and Patient Outcomes trial.

RESULTS

The incremental cost-effectiveness ratio (ICER) for universal ticagrelor was $10,059 per QALY compared to genotype-driven treatment, and was most sensitive to the price of ticagrelor and the hazard ratio for death for ticagrelor compared with clopidogrel. The ICER remained below $50,000 per QALY until a monthly ticagrelor price of $693 or a 0.93 hazard ratio for death for ticagrelor relative to clopidogrel. In probabilistic analyses, universal ticagrelor was below $50,000 per QALY in 97.7% of simulations.

CONCLUSION

Prescribing ticagrelor universally increases quality-adjusted life years for ACS patients at a cost below a typically accepted threshold.

Costs and consequences of clopidogrel versus aspirin for secondary prevention of ischaemic events in (high-risk) atherosclerotic patients in Sweden: a lifetime model based on the CAPRIE trial and high-risk CAPRIE subpopulations

BACKGROUND

Antiplatelet therapy plays a central role in the prevention of atherothrombotic events. Both acetylsalicylic acid (aspirin) and clopidogrel have been shown to reduce the risk of recurrent cardiovascular events in various subgroups of patients with vascular disease.

OBJECTIVE

To estimate the cost effectiveness of clopidogrel versus aspirin in Sweden for the prevention of atherothrombotic events based on CAPRIE trial data. The focus of this study is on two high-risk subpopulations: (i) patients with pre-existing symptomatic atherosclerotic disease; and (ii) patients with polyvascular disease.

METHODS

A Markov model combining clinical, epidemiological and cost data was used to assess the economic value of clopidogrel compared with aspirin during a patient's lifetime. A societal perspective was used, with costs stated in Swedish kronor (SEK), year 2007 values. For the first 2 years, the clinical input for the model was based on the relevant subpopulations in the CAPRIE trial. Thereafter, transition probabilities were extrapolated, taking account of increased risks related to age and to a history of events. Cost effectiveness of 2 years of therapy is presented as cost per life-year gained (LYG) and as cost per QALY. Univariate and multivariate sensitivity analyses were performed to investigate robustness of results.

RESULTS

For patients resembling the total CAPRIE population, who were treated with clopidogrel, the expected cost per LYG was SEK217,806 and the cost per QALY was estimated at SEK169,154. For the high-risk CAPRIE subpopulations, costs per QALY were lowest for patients with pre-existing symptomatic atherosclerotic disease (SEK38,153). Using a 'willingness-to-pay' perspective indicated that treatment with clopidogrel instead of aspirin in high-risk patients is associated with a high probability for cost effectiveness; 81% using a threshold of SEK100,000 per QALY and 98% using a threshold of SEK500,000 per QALY. Overall, the results appeared to be robust over the sensitivity analyses performed.

CONCLUSION

When considering the cost-effectiveness categorization as proposed by the Swedish National Board of Health and Welfare, clopidogrel appears to be associated with costs per QALY that range from intermediate in the total CAPRIE population to low in high-risk atherosclerotic patients.

Clopidogrel in the management of acute coronary syndromes: indications, results, obstacles

Atherothrombosis is the underlying pathology of the acute coronary syndromes (ACS), in which platelet activation plays a key role. Therefore, antiplatelet therapy is an essential component of guideline-recommended ACS management. Considerable evidence clearly demonstrates the benefits of the antiplatelet agent clopidogrel in reducing mortality, decreasing recurrent cardiovascular events, and increasing arterial patency in ACS patients. Despite this evidence, data from patient registries and clinical initiatives such as CRUSADE (Can Rapid stratification of Unstable angina Suppress ADverse outcomes with Early implementation of the American College of Cardiology/American Heart Association guidelines) and GRACE (Global Registry of Acute Coronary Events) indicate that clopidogrel is underused in patients with ACS. This is especially true for patients receiving conservative medical management, many of whom have significant risk for recurrent ischemic events. The purpose of this review is to compare "real-life" clopidogrel therapy with evidence-based guidelines, and to highlight clinical factors that drive clopidogrel implementation or provide barriers to its use in ACS patients.

Cost-effectiveness of clopidogrel: seeing through the smoke

BACKGROUND

The authors reviewed various recommendations and practices for cost-effectiveness analysis. They also performed a PubMed search for clopidogrel and cost-effectiveness from 2004 to early 2008 to obtain original analyses published in English to look for possible associations of assumptions and conclusions with reported pharmaceutical support.

RESULTS

. Inclusion of incident cases and truncation at a sensible follow-up time more appropriately reflect the burden to be assumed by third-party payers. Extending the time horizon too far runs the risk of decreasing any relation with future reality. Parsimony cannot justify simplifications that omit relevant issues such as noncoronary costs, which worsen the calculated cost-effectiveness ratio of clopidogrel by 5% to 27%. The choice of the population to be analyzed has a major effect on cost-effectiveness: pharmaceutically sponsored studies published between 2004 and early 2008 focused on high-risk patients and have routinely shown more favorable cost-effectiveness ratios for clopidogrel than studies without pharmaceutical support.

CONCLUSION

. Any entity hoping to make the cost-effectiveness ratio of clopidogrel look more favorable would prefer the isolated, cohort approach and limit the analysis to high-risk patients most likely to benefit from it. This approach ignores the reality of medical policies and does not address the most relevant questions regarding the optimum use of clopidogrel.