Long-term clopidogrel therapy in patients receiving percutaneous coronary intervention

Cost-Effectiveness of Coronary and Peripheral Artery Disease Antithrombotic Treatments in Finland

Introduction

Currently, 15–20% of individuals with coronary artery disease (chronic coronary syndrome [CCS]) or peripheral artery disease (PAD) receiving routine treatment experience cardiovascular events (CVEs) within 3–4 years. Using PICOSTEPS (Patients-Intervention-Comparators-Outcomes-Setting-Time-Effects-Perspective-Sensitivity analysis) reporting, we evaluated the cost-effectiveness of recently approved rivaroxaban 2.5 mg twice daily in combination with acetylsalicylic acid 100 mg daily (RIV + ASA) for the prevention of CVEs among Finns with CCS or symptomatic PAD.

Methods

Myocardial infarction, ischemic stroke, intracranial hemorrhage, acute limb ischemia, amputations, major extracranial bleeding, venous thromboembolism, and cardiovascular deaths were modeled in a Markov model examining a cohort of patients with CCS or symptomatic PAD. Relative effects of the intervention (RIV + ASA) and comparator (ASA) were based on the COMPASS trial. The primary outcome was 3%/year discounted incremental cost-effectiveness ratio (ICER), defined as cost (2019 euros) per quality-adjusted life year (QALY) gained in the Finnish setting over a lifetime horizon. In addition to nonfatal and fatal CVEs, the effects factored Finnish non-CVE mortality, quality of life, and direct costs from a public payer perspective. Disaggregated costs and QALYs, costs per life year gained (LYG), and ischemic strokes avoided, net monetary benefit (NMB), expected value of perfect information (EVPI), economic value-added (EVA), cost-effectiveness table, and acceptability frontier were examined. Probabilistic and deterministic sensitivity analyses were conducted.

Results

In the deterministic comparison with ASA over a lifetime horizon, RIV + ASA resulted in a benefit of 0.404 QALYs and 0.474 LYGs for an additional cost of €3241, resulting in an ICER of €8031/QALY. The probabilistic ICER was €4313/QALY (EVPI €1829/patient). RIV + ASA had positive NMB (€8791/patient), low EVPI (€88/patient), high EVA (€8703/patient), and 91% probability of cost-effectiveness using the willingness-to-pay of €25,254/QALY. The primary result was conservative and robust for RIV + ASA.

Conclusion

RIV + ASA was a cost-effective treatment alternative compared with ASA in patients with CCS or symptomatic PAD in Finland.

Electronic supplementary material

The online version of this article (10.1007/s12325-020-01398-8) contains supplementary material, which is available to authorized users.

Finland lacks published evidence on the cost-effectiveness of approved interventions for the prevention of cardiovascular events among individuals with chronic coronary syndrome (stable coronary artery disease) or symptomatic peripheral artery disease at risk of cardiovascular complications. Rivaroxaban 2.5 mg twice daily plus acetylsalicylic acid 100 mg once daily is indicated and reimbursed in Finland for the prevention of cardiovascular events for patients with stable coronary artery disease or symptomatic peripheral artery disease. We assessed the effectiveness and costs of treatment with rivaroxaban plus acetylsalicylic acid in comparison with treatment with acetylsalicylic acid. That is, we examined whether rivaroxaban is cost-effective when prescribed in combination with acetylsalicylic acid.

Cardiovascular events with their associated costs and impact on quality of life were modeled over the lifetime of patients. The main effectiveness outcome was quality-adjusted life years (modeled survival multiplied by the expected quality of life), and costs included those relevant to the Finnish public payer in 2019. Extensive sensitivity analyses were carried out to evaluate the impacts of different model inputs and rationale.

Rivaroxaban plus acetylsalicylic acid had high probability of being cost-effective, compared with acetylsalicylic acid. By valuing quality-of-life benefit with a plausible willingness-to-pay, net cost savings of €8791 per patient could be gained or economic value added by €8703 per patient if rivaroxaban was used.

Cost-effective analysis of clopidogrel versus aspirin for high risk patients with established peripheral arterial disease in China

Objective: To assess the cost-effectiveness of clopidogrel versus aspirin for high risk patients (pre-existing symptomatic atherosclerosis or multi-vascular territory involvement) with established peripheral arterial disease (PAD) for secondary prevention of atherothrombotic events in a Chinese setting.Methods: A Markov model with a lifetime horizon was developed from the perspective of the national healthcare system in China. The primary outputs are quality adjusted life years (QALYs), direct medical costs, and the incremental cost-effectiveness ratios (ICERs). Clinical efficacy data were obtained from the CAPRIE trial. Drug acquisition cost, other direct medical costs, and utilities were from pricing records and the literature. One-way sensitivity analysis and probabilistic sensitivity analysis (PSA) were conducted to test the robustness of the model on all parameters.Results: In patients with pre-existing atherosclerosis, 2 years of treatment with clopidogrel and aspirin would yield total QALYs of 8.776 and 8.576 at associated costs of ¥18,777 ($2,838) and ¥12,302 ($1,859), respectively, resulting in an ICER of ¥32,382 ($4,893) per QALY gained. In patients with PVD, secondary prevention with the same drugs would expect to lead to total QALYs of 8.836 and 8.632 at associated costs of ¥18,518 ($2,798) and ¥12,041 ($1,820), respectively, resulting in a corresponding ICER of ¥31,743 ($4,797) per QALY gained. The results were most sensitive to the discount rate for future outcomes and costs. The PSA indicated that the probability of clopidogrel being cost-effective was 100% at the willingness-to-pay threshold of 3-times GDP.Conclusions: Secondary prevention with clopidogrel is an attractive cost-effective option compared with aspirin for high risk patients with established PAD from the perspective of the national healthcare system in Chinese settings.

Costs of clinical events in type 2 diabetes mellitus patients in the Netherlands: A systematic review

BACKGROUND

Type 2 diabetes mellitus (T2DM) is an established risk factor for cardiovascular and nephropathic events. In the Netherlands, prevalence of T2DM is expected to be as high as 8% by 2025. This will result in significant clinical and economic impact, highlighting the need for well-informed reimbursement decisions for new treatments. However, availability and consistent use of costing methodologies is limited.

OBJECTIVE

We aimed to systematically review recent costing data for T2DM-related cardiovascular and nephropathic events in the Netherlands.

METHODS

A systematic literature review in PubMed and Embase was conducted to identify available Dutch cost data for T2DM-related events, published in the last decade. Information extracted included costs, source, study population, and costing perspective. Finally, papers were evaluated using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS).

RESULTS

Out of initially 570 papers, 36 agreed with the inclusion criteria. From these studies, 150 cost estimates for T2DM-related clinical events were identified. In total, 29 cost estimates were reported for myocardial infarction (range: €196-€27,038), 61 for stroke (€495-€54,678), fifteen for heart failure (€325-€16,561), 24 for renal failure (€2,438-€91,503), and seventeen for revascularisation (€3,000-€37,071). Only four estimates for transient ischaemic attack were available, ranging from €587 to €2,470. Adherence to CHEERS was generally high.

CONCLUSIONS

The most expensive clinical events were related to renal failure, while TIA was the least expensive event. Generally, there was substantial variation in reported cost estimates for T2DM-related events. Costing of clinical events should be improved and preferably standardised, as accurate and consistent results in economic models are desired.

Chinese Herbal Medicines Might Improve the Long-Term Clinical Outcomes in Patients with Acute Coronary Syndrome after Percutaneous Coronary Intervention: Results of a Decision-Analytic Markov Model

Aims. The priority of Chinese herbal medicines (CHMs) plus conventional treatment over conventional treatment alone for acute coronary syndrome (ACS) after percutaneous coronary intervention (PCI) was documented in the 5C trial (chictr.org number: ChiCTR-TRC-07000021). The study was designed to evaluate the 10-year effectiveness of CHMs plus conventional treatment versus conventional treatment alone with decision-analytic model for ACS after PCI. Methods and Results. We constructed a decision-analytic Markov model to compare additional CHMs for 6 months plus conventional treatment versus conventional treatment alone for ACS patients after PCI. Sources of data came from 5C trial and published reports. Outcomes were expressed in terms of quality-adjusted life years (QALYs). Sensitivity analyses were performed to test the robustness of the model. The model predicted that over the 10-year horizon the survival probability was 77.49% in patients with CHMs plus conventional treatment versus 77.29% in patients with conventional treatment alone. In combination with conventional treatment, 6-month CHMs might be associated with a gained 0.20% survival probability and 0.111 accumulated QALYs, respectively. Conclusions. The model suggested that treatment with CHMs, as an adjunctive therapy, in combination with conventional treatment for 6 months might improve the long-term clinical outcome in ACS patients after PCI.

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.

Model performance evaluation (validation and calibration) in model-based studies of therapeutic interventions for cardiovascular diseases : a review and suggested reporting framework

Decision analytic models play an increasingly important role in the economic evaluation of health technologies. Given uncertainties around the assumptions used to develop such models, several guidelines have been published to identify and assess 'best practice' in the model development process, including general modelling approach (e.g., time horizon), model structure, input data and model performance evaluation. This paper focuses on model performance evaluation. In the absence of a sufficient level of detail around model performance evaluation, concerns regarding the accuracy of model outputs, and hence the credibility of such models, are frequently raised. Following presentation of its components, a review of the application and reporting of model performance evaluation is presented. Taking cardiovascular disease as an illustrative example, the review investigates the use of face validity, internal validity, external validity, and cross model validity. As a part of the performance evaluation process, model calibration is also discussed and its use in applied studies investigated. The review found that the application and reporting of model performance evaluation across 81 studies of treatment for cardiovascular disease was variable. Cross-model validation was reported in 55 % of the reviewed studies, though the level of detail provided varied considerably. We found that very few studies documented other types of validity, and only 6 % of the reviewed articles reported a calibration process. Considering the above findings, we propose a comprehensive model performance evaluation framework (checklist), informed by a review of best-practice guidelines. This framework provides a basis for more accurate and consistent documentation of model performance evaluation. This will improve the peer review process and the comparability of modelling studies. Recognising the fundamental role of decision analytic models in informing public funding decisions, the proposed framework should usefully inform guidelines for preparing submissions to reimbursement bodies.

Cost-effectiveness of atazanavir/ritonavir compared with lopinavir/ritonavir in treatment-naïve human immunodeficiency virus-1 patients in Sweden

OBJECTIVE

The aim of this study was to estimate the cost-effectiveness of atazanavir/ritonavir (atazanavir/r) versus lopinavir/ritonavir (lopinavir/r) in treatment-naïve human immunodeficiency virus-1 (HIV-1) patients in Sweden for whom efavirenz is not suitable.

METHODS

A Markov model was developed to predict the lifetime outcomes of atazanavir/r and lopinavir/r in terms of quality-adjusted life years (QALYs) and total costs. The model was structured to focus on treatment lines--how patients progress from first- to second-, and then to third-line treatment. Model inputs were derived directly from clinical trials, such as the CASTLE study (a 96-week head-to-head trial in first-line therapy), and from the Framingham risk-equation. The analysis was conducted from a payer perspective and included extensive scenario and probabilistic sensitivity analyses.

RESULTS

The model predicted atazanavir/r to save 0.16 (95% confidence interval (CI) 0.00 to 0.33) QALYs and reduce total costs by -202,896 SEK (95% CI -332,156 to -81,644 SEK) over a lifetime horizon. Probabilistic sensitivity analyses showed that atazanavir/r had a 100% probability to be cost-effective at a willingness to pay of 200,000 SEK per QALY.

CONCLUSION

The results indicate that atazanavir/r is cost-saving and more effective compared to lopinavir/r for patients who have previously not been exposed to antiretroviral drugs in Sweden.

Clinical bioequivalence of a dose of clopidogrel Leti Cravid tablets 75 mg versus clopidogrel Sanofi Plavix tablets 75 mg administered on a daily dose for 7 days on healthy volunteers: a clinical trial

Patients undergoing percutaneous coronary intervention procedures, as in patients with coronary disease, should receive treatment indefinitely with acetylsalicylic acid and clopidogrel. New brands of clopidogrel have been developed at lower costs, for helping to avoid premature suspension of antiplatelet therapy, as Cravid Leti Laboratories clopidogrel. Its effectiveness and safety must be compared with Plavix international standard. A prospective, comparative, cross-over, and randomized study was conducted in healthy volunteers. Each group received 1 tablet of Clopidogrel Leti or Clopidogrel Sanofi, 75 mg in a single dose daily for 7 days, followed by 7-day washout period before administration of second treatment. Platelet aggregation was measured at the start of each period and at 7 days of treatment through optical aggregometry, using an optical aggregometer 490-2D Chrono-Log, with a self-calibration system working with platelet-rich plasma with readings 0%-100% of light transmission. An important decrease of platelet aggregation was observed in both groups at 7 days of treatment of more than 50%, independent of adenosine diphosphate reactive (Helena and Chrono-Log) used for aggregation (P < 0.05). The relationship between the mean and 90% confidence interval ratio obtained with the 2 different adenosine diphosphate brands were between 80% and 125%, therefore, it can be considered that both brands are bioequivalent and perfectly exchangeable.

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.

Adherence to guidelines for sensitivity analysis: cost-effectiveness analyses of dual oral antiplatelet therapy

OBJECTIVE

Cost-effectiveness analyses of new treatments for cardiovascular disease frequently require input parameters whose values are known with uncertainty due to limited data. The objective of this paper is to examine the extent to which published sensitivity analyses addressing this uncertainty adhere to Health Technology Assessment (HTA) guidelines.

RESEARCH DESIGN AND METHODS

A systematic review of published cost-effectiveness analyses was performed for an example drug treatment scenario, dual oral antiplatelet therapy compared with aspirin alone following acute coronary syndromes and/or percutaneous coronary intervention. The following medical literature databases were searched for articles published from January 1997 to June 2007: PubMed, Cochrane Collaboration, EMBASE and the Health Economic Evaluation Database (HEED). Evidence tables were created to show the sensitivity of the cost-effectiveness estimates to changes in the input parameter values, as well as the data sources used for the reference-case and sensitivity analysis input parameter values. The extent to which the sensitivity analyses adhered to HTA guidelines were also examined.

RESULTS

Cost-effectiveness ratios were most sensitive to changes in the efficacy of dual antiplatelet therapy and reference-case model assumptions about costs beyond the trial period. Although alternative values tested in the sensitivity analysis for some input parameters were based on observed ranges or distributions, alternative values tested for many other input parameters were assumed without justification.

CONCLUSIONS

Sensitivity analyses in the cost-effectiveness studies of dual oral antiplatelet therapy were not fully adherent with HTA guidelines. In particular, long-term costs and benefits were not always included in the sensitivity estimates, the impact of differential effects on death and myocardial infarction was not explored, and justification for the alternative parameter values tested was not always provided.

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.

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

BACKGROUND

A wide variety of oral antiplatelet trials have been carried out, and a large number of cost-effectiveness estimates based on them have been published.

OBJECTIVE

To assess the cost effectiveness of oral antiplatelet treatments in the prevention of cardiovascular events.

METHODS

A comprehensive literature search was carried out in PubMed and the Cochrane Library and the data reviewed. Cost-effectiveness or cost-utility studies of oral antiplatelets published since 2000 were selected. Cost-effectiveness analyses from the perspective of the UK NHS were then carried out using a Markov model with a 6-month cycle length and a lifetime horizon. Inputs from the CAPRIE, CHARISMA, (PCI)-CURE, CREDO, COMMIT, CLARITY, ESPS 2 and ESPRIT trials were included. All estimates of cost found (per event avoided, per QALY gained or per life-year gained) were included. Results were analysed in light of the National Institute for Health and Clinical Excellence (NICE) guidelines for the use of antiplatelets for the prevention of cardiovascular events and all estimates were updated to pound (year 2006 values) for easy comparison.

RESULTS

Of the initial 141 studies found, 21 were included in the initial review. The literature and the Markov model subsequently used suggest that aspirin (acetylsalicylic acid) dominates placebo for the secondary prevention of cardiovascular events, as it is effective, is also less costly and is as well tolerated as placebo. Additionally, in periods or patients with elevated risk, more intensive treatment with clopidogrel (alone or together with aspirin) is cost effective compared with aspirin alone for the secondary prevention of ischaemic events. For secondary stroke prevention, combination therapy with aspirin and dipyridamole has a favourable incremental cost-effectiveness ratio (ICER) when compared with aspirin alone and, based on an indirect comparison, also when compared with clopidogrel.

CONCLUSIONS

The cost-effectiveness estimates presented in this article support the NICE guidelines for the use of antiplatelets for the prevention of cardiovascular events. Based on these pharmacoeconomic data alone, aspirin should be prescribed for primary or secondary prevention among patients at high risk of cardiovascular events, dipyridamole for the secondary prevention of stroke (for a maximum of 5 years), and clopidogrel for the treatment of symptomatic cardiovascular disease or acute coronary syndrome (for a maximum of 2 years). The cost effectiveness of antiplatelets hinges on the patient's initial risk, the risk reduction associated with treatment, and the price of the treatment. Evidence suggests that the cost effectiveness of antiplatelets can be optimized by individualising the treatment decision based on patient risk and expected risk reduction.