Cost-effectiveness of clopidogrel treatment in percutaneous coronary intervention: a European model based on a meta-analysis of the PCI-CURE, CREDO and PCI-CLARITY trials

Impact of Double Loading Regimen of Clopidogrel on Final Angiographic Results, Incidence of Upper Gastrointestinal Bleeding and Clinical Outcomes in Patients with STEMI Undergoing Primary Coronary Intervention

This study tested the therapeutic impact of double-loading dose (i.e., 600 mg) versus standard-loading dose (i.e., 300 mg) of clopidogrel on ST-segment-elevation-myocardial-infarction (STEMI) patients undergoing primary-coronary-intervention (PCI).Between January 2005 and December 2013, a total of 1461 STEMI patients undergoing PCI were consecutively enrolled into the study and categorized into group 1 (600 mg/clopidogrel; n = 508) and group 2 (300 mg/clopidogrel; n = 953). We assessed angiographic thrombolysis-in-myocardial-infarction (TIMI) flow in the infarct-related-artery, 30-day mortality and upper-gastrointestinal-bleeding (UGIB) within 30 days as primary-endpoints and later incidents of UGIB as secondary-endpoints.The results showed that the incidences of advanced Killip score (defined as ≥ score 3) upon presentation (23.8% versus 24.6%) and advanced heart failure (defined as ≥ NYHAFc-3) (10.2% versus 10.4%) did not differ between groups 1 and 2 (all P > 0.4). Primary-endpoints, which were final TIM-3 flow (91.3% versus 91.7%) in the infarct-related-artery, incidences of 30-day mortality (5.8% vs. 7.1%), and UGIB ≤ 30 day (7.8% versus 8.9%) did not differ between group 1 and group 2 (all P > 0.33). The secondary-endpoints which were incidences of ≥ 30-day < one-year (5.2% versus 4.7) and > one-year (8.9% versus 10.1%) UGIB did not differ between groups 1 and 2 (all P > 0.45). One-year mortality did not differ between two groups (10.74% versus 12.9%) (P > 0.25). Multiple-stepwise-logistic-regression analysis showed that age and advanced-Killip score were independently predictive of 30-day mortality (all P < 0.001).Double-loading dose of clopidogrel did not confer an additional benefit to the final angiograph results, 30-day/one-year clinical outcomes; and age and advanced Killip-score were powerful predictors of 30-day mortality.

A systematic review of the quality of economic models comparing thrombosis inhibitors in patients with acute coronary syndrome undergoing percutaneous coronary intervention

BACKGROUND

Thrombosis inhibitors can be used to treat acute coronary syndromes (ACS). However, there are various alternative treatment strategies, of which some have been compared using health economic decision models.

OBJECTIVE

To assess the quality of health economic decision models comparing thrombosis inhibitors in patients with ACS undergoing percutaneous coronary intervention, and to identify areas for quality improvement.

DATA SOURCES

The literature databases MEDLINE, EMBASE, EconLit, National Health Service Economic Evaluation Database (NHS EED), Database of Abstracts of Reviews of Effects (DARE) and Health Technology Assessment (HTA).

STUDY APPRAISAL AND SYNTHESIS METHODS

A review of the quality of health economic decision models was conducted by two independent reviewers, using the Philips checklist.

RESULTS

Twenty-one relevant studies were identified. Differences were apparent regarding the model type (six decision trees, four Markov models, eight combinations, three undefined models), the model structure (types of events, Markov states) and the incorporation of data (efficacy, cost and utility data). Critical issues were the absence of particular events (e.g. thrombocytopenia, stroke) and questionable usage of utility values within some studies.

LIMITATIONS

As we restricted our search to health economic decision models comparing thrombosis inhibitors, interesting aspects related to the quality of studies of adjacent medical areas that compared stents or procedures could have been missed.

CONCLUSIONS

This review identified areas where recommendations are indicated regarding the quality of future ACS decision models. For example, all critical events and relevant treatment options should be included. Models also need to allow for changing event probabilities to correctly reflect ACS and to incorporate appropriate, age-specific utility values and decrements when conducting cost-utility analyses.

Antiplatelet therapy in patients undergoing percutaneous coronary intervention: economic considerations

Percutaneous coronary intervention (PCI) is one of the most common medical procedures performed for treatment of coronary artery disease. Antiplatelet medications as adjunctive therapy for PCI are used routinely, with indications for specific agents or their combinations varying depending on the clinical scenario. While the cost-effectiveness of well-established agents has been extensively studied, newer drugs have not been evaluated as thoroughly. In addition, the clinical application of some antiplatelet drugs has recently changed, thus making older studies of cost effectiveness less applicable to the current landscape of clinical practice. This article reviews cost-effectiveness considerations of antiplatelet therapies in the treatment of coronary artery disease in patients undergoing PCI. Aspirin, P2Y12 inhibitors including clopidogrel and the newer agents prasugrel and ticagrelor, as well as glycoprotein (GP) IIb/IIIa inhibitors, are discussed. Overall, the use of dual antiplatelet therapy with aspirin and a P2Y12 inhibitor in patients undergoing PCI improves ischaemic outcomes and appears to be cost effective. The few available studies suggest that the recently approved medications prasugrel and ticagrelor are cost-effective alternatives to clopidogrel. However, no direct comparison between these two newer agents is available. The indications for GP IIb/IIIa inhibitors have changed in the current PCI era, and there is a paucity of cost-effectiveness data for their use in contemporary care.

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.

P2Y12 receptor: platelet thrombus formation and medical interventions

Platelets express a wide range of receptors and proteins that play essential roles in thrombus formation. Among these, the P2Y(12) receptor, a member of the G protein-coupled receptor family, has attracted a significant amount of attention. Stimulation of the P2Y(12) receptor by ADP results in activation of various signaling pathways involved in amplification of platelet activation and aggregation. There have been extensive attempts to design an ideal antithrombotic agent to block P2Y(12), which shows selective expression, as an intervention for cardiovascular disease. Current inhibitors of the P2Y(12) receptor include indirect inhibitor members of the thienopyridine family (ticlopidine, clopidogrel, and prasugrel), and direct P2Y(12) inhibitors (ticagrelor, cangrelor and elinogrel). Of these, clopidogrel is the most commonly prescribed P2Y(12) blocker; however, this product does not fulfill the ideal therapeutic requirements. The main limitations of clopidogrel administration include slow onset, prevention of recovery of platelet functions, and interindividual variability. Hence, advanced studies have been carried out to achieve more efficient and safer P2Y(12) blockade. In this review, we provide a brief but comprehensive report on P2Y(12), its role on platelet thrombus formation, and the targeting of this receptor as an intervention for cardiovascular disease, for the benefit of basic science and clinical researchers.

Clopidogrel versus aspirin in patients with atherothrombosis: a CAPRIE-based cost-effectiveness model for Greece

BACKGROUND

Atherothrombosis represents a leading cause of morbidity and mortality worldwide. Given the prominent role of platelet aggregation in atherothrombosis, antiplatelet therapy forms the cornerstone of treatment, with proven efficacy in the secondary prevention of atherothrombotic events. Although clopidogrel seems to be superior to aspirin in terms of risk reduction for an atherothrombotic event, whether this clinical advantage is cost effective in Greece is unknown.

OBJECTIVE

The aim of this study was to conduct a cost-effectiveness analysis comparing clopidogrel with aspirin in the secondary prevention of atherothrombotic events in patients with peripheral artery disease, a recent stroke or a recent myocardial infarction, from the third-party-payer perspective in Greece.

METHODS

A Markov model with a 6-month cycle length was developed. Transition probabilities used in the model were obtained from the event rates reported in the CAPRIE trial. The effect of clopidogrel was applied only during the first 2 years of the model. Utility data were used to estimate quality-adjusted life-years (QALYs). Costs (for the year 2012) assigned to each health state included antiplatelet treatment cost, cost for the management of adverse events related to antiplatelet therapy and the direct healthcare cost of patients (i.e. concomitant medication, hospitalization, outpatient visits, rehabilitation, laboratory and imaging diagnostic examinations as well as interventions) in the acute and follow-up phase, separately. The incremental cost-effectiveness ratio (ICER) was calculated for life-years (LYs) and QALYs, separately. A probabilistic sensitivity analysis was conducted in order to evaluate the impact of the variation that characterizes the majority of model parameters to the cost-effectiveness results.

RESULTS

The Markov analysis revealed that the discounted survival was 11.83 (95% CI 11.40, 12.22) years and 12.17 (95% CI 11.75, 12.55) years in the aspirin and clopidogrel treatment groups, respectively, a difference of 0.34 (95% CI 0.09, 0.618) LYs. The corresponding discounted QALYs were 8.63 (95% CI 8.34, 8.90) and 8.84 (95% CI 8.54, 9.10), respectively, a difference of 0.21 (95% CI 0.05, 0.37) QALYs. The cumulated lifetime costs per patient were €20 678 (95% CI 19 675, 21 724) and €21 688 (95% CI 20 649, 22 773), for aspirin and clopidogrel treatment arm, respectively. The ICER for clopidogrel was calculated to be €4038 (95% CI 2743, 7837) for each LY saved and €5518 (95% CI 3358, 12 921) for each QALY saved.

CONCLUSION

The analysis indicates that clopidogrel is cost effective for the secondary prevention of atherothrombotic events in the Greek setting. These findings are in line with those reported in other European countries.

Cost of clinical events in health economic evaluations in Germany: a systematic review

Guidance from the Institute for Quality and Efficiency in Health Care (IQWiG) on cost estimation in cost-benefit assessments in Germany acknowledges the need for standardization of costing methodology. The objective of this review was to assess current methods for deriving clinical event costs in German economic evaluations. A systematic literature search of 24 databases (including MEDLINE, BIOSIS, the Cochrane Library and Embase) identified articles, published between January 2005 and October 2009, which reported cost-effectiveness or cost-utility analyses. Studies assessed German patients and evaluated at least one of 11 predefined clinical events relevant to patients with diabetes mellitus. A total of 21 articles, describing 199 clinical cost events, met the inclusion criteria. Year of costing and time horizon were available for 194 (97%) and 163 (82%) cost events, respectively. Cost components were rarely specified (32 [16%]). Costs were generally based on a single literature source (140 [70%]); where multiple sources were cited (32 [16%]), data synthesis methodology was not reported. Cost ranges for common events, assessed using a Markov model with a cycle length of 12 months, were: acute myocardial infarction (nine studies), first year, 4,618-17,556 €; follow-up years, 1,006-3,647 €; and stroke (10 studies), first year; 10,149-24,936 €; follow-up years, 676-7,337 €. These results demonstrate that costs for individual clinical events vary substantially in German health economic evaluations, and that there is a lack of transparency and consistency in the methods used to derive them. The validity and comparability of economic evaluations would be improved by guidance on standardizing costing methodology for individual clinical events.

Recurrent acute stent thrombosis due to allergic reaction secondary to clopidogrel therapy

Despite significant benefits including mortality advantage demonstrated with antiplatelet therapy in large clinical trials, the occurrence of adverse ischemic events, including stent thrombosis after percutaneous coronary intervention has been the challenging and devastating complication. Clopidogrel as a monotherapy, or more common in combination with aspirin, represents a cornerstone of modern pharmacotherapy in the invasive era. Although vigilance in maintenance of this dual antiplatelet treatment is mandatory, obligatory cessation of one of these agents can be observed in rare circumstances of adverse events. We describe a patient who developed recurrent acute stent thrombosis associated with clopidogrel-induced allergic reaction and discuss our therapeutic considerations.

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.

Cost-effectiveness of clopidogrel in STEMI patients in the Netherlands: a model based on the CLARITY trial

OBJECTIVE

This study assesses the costs and effects of combination treatment with clopidogrel and aspirin in comparison to aspirin alone in patients with an ST-segment elevation myocardial infarction (STEMI) in a Dutch setting.

METHODS

A decision tree model is used to combine data from different sources about efficacy, epidemiology and costs. In the short-run, cost-effectiveness is based on efficacy data derived from the CLARITY trial. The cost-effectiveness of continued treatment is addressed by analysing which conditions need to be fulfilled to deem the strategy 'cost-effective', and discussing whether it is likely that it is. Estimates concerning the benefits of preventing events are derived from Swedish registries. Approximations of both direct and indirect costs are derived from the literature. Effects are expressed as life years gained and Quality Adjust Life Years (QALYs). Uncertainties are addressed by uni- and multivariate sensitivity analyses with and without taking account of the dependency between the separate ischaemic events.

RESULTS

A treatment regimen similar to that of the CLARITY trial, including patients similar to those in the trial, is estimated to result in 0.05 additional life years and 0.062 additional quality adjusted life years for a cost that is euro1929 lower than aspirin therapy. Continuation of treatment outside the trial period is expected to result in ICERs of below euro20,000 per QALY as long as the real risk reduction of combination treatment is greater than 0.487% per year.

CONCLUSION

The results indicate that clopidogrel therapy combined with aspirin, according to the regimen seen in CLARITY, and using data from Swedish registries to inform the model, is cost-effective. Sensitivity analyses suggest that the model is robust to a wide range of parameter estimates, including those based on data from Swedish registries. Continued treatment is very likely to be cost effective in light of all the indirect evidence.

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.