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

Abstract

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 €1929 lower than aspirin therapy. Continuation of treatment outside the trial period is expected to result in ICERs of below €20,000 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.

Key words::

• Clopidogrel
• Cost-effectiveness
• ST-segment elevation myocardial infarction
• Decision model

Transparency

Declaration of funding

This work was funded by Sanofi-Aventis, the Netherlands.

Declaration of financial/other relationships

S.T. is employed by Pharmerit. Pharmerit received payment from Sanofi Aventis to carry out this research; Pharmerit also carries out consultancy work for several other pharmaceutical companies. B.H. is employed by Pharmerit. F.d.C. is a scientific advisor to Pharmerit. B.v.H. is scientific director and part-owner of Pharmerit and is also has an advisory contract with Sanofi.

Peer reviewers may receive honoraria from CMRO for their review work. Peer Reviewers 1 and 2 have disclosed that they have no relevant financial relationships.

Acknowledgements

We would further like to thank Ron Peters (Department of Cardiology, University Medical Center, Utrecht) for his clinical input and Jenny Berg (i3 Innovus, Stockholm, Sweden) for the use of her model.