CLOPIDOGREL AND DIPYRIDAMOLE FOR PREVENTION OF VASCULAR EVENTS

Clinical effectiveness and cost- effectiveness of clopidogrel and modified-release (MR) dipyridamole for the secondary prevention of occlusive vascular events

Background

The importance of long-term secondary prevention in patients at high risk of recurrent vascular events is clear and aspirin and other oral antiplatelet agents have been shown to be protective in such patients. This review examined the clinical effectiveness and cost-effectiveness of two alternative antiplatelet agents, clopidogrel and modified-release dipyridamole, relative to prophylactic doses of aspirin for the secondary prevention of occlusive vascular events.

Findings

Clopidogrel was marginally more effective than aspirin at reducing the risk of ischaemic stroke, MI or vascular death in patients with atherosclerotic vascular disease, however, it did not reduce the risk of vascular death or death from any cause compared with aspirin. There was no statistically significant difference in the number of bleeding complications experienced in the clopidogrel and aspirin groups. MR-dipyridamole in combination with aspirin was superior to aspirin alone at reducing the risk of stroke and marginally more effective at reducing the risk of stroke and/or death. Compared with treatment with MR-dipyridamole alone, MR-dipyridamole in combination with aspirin significantly reduced the risk of stroke. Treatment with MR-dipyridamole in combination with aspirin did not statistically significantly reduce the risk of death compared with aspirin. Compared with treatment with MR-dipyridamole alone, bleeding complications were statistically significantly higher in patients treated with aspirin and MR-dipyridamole in combination with aspirin.

For a cost of up to £20,000-40,000 per additional quality-adjusted life-year: (a) for the stroke and TIA subgroups, ASA-MR-dipyridamole would be the most cost-effective therapy given a 2-year treatment duration as long as all patients were not left disabled by their initial (qualifying) stroke. For a lifetime treatment duration, ASA-MR-dipyridamole would be considered more cost-effective than aspirin. In patients left disabled by their initial stroke, aspirin is the most cost-effective therapy. (b) For the MI and peripheral arterial disease subgroups, clopidogrel would be considered cost-effective for a treatment duration of 2 years. For a lifetime treatment duration, clopidogrel would be considered more cost-effective than aspirin as long as treatment effects on non-vascular deaths are not considered.

Conducted by: L Jones1, S Griffin2, S Palmer2, C Main1,, V Orton1, M Sculpher2, C Sudlow4, R Henderson3, N Hawkins2, R Riemsma1

1. Centre for Reviews and Dissemination; 2. Centre for Health Economics; 3. Nottingham City Hospital; 4. University of Edinburgh

Further details

Project page on HTA Programme website

Related guidance

Commissioned to inform NICE Technology Appraisal 90: Clopidogrel and dipyridamole for the prevention of atherosclerotic events. London: National Institute for Clinical Excellence; 2005

Publications

Jones L, Griffin S, Palmer S, Main C, Orton V, Sculpher M, Sudlow C, Henderson R, Hawkins N, Riemsma R. Clinical effectiveness and cost effectiveness of clopidogrel and modified release dipyridamole in the secondary prevention of occlusive vascular events: a systematic review and economic evaluation. Health Technol Assess. 2004;8(38):1-210

Posters

Jones L, Main C, Riemsma R. Using the adjusted indirect comparison in a health technology assessment (HTA): clopidogrel versus modified-release dipyridamole. Health Technology Assessment International (HTAi) Annual Meeting; 2004 May/June; Krakow, Poland / 12th Cochrane Colloquium; 2004 October; Ottawa, Canada

Funding

Commissioned by the HTA Programme on behalf of NICE