Economic assessment of the secondary prevention of ischaemic events with lysine acetylsalicylate.

OBJECTIVE To analyse the economic benefits, in comparison with placebo, of the secondary prevention of ischaemic stroke and myocardial infarction (MI) with lysine acetylsalicylate (Kardégic) in patients with a history of ischaemic stroke, MI or stable and unstable angina pectoris. DESIGN AND SETTING This was a modelling study from the perspectives of direct medical costs, the social security system and society in France. METHODS Efficacy data for the secondary prevention of ischaemic events were derived from the Antiplatelet Trialists' Collaboration meta-analysis on antithrombotics. The rates and costs of ischaemic disease and of serious gastrointestinal adverse affects arising from long term aspirin treatment, as well as the costs of treatment with lysine acetylsalicylate, were taken from published sources, using French data where possible. RESULTS From the social security perspective, the estimated cost-effectiveness ratios show that the prevention of MI in patients with a history of unstable angina (with a 1-year follow-up) is a cost-saving strategy, with net benefits ranging from $US5703 (1996 prices) per avoided MI for lysine acetylsalicylate 300 mg/day to $US5761 per avoided MI for lysine acetylsalicylate 75 mg/day. The prevention of MI and stroke is also a cost-saving strategy in patients with prior MI [net benefits in a 2-year follow-up (5% discount rate) ranging from $US15 to $US494 per avoided MI and from $US37 to $US1170 per avoided stroke]. This was also true in patients with prior ischaemic stroke (net benefits in a 3-year follow-up ranging from $US610 to $US2082 per avoided MI and from $US176 to $US599 per avoided stroke). Finally, a 4-year follow-up in patients with a history of stable angina pectoris shows that prophylactic treatment with lysine acetylsalicylate is associated with net costs per avoided MI, ranging from $US4375 to $US3608 per avoided event. Sensitivity analysis confirmed that prophylaxis with lysine acetylsalicylate in patients at high risk of cardiovascular and cerebrovascular events results in savings in social security expenditure. CONCLUSIONS Our results underline the high economic benefit of using lysine acetylsalicylate to prevent secondary ischaemic stroke and MI in patients at high risk of cardiovascular and/or cerebrovascular events, leading to savings for the social security system and society.