Abstract 3855: Cost-Effectiveness of Clopidogrel + Aspirin vs. Aspirin Alone for Secondary Prevention of Cardiovascular Events: Results from the CHARISMA Trial
Background: A prespecified analysis of the CHARISMA trial suggests that adding clopidogrel (C) to aspirin (A) reduces cardiovascular (CV) events in pts with established coronary artery, cerebrovascular, or peripheral arterial disease. The cost-effectiveness (C-E) of this strategy is unknown.
Methods: In CHARISMA, 12153 pts with established CV disease were randomized to C + A (n = 6062) vs. A alone (n = 6091). Patient level costs were assessed for hospitalizations, MD services, outpt care, and medications based on in-trial resource utilization and 2004 U.S. unit costs. Life expectancy (LE) projections were derived for each surviving pt contingent on the occurrence of non-fatal CV events using statistical models based on a CHARISMA-eligible cohort from the Saskatchewan Health database. Costs and LE were discounted at 3%/yr for the primary C-E analysis, and bootstrap resampling was used to assess the precision of the C-E estimates.
Results: Over a median follow-up duration of 28 months, assignment to C + A was associated with a 12.5% relative reduction in the incidence of CV death, MI, or stroke (6.9% vs. 7.9%, p = 0.045). Mean costs were increased by $2884 for C + A, mainly due to the study drug, while projected LE increased by 0.075 yrs due to fewer fatal and non-fatal events during the trial (see Table⇓). The resulting incremental C-E ratio was $38,617 per life-year gained for C + A vs. A alone. Bootstrap resampling demonstrated that C + A was economically attractive at a threshold of $50,000/life-year gained in 68.3% of replicates, while C + A was dominated in 4.9% of replicates.
Conclusion: Among pts with established CV disease, adding clopidogrel to aspirin for secondary prevention appears to increase life expectancy modestly at a cost generally considered acceptable within the U.S. healthcare system.