Cost-Effectiveness of Clopidogrel vs Aspirin Monotherapy After Percutaneous Coronary Intervention

Figures

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  Figure 1. Model Schematic The structure of the Markov model is shown. The cohort entered the model in the “well on single antiplatelet” state. Yearly, patients were at risk of admission for acute coronary syndrome (ACS), repeat revascularization, bleeding, ischemic stroke, and death. “Post-PCI,” “post-stroke,” and “death” were modeled as health states that the patient could move into according to the occurrence of a clinical event. PCI = percutaneous coronary intervention.

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  Figure 2. Selected Results of 1-Way Sensitivity Analysis A tornado diagram for clopidogrel vs aspirin monotherapy is presented to visualize the one-way sensitivity analysis. For some parameters, the value of the incremental cost-effectiveness ratio seemed infinite due to the change in the direction of incremental effects. The tornado diagram was therefore presented as an incremental net monetary benefit (INMB), assuming a willingness-to-pay threshold of $30,581. The top 10 variables with considerable INMB variation are shown. The vertical line represents the base-case INMB. The x-axis represents the ranges of INMB when the parameter values were varied over plausible ranges. Blue color indicates when each parameter has values lower than the base-case value within the range, and red color indicates when each parameter has higher values. ACS = acute coronary syndrome; USD = U.S. dollar.

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  Figure 3. Cost-Effectiveness Acceptability Curves Probabilistic sensitivity analyses were performed on base-case and scenario, assuming no difference in cardiovascular mortality. The dashed lines represent the willingness-to-pay (WTP) threshold of $30,581. The curves show the probabilities that each monotherapy is cost-effective at varying cost-effectiveness threshold ratios. QALY = quality-adjusted life-year; USD = U.S. dollar.

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  Central Illustration. Results of Cost-Effectiveness Analyses Between Clopidogrel and Aspirin Monotherapy During the chronic maintenance period after percutaneous coronary intervention, clopidogrel monotherapy did not increase quality-adjusted life-years (QALYs) compared with aspirin monotherapy, despite increased costs in South Korea. In the United Kingdom and the United States, clopidogrel monotherapy decreased health care costs but was not associated with QALY gains. Scenario analysis with the assumption of no difference in mortality between the 2 groups show that clopidogrel was the dominant treatment strategy in the United Kingdom and the United States, but it was not cost-effective in South Korea. GBP = British pound; USD = U.S. dollar.