The long-term cost-effectiveness of clopidogrel plus aspirin in patients undergoing percutaneous coronary intervention in Sweden.

BACKGROUND

The Percutaneous Coronary Intervention-Clopidogrel in Unstable Angina to Prevent Recurrent Events (PCI-CURE) study, which examined the effect of adding clopidogrel to aspirin versus aspirin alone in patients with unstable coronary artery disease (CAD) undergoing PCI, found a relative risk reduction in cardiovascular deaths and myocardial infarction among those treated with clopidogrel. In addition, a within-trial cost-effectiveness analysis showed favorable costs per event avoided. However, to estimate the long-term effects, a modeling approach is necessary.

OBJECTIVES

The purpose of this study was to estimate the long-term cost-effectiveness of treating patients undergoing PCI with clopidogrel plus aspirin in Sweden.

METHODS

A Markov model was developed. Transition probabilities were estimated based on a register of patients treated in the coronary care units at 74 (out of 78) hospitals throughout Sweden. Patients were assumed to be treated for 1 year with an effect based on data from the PCI-CURE study. Costs were collected from published sources and recalculated to year-2004 Euros (Euro 1.00 = USD 1.24). Life-years gained were used as the measure of effectiveness. The perspective was that of the Swedish society, with a separate analysis using a health care cost perspective.

RESULTS

After inclusion and exclusion criteria were applied, 3474 patients were included in the model analysis. The model predicted a net gain in survival of 0.04 year per patient when adding clopidogrel. This yielded a net increase of Euros 449 if only direct costs were included; with indirect costs, the net increase was Euros 332. The resulting cost-effectiveness ratios were Euros 10,993 and Euros 8127 per life-year gained.

CONCLUSIONS

The predicted cost-effectiveness ratios were well below the threshold values generally considered cost-effective. Adding clopidogrel to aspirin appeared to be cost-effective in this model analysis of patients with unstable CAD undergoing PCI in Sweden.