A cost-effectiveness analysis of combination antiplatelet therapy for high-risk acute coronary syndromes: clopidogrel plus aspirin versus aspirin alone.
BACKGROUND
Although clopidogrel plus aspirin is more effective than aspirin alone in preventing subsequent vascular events in patients with unstable angina, the cost-effectiveness of this combination has yet to be examined in this high-risk population.


OBJECTIVE
To determine the cost-effectiveness of clopidogrel plus aspirin compared with aspirin alone.


METHODS
Cost-utility analysis.


METHODS
Published literature.


METHODS
Patients with unstable angina and electrocardiographic changes or non-Q-wave myocardial infarction. time horizon: Lifetime.


CONCLUSIONS
Societal.


METHODS
Combination therapy with clopidogrel, 75 mg/d, plus aspirin, 325 mg/d, for 1 year, followed by aspirin monotherapy, was compared with lifelong aspirin therapy, 325 mg/d.


METHODS
Lifetime costs, life expectancy in quality-adjusted life-years (QALYs), and the incremental cost-effectiveness ratio.


RESULTS
Patients treated with aspirin alone lived 9.51 QALYs after their initial event and incurred expenses of 127,700 dollars; the addition of clopidogrel increased life expectancy to 9.61 QALYs and costs to 129,300 dollars. The incremental cost-effectiveness ratio for clopidogrel plus aspirin compared with aspirin alone was 15,400 dollars per QALY.


RESULTS
The analysis of 1 year of therapy was robust to all sensitivity analyses. In the probabilistic sensitivity analysis, fewer than 3% of simulations resulted in cost-effectiveness ratios over 50,000 dollars per QALY. The cost-effectiveness of longer combination therapy depends critically on the balance of thrombotic event rates, durable efficacy, and the increased bleeding rate in patients taking clopidogrel.


CONCLUSIONS
This analysis may not apply to patients with severe heart failure, those undergoing long-term anticoagulant therapy, those recently managed with revascularization, or those undergoing short-term treatment with glycoprotein IIb/IIIa inhibitors.


CONCLUSIONS
In patients with high-risk acute coronary syndromes, 1 year of therapy with clopidogrel plus aspirin results in greater life expectancy than aspirin alone, at a cost within the traditional limits of cost-effectiveness. The durable efficacy of clopidogrel relative to the risk for hemorrhage should be further explored before more protracted therapy can be recommended.
Schleinitz
Mark D
MD
Division of General Internal Medicine, Brown University and Rhode Island Hospital, Providence, Rhode Island 02903, USA. Mark_Schleinitz@Brown.edu
Heidenreich
Paul A
PA
D000789:Angina, Unstable / Q000188:drug therapy*; D001241:Aspirin / Q000009:adverse effects / Q000627:therapeutic use*; D002318:Cardiovascular Diseases / Q000517:prevention & control*; D000077144:Clopidogrel; D003198:Computer Simulation; D003362:Cost-Benefit Analysis; D004562:Electrocardiography; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D008390:Markov Chains; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy*; D010975:Platelet Aggregation Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D019057:Quality-Adjusted Life Years; D012008:Recurrence; D012307:Risk Factors; D012680:Sensitivity and Specificity; D020521:Stroke / Q000517:prevention & control; D013988:Ticlopidine / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use*
D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin