Cost effective analysis of clopidogrel versus aspirin for high risk patients with established peripheral arterial disease in China.

To assess the cost effectiveness of clopidogrel versus aspirin for high risk patients (pre-existing symptomatic atherosclerosis or multi-vascular territory involvement) with established peripheral arterial disease (PAD) for secondary prevention of atherothrombotic events in a Chinese setting. A Markov model with a lifetime horizon was developed from the perspective of national healthcare system in China. The primary outputs are quality adjusted life years (QALYs), direct medical costs, and the incremental cost effectiveness ratios (ICERs). Clinical efficacy data were obtained from the CAPRIE trial. Drug acquisition cost, other direct medical costs, and utilities were from pricing records and the literature. One-way sensitivity analysis and probabilistic sensitivity analysis (PSA) were conducted to test the robustness of the model on all parameters. In patients with pre-existing atherosclerosis, two years of treatment with clopidogrel and aspirin would yield total QALYs of 8.776 and 8.576 at associated costs of ¥18,777 ($2,838) and ¥12,302 ($1,859), respectively, resulting in an ICER of ¥32,382 ($4,893) per QALY gained. In patients with PVD, secondary prevention with the same drugs would expect to lead to total QALYs of 8.836 and 8.632 at associated costs of ¥18,518 ($2,798) and ¥12,041 ($1,820), respectively, resulting in a corresponding ICER of ¥31,743 ($4,797) per QALY gained. The results were most sensitive to the discount rate for future outcomes and costs. The PSA indicated that the probability of clopidogrel being cost-effective was 100% at the willingness-to-pay threshold of 3 times GDP. Secondary prevention with clopidogrel is an attractive cost-effective option compared with aspirin for high risk patients with established PAD from the perspective of the national healthcare system in Chinese settings.