Dual antiplatelet therapy (DAPT), aspirin with one P2Y receptor inhibitor, is routinely prescribed after coronary stenting. Extended duration of DAPT might reduce the rates of late stent thrombosis for patients with drug eluting stents (DES), but increase the risk of bleeding. This study aims to evaluate the clinical and economic outcomes of DAPT beyond 1 year in DES patients.

METHODS:

A lifelong Markov model was developed to compare long-term with short-term DAPT (clopidogrel plus aspirin). Patients who entered the model were survivors after receiving 12-month DAPT without any ischemic or bleeding events. Patients in the long-term DAPT arm would continue to receive DAPT (clopidogrel plus aspirin), while patients in the short-term group would receive aspirin for 18 months. Model inputs were derived from published literature. Direct medical costs, quality-adjusted life-years (QALYs) gained, and incremental cost-effectiveness ratio (ICER) were primary outcomes simulated in the model from the perspective of US healthcare provider.

RESULTS:

Base-case results showed short-term DAPT was more costly (USD74,389) with more QALYs gained (8.1086 QALYs) compared to long-term DAPT. Short-term DAPT was a cost-effective strategy with ICER (28,675 USD/QALY) less than the willingness-to-pay threshold (50,000 USD/QALY). One-way sensitivity analysis found the base-case results were subject to hazard ratios of nonfatal stroke, major bleeding, cardiovascular death, and non-cardiovascular death of long-term versus short-term DAPT. In probabilistic sensitivity analysis, short-term DAPT was USD789 (95% CI: USD770-USD808) more costly and gained 0.06 (95% CI: 0.059-0.061) more QALYs compared to long-term DAPT. The 10,000 Monte Carlo simulations revealed short-term DAPT and long-term DAPT could be the preferred strategy in 89.73% and 10.27% of the time, respectively.

CONCLUSIONS: Short-term DAPT seems to be a cost-effective strategy compared to long-term DAPT in DES patients who were event free after initial 12-month DAPT.