Cost-Effectiveness of Simvastatin Plus Ezetimibe for Cardiovascular Prevention in Patients With a History of Acute Coronary Syndrome: Analysis of Results of the IMPROVE-IT Trial

Background: Simvastatin plus ezetimibe reduced the risk of cardiovascular events in the IMProved Reduction of Outcomes: Vytorin Efficacy International (IMPROVE-IT) study. The aim of this study is to investigate the cost-effectiveness of adding ezetimibe to simvastatin treatment for patients with ACS based on the recently completed IMPROVE-IT trial. Methods: We constructed a Markov state-transition model to evaluate the costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness (ICER) associated with co-therapy compared with simvastatin alone from a health care perspective. We ran separate base-case analyses assuming a trial-length and longer term follow-up. One-way sensitivity analyses were used to explore uncertainty in model parameters. Results: In the trial-length model, the ICERs compared with simvastatin alone were $114,400 per QALY for the combination therapy. In 5- and 10-year time horizons, the ICERs remained above the cost-effectiveness threshold of $50,000 per QALY. In the lifetime horizon model, The ICER was $45,046 per QALY for combination treatment compared with simvastatin alone. The combination therapy is cost-effective at an 80% decrease in the current branded simvastatin and ezetimibe cost. Probabilistic sensitivity analysis suggested simvastatin and ezetimibe co-therapy would be a cost-effective alternative to simvastatin monotherapy 60.7% of the time. Conclusions: In our trial-length, 5-year, and 10-year models, the co-therapy was not a cost-effective alternative; however, as follow-up was extended to lifetime, the co-therapy became a cost-effective treatment compared with the simvastatin monotherapy in patients with histories of ACS.