Economics methods in the Clinical Outcomes Utilizing percutaneous coronary Revascularization and Aggressive Guideline-driven drug Evaluation (COURAGE) trial

Percutaneous coronary intervention (PCI) remains a major therapeutic option for the treatment of chronic coronary artery disease. In the COURAGE trial, 2287 patients with chronic coronary disease were randomized between PCI with medical management and medical management alone. Embedded within the COURAGE trial is a detailed economic analysis being conducted in three health care systems: the US Veterans Administration (VA), Canada, and the US non-VA. Resource use and costs are being collected for each system and overall. Survival is assessed internally in the trial with mean follow-up of 4.5 years. Long-term mean survival will be estimated by projecting survival beyond the trial period by extrapolating the in-trial hazard rates. Utility is being assessed at baseline and at 1, 3, and 6 months and annually thereafter, using a computer-administered standard gamble. Quality-adjusted life years are calculated by multiplying survival by utility. The incremental cost-effectiveness ratio of PCI will be defined as the additional cost of PCI divided by the gain in life years and quality-adjusted life years. The 95% confidence regions of efficacy and costs will be determined by bootstrap over a range of acceptability thresholds, which will then be displayed in the cost-effectiveness plane and as a cost-effectiveness acceptability curve. A multilevel regression model will assess cost-effectiveness from a net benefit perspective. These approaches should provide the most detailed assessment available of the cost-effectiveness of PCI for coronary artery disease.