Analytical approach:
The analysis was based on a Markov model, with a one-year time horizon and a hypothetical 60-year-old patient who had non-emergent percutaneous coronary interventions (PCIs). The authors stated that the analysis was carried out from the perspective of the third-party payer.
Effectiveness data:
The clinical data were from published literature, identified through a review in PubMed. This included randomised controlled trials (RCTs) that compared bare metal stents versus drug-eluting stents and were published between 1990 and November 2009. The bibliographies of the retrieved trials were reviewed. Averages, weighted by sample size, were calculated where more than one study was found for a model parameter. A published meta-analysis was used for the risk of gastrointestinal bleeding while on aspirin and Plavix (dual anti-platelet therapy), which was the key model input.
Monetary benefit and utility valuations:
The utility values were from a published study.
Measure of benefit:
Quality-adjusted life-years (QALYs) were the summary benefit measure.
Cost data:
The economic analysis included the costs of initial stent placement, aspirin, Plavix, coronary artery bypass graft, and gastrointestinal haemorrhage. Procedure-related costs were from the literature and weighted averages were calculated where multiple sources were available. The costs of drugs were from average wholesale prices. All costs were in US dollars ($) and the price year was 2009.
Analysis of uncertainty:
A one-way sensitivity analysis was undertaken varying the risk of gastrointestinal bleeding from dual anti-platelet therapy. A two-way analysis was carried out varying the risk of gastrointestinal bleeding while on aspirin alone and the risk of gastrointestinal bleeding while on dual anti-platelet therapy. A tornado analysis was performed to rank the most influential inputs.