Analytical approach:
The analysis was based on the coronary heart disease policy model (a dynamic Markov cohort model). A 30-year time horizon was considered. The authors stated that the analysis was conducted from the perspective of the health care system.
Effectiveness data:
A selective approach was used to identify data sources, most of which had already been selected in the simulation model. Most epidemiological data were taken from local sources that included National Health and Nutrition Examination Surveys (NHANES) for the years 1999 to 2004, Behavioral Risk Factor Surveillance Survey, US Vital Statistics, National Hospital Discharge Survey and other surveillance databases. Long-term coronary heart disease risk was based on longitudinal data using Framingham equations. The diagnostic accuracy of stress tests and the efficacy of statins and aspirin were key inputs of the model and were taken from various published studies.
Monetary benefit and utility valuations:
Utility valuations were taken from published observational data.
Measure of benefit:
Quality-adjusted life-years (QALYs) were used as the summary benefit measure and were discounted at an annual rate of 3%.
Cost data:
The economic analysis included the costs of drugs, tests, physician visits and lipid profile, coronary heart disease events, care for those individuals who underwent nuclear stress test and developed cancer, and drug-related side effects. Patterns of resource consumption were mostly from the published literature. Most costs were based on Medicare reimbursement rates for direct medical services and average wholesale prices for drugs. Costs were in USA dollars ($). A 3% annual discount rate was applied. The price year was 2009.
Analysis of uncertainty:
Various one-way sensitivity analyses were carried out on selected inputs such as adherence rates, discontinuation rates, efficacy and safety of aspirin, price of statins and diagnostic tests. Other model assumptions were also tested.