Economics, health-related quality of life, and cost-effectiveness methods for the TACTICS (Treat Angina with Aggrastat® [tirofiban] and Determine Cost of Therapy with Invasive or Conservative Strategy)–TIMI 18 trial

Concern over escalating health care costs has led to increasing focus on economics and assessment of outcome measures for expensive forms of therapy. This is being investigated in the Treat Angina With Aggrastat [tirofiban] and Determine Cost of Therapy with Invasive or Conservative Strategy (TACTICS)-TIMI 18 trial, a randomized trial comparing outcome of patients with unstable angina or non-Q-wave myocardial infarction treated with tirofiban and then randomized to an invasive versus a conservative strategy. Hospital and professional costs initially and over 6 months, including outpatient costs, will be assessed. Hospital costs will be determined for patients in the United States from the UB92 formulation of the hospital bill, with costs derived from charges using departmental cost to charge ratios. Professional costs will be determined by accounting for professional services and then converted to resource units using the Resource Based Relative Value Scale and then to costs using the Medicare conversion factor. Follow-up resource consumption, including medications, testing and office visits, will be carefully measured with a Patient Economic Form, and converted to costs from the Medicare fee schedule. Health-related quality of life will be assessed with a specific instrument, the Seattle Angina Questionnaire, and a general instrument, the Health Utilities Index at baseline, 1, and 6 months. The Health Utilities Index will also be used to construct a utility. By knowing utility and survival, quality-adjusted life years will be determined. These measures will permit the performance of a cost-effectiveness analysis, with the cost-effectiveness of the invasive strategy defined and the difference in cost between the invasive and conservative strategies divided by the difference in quality-adjusted life years. The economic and health-related quality of life aspects of TACTICS-TIMI 18 are an integral part of the study design and will provide a comprehensive understanding of the impact of invasive versus conservative management strategies on a broad range of outcomes after hospitalization for unstable angina or non-Q-wave myocardial infarction.