Faculty Bibliography

BACKGROUND: Implantable cardioverter defibrillators (ICDs) are remarkably effective in terminating ventricular arrhythmias, but they are expensive and the extent to which they extend life is unknown. The marginal cost-effectiveness of ICDs relative to amiodarone has not been clearly established. OBJECTIVE: To compare the cost-effectiveness of a third-generation implantable ICD with that of empirical amiodarone treatment for preventing sudden cardiac death in patients at high or intermediate risk. DESIGN: A Markov model was used to evaluate health and economic outcomes of patients who received an ICD, amiodarone, or a sequential regimen that reserved ICD for patients who had an arrhythmia during amiodarone treatment. MEASUREMENTS: Life-years gained, quality-adjusted life-years gained, costs, and marginal cost-effectiveness. RESULTS: For the base-case analysis, it was assumed that treatment with an ICD would reduce the total mortality rate by 20% to 40% at 1 year compared with amiodarone and that the ICD generator would be replaced every 4 years. In high-risk patients, if an ICD reduces total mortality by 20%, patients who receive an ICD live for 4.18 quality-adjusted life-years and have a lifetime expenditure of $88,400. Patients receiving amiodarone live for 3.68 quality-adjusted life-years and have a lifetime expenditure of $51,000. Marginal cost-effectiveness of an ICD relative to amiodarone is $74,400 per quality-adjusted life-year saved. If an ICD reduces mortality by 40%, the cost-effectiveness of ICD use is $37,300 per quality-adjusted life-year saved. Both choice of therapy (an ICD or amiodarone) and the cost-effectiveness ratio are sensitive to assumptions about quality of life. CONCLUSIONS: Use of an ICD will cost more than $50,000 per quality-adjusted life-year gained unless it reduces all-cause mortality by 30% or more relative to amiodarone. Current evidence does not definitively support or exclude a benefit of this magnitude, but ongoing randomized trials have sufficient statistical power to do so

We demonstrated the use of the World Wide Web for the presentation and explanation of a medical decision model. We put on the web a treatment model developed as part of the Cardiac Arrhythmia and Risk of Death Patient Outcomes Research Team (CARD PORT). To demonstrate the advantages of our web-based presentation, we critiqued both the conventional paper-based and the web-based formats of this decision-model presentation with reference to an accepted published guide to understanding clinical decision models. A web-based presentation provides a useful supplement to paper-based publications by allowing authors to present their model in greater detail, to link model inputs to the primary evidence, and to disseminate the model to peer investigators for critique and collaborative modeling