Effect of clinical risk stratification on cost-effectiveness of the implantable cardioverter-defibrillator the - Canadian Implantable Defibrillator Study

Background-Three randomized clinical trials showed that implantable cardiov erter-defibrillators (ICDs) reduce the risk of death in survivors of ventri cular tachyarrhythmias, but the cost per year of life gained is high. A sub study of the Canadian Implantable Defibrillator Study (CIDS) showed that 3 clinical factors, age greater than or equal to 70 years, left ventricular e jection fraction greater than or equal to 35%, and New York Heart Associati on class III, predicted the risk of death and benefit from the ICD. We esti mated the extent to which selecting patients for ICD therapy based on these risk factors makes ICD therapy more economically attractive. Methods and Results-Patients in CIDS were grouped according to whether they had greater than or equal to2 of 3 risk factors. Incremental cost-effectiv eness of ICD therapy was computed as the ratio of the difference in mean co st to the difference in life expectancy between the 2 groups. Over 6.3 year s, the mean cost per patient in the ICD group was Canadian (C) $87 715 vers us $38 600 in the amiodarone group (C$1 approximate to US$0.67). Life expec tancy for the ICD group was 4.58 years versus 4.35 years for amiodarone, fo r an incremental cost-effectiveness of ICD therapy of C$213 543 per life-ye ar gained. The cost per life-year gained in patients with greater than or e qual to2 factors was C$65 195, compared with C$916 659 with <2 risk factors . Conclusions-The cost-effectiveness of ICD therapy varies by patient risk fa ctor status. The use of ICD therapy in patients who have greater than or eq ual to2 risk factors of age ?70 years, left ventricular ejection fraction l ess than or equal to 35%, and NYHA class III is C$65 195 to gain a year of life.