Examination of the effect of implantable cardioverter-defibrillators on health-related quality of life: based on results from the Multicenter Automatic Defibrillator Trial-II.

While implantable cardioverter-defibrillators (ICDs) improve survival, their benefit in terms of health-related quality of life (HRQOL) is negligible. To examine how shocks and congestive heart failure (CHF) mediate the effect of ICDs on HRQOL. The US patients from the MADIT-II (Multicenter Automatic Defibrillator Trial-II) trial (n = 983) were randomized to receive an ICD or medical treatment only. HRQOL was assessed using the Health Utility Index 3 at baseline and 3, 12, 24, and 36 months following randomization. Logistic regressions were used to test for the effect of ICDs on the CHF indicator, and linear regressions were used to examine the effect of ICD shocks and CHF on HRQOL in living patients. We used a Monte Carlo simulation and a parametric Weibull distribution survival model to test for the effect of selective attrition. Observations were clustered by patients and robust standard errors (RSEs) were used to control for the non-independence of multiple observations provided by the same patient. Patients in the ICD arm had 41% higher odds of experiencing CHF since their last assessment compared with those in the control arm (RSE = 0.19, p = 0.01). Developing CHF reduced HRQOL at the subsequent visit by 0.07 (p < 0.01). Having ICD shocks reduced overall HRQOL by 0.04 (p = 0.04) at the subsequent assessment. The negative effect of ICD firing on HRQOL was an order of magnitude greater than the effect of CHF. A higher prevalence of CHF and shocks among patients with ICDs and their negative effect on HRQOL may partially explain the lack of HRQOL benefit of ICD therapy.

Health-related quality of life consequences of implantable cardioverter defibrillators: results from MADIT II.

BACKGROUND: Implantable cardioverter defibrillators (ICDs) improve survival and extend lives of patients with severe heart disease. OBJECTIVE: We sought to evaluate the impact of ICDs on health-related quality of life (HRQOL) during the first 3 years after implantation. SUBJECTS: A total of 1089 patients from the Multicenter Automatic Defibrillator Implantation Trial II (MADIT II) were randomized to an ICD or medical treatment only. MEASURES: Health Utility Index (HUI3) at baseline, 3, 12, 24, and 36 months following randomization; survival data. RESEARCH DESIGN: We constructed mean profiles of HRQOL for living patients, estimated overall quality-adjusted life years (QALYs), separately by treatment arm, and calculated cumulative QALY gains/losses as the difference between the areas under the treatment specific HRQOL profiles. Multivariate fixed effect regression models were developed to impute the missing HRQOL data using baseline patient characteristics (age, gender, treatment, HUI3 score, diabetes, diuretics use, and NYHA class). Bootstrapped standard errors were calculated for the estimated differences in HRQOL gains/losses between treatment arms. Similarly, we performed subgroup analyses (by gender, age, and baseline NYHA class, blood urine nitrogen, ejection fraction, and QRS). RESULTS: There were no differences in QALYs loss for living patients by treatment group (-0.037, P = 0.64) or in overall QALYs loss by treatment group (0.043, P = 0.37) over 3 years. In subgroup analysis, female subjects demonstrated a trend towards greater survival benefit (0.298, P = 0.07) and overall QALYs (0.261, P = 0.14). CONCLUSIONS: Adverse effects of the ICD on HRQOL together with lower HRQOL among survivors may offset the 3-year survival benefits of ICDs.