Survival in octogenarians receiving implantable defibrillators

Background Athough clinical trials have expanded implantable defibrillator (ICD) indications, octogenarians have been poorly represented in these studies. Overall, survival in this subgroup is ill-defined. Methods Consecutive patients >= 80 years of age at ICD implant between July 1995 and September 2003 were retrospectively analyzed. Kaplan-Meier survival analysis was performed, and mortality predictors were identified. Consecutive nonelderly patients aged 60 to 70 years (60-70 group) who received ICDs over the same period were analyzed as a reference. Mortality predictors in the >= 80 group were compared to the 60-to-70 group. Results A total of 348 patients (age, >= 80 years [n = 107]; age, 60-70 years [n = 241]) were included. Mean follow-up time for the entire cohort was 3.3 +/- 2.2 years. Other than the estimated glomerular filtration rate (eGFR) (58 +/- 22 vs 66 +/- 22 mL/min) in the >= 80 group versus the 60-to-70 group, no other differences in baseline characteristics were observed. Median survival was 4.2 years after implant in the >= 80 group versus 7 years in the 60-to-70 group (P < .01). Mortality predictors in the >= 80 group included ejection fraction (EF) <= 30% (hazard ratio [HR], 2.2; 95% confidence interval [cl], 1.3-4.0) and eGFR < 60 mL/min (HR, 2.2; 95% Cl, 1.3-3.7). In the 60-to-70 group, EF <= 30% (HR, 2.7; 95% Cl, 1.6-4.5), eGFR < 60 mL/min (HR, 3.4; 95% Cl, 2.2-5.3), diabetes (HR, 1.8; 95% Cl, 1.9-2.9), and QRS width > 120 ms (HR, 2.1; 95% Cl, 1.4-3.3) predicted mortality. QRS > 120 ms and diabetes were not predictors in octogenarians (HR, 1.1 and 1.5, respectively; 95% Cl, 0.7-1.9 and 0.8-2.7, respectively). Analysis of octogenarians subgrouped by EF <= 30% and eGFR <60 mL/min identified patients whose median survival was 6.1 years (neither predictor present; n = 28), 4.7 years (either predictor present; n = 46), and 19 months (both predictors present; n = 33) (P < .01 between groups). Survival analysis in the >= 80-year-old cohort grouped by eGFR quartile identified groups with median survival of 5.6, 4.7, 3.5 years, and 18 months, respectively, in the highest to the lowest eGFR quartile (> 75, 61-75, 41-60, and < 41 mL/min). Conclusions Median survival in octogenarian ICD recipients is greater than 4 years. In addition to baseline EF, eGFR is a strong predictor of mortality in elderly ICD candidates. These easily identifiable clinical variables may assist clinical decision making and help to provide appropriate post-ICD implant survival expectations in this elderly patient group.