The relationship between glomerular filtration rate and survival in patients treated with an implantable cardioverter defibrillator

Objectives: We explored the association between renal insufficiency (RI) and mortality among patients treated with an implantable cardioverter defibrillator (ICD). Background: Randomized trials have shown improvements in survival among select patients treated with an ICD. Renal insufficiency patients have a high risk of cardiac death; however, it is not clear whether the ICD has a positive effect on survival in this group of patients. Methods: This was a retrospective review of a single-center experience of 346 patients treated with an ICD. Patients were stratified into 4 groups according to their glomerular filtration rate (eGFR; expressed as mL/min/ -1.73 m(2)) at implantation: group I, > 75.0; group II, -60.0 to 74.9; group III, -45.0 to 59.9; and group IV, - <= 45.0. All-cause mortality was the primary end point, with differences in survival times among the 4 groups of patients expressed in Kaplan-Meier curves. Results: Mean follow-up was 3.5 y (range 0.1 to 12.9 y), during which 67 patients died (19%). Mortality in each eGFR group was: I -6.8%, II -13.8%, III -11.5%, IV -45.8% (p<0.001). Survival times (mean, y) were I, 3.74; II, 3.66; III, 3.38, and IV, 2.82. The presence of diabetes was not a factor in the outcomes. Conclusions: Patients treated with an ICD with an eGFR of <= 45.0 mL/min/1.73 m(2) have a significantly shorter survival time than those patients with an eGFR > 45.0 mL/min/1.73 m(2). Patients with an eGFR >45.0 mL/min/1.73 m(2) appear to have equally good outcomes when treated with an ICD. This may have implications for patient selection for ICD therapy.