Abstract 9400: Obesity is Associated With Lower Mortality in Patients With Implantable Cardioverter-Defibrillator

Abstract

Introduction: Higher body mass index (BMI) is associated with increased cardiovascular risk factors. Recent studies indicate an inverse relationship between obesity and overall survival after acute cardiovascular events. However, in patients at high risk of sudden cardiac death (SCD), the impact of obesity on mortality is not defined. Hypothesis: We assessed whether a paradoxical relationship between BMI and risk of overall mortality is present in patients with an implantable cardioverter-defibrillator (ICD). Methods: Consecutive patients who received an ICD for prevention of SCD at our institution from January 2010 to December 2011 were retrospectively divided into three groups based on BMI. Clinical parameters and long-term outcomes as determined by Kaplan-Meier and logistic regression models were compared among normal (BMI <25), overweight (BMI 25-29.9) and obese (BMI ≥30) groups. Results: Of 1,151 patients (mean age 67 ± 13 years; 67% male), 26% had normal BMI, 32% were overweight and 42% were obese. There were no significant baseline differences in mean left ventricular ejection fraction (30 ± 12%), type of ICD implanted or indication for implantation, prior syncope or cardiac arrest, and prevalence of heart failure or atrial fibrillation. Patients with normal BMI were older (68 ± 14 years) compared with the overweight (68 ± 13 years) and obese (62 ± 12 years) groups (p<0.001). Despite significantly higher prevalences of diabetes, hypertension, ischemic heart disease and prior myocardial infarction, the higher BMI groups had lower overall mortality than the normal BMI group. Median time to death after ICD implantation also was significantly shorter in the normal BMI group (figure). On multivariate logistic regression analysis, higher BMI (including obese and overweight groups) was protective against mortality. Conclusion: Patients with an ICD who were obese or overweight had lower mortality than those with normal BMI.