Abstract 1658: Women Fare Worse With Implantable Cardioverter Defibrillators
Background: Gender differences exist with regard to risk of sudden cardiac death. Due to limited enrollment of women in previous trials, there is a paucity of data comparing outcome and arrhythmic events in men vs. women with implantable cardioverter defibrillators (ICDs).
Methods: We analyzed the influence of gender on outcome of patients receiving ICDs in the INTRINSIC RV (Inhibition of Unnecessary RV Pacing with AV Search Hysteresis in ICDs) trial, one of the largest ICD trials to date.
Results: Women comprised 19% (293/1530) of the INTRINSIC RV population. Mean follow-up was 10.8 ± 3.5 months. Compared to men, women were less likely to have coronary disease, ischemic cardiomyopathy, and hyperlipidemia, and more likely to have congestive heart failure and diabetes. (Table⇓) Women were less likely to receive beta blockers and ACE inhibitors, and more likely to receive diuretics. Mortality was higher in women than in men (6.8% vs. 4.1%, p=0.048). Heart failure hospitalizations occurred in 7.9% of women vs. 5.7% of men (p=0.16). Despite the mortality difference, there were no gender differences in the percentage of patients who received any shocks (men: 11.9%, 95% CI = 10.1%–13.8%; women: 13.3%, 95% CI 9.6%–17.7%; p = 0.414) or inappropriate shocks (men: 6.0%, 95% CI = 4.8%–7.5%; women 7.2%, 95% CI = 4.5%–10.8%; p = 0.804). A logistic regression model for death based on gender and other characteristics revealed an adjusted odds ratio of 1.22 (0.69–2.16).
Despite the ICD, women had a greater risk of dying.
This worse outcome occurs despite a similar percentage of men and women receiving ICD shock therapy.
The explanation for these findings is uncertain, but may be related to gender differences in baseline characteristics and undertreatment of heart failure in women receiving ICDs. Further investigation regarding differences in outcome by gender in an ICD population is warranted.