Implantable Cardioverter Defibrillators: Do Women Fare Worse Than Men? Gender Comparison in the INTRINSIC RV Trial
Dr. Russo reports participation in research grants from Medtronic, St. Jude Medical, Boston Scientific, and Biotronic, and honoraria received for lectures from Medtronic, St. Jude Medical, and Boston Scientific. Dr. Day reports consultantships for St. Jude Medical and Boston Scientific. Dr. Olshansky reports participation in research grants and compensation and honoraria for participation in a speakers’ bureau from Boston Scientific, Medtronic, St. Jude Medical, and Novartis. Dr. Stolen is an employee of Boston Scientific, with stock ownership. Mr. Mullen's employer has a service contract with Boston Scientific. Dr. Doraiswamy is an employee of Boston Scientific, sponsor of the study. Dr. Lerew was an employee of Boston Scientific when the study research was conducted, and has stock ownership in the company; he is currently employed by Medtronic.
Abstract
Introduction: Due to limited enrollment of women in previous trials, there is a paucity of data comparing outcome and arrhythmic events in men versus women with implantable cardioverter defibrillators (ICDs).
Methods and Results: We analyzed outcome of patients in the INTRINSIC RV (Inhibition of Unnecessary RV Pacing with AV Search Hysteresis in ICDs) trial based on gender. Women comprised 19% (293/1530) of the INTRINSIC RV population. Compared with men, women were less likely to have coronary disease, ischemic cardiomyopathy, and hyperlipidemia, and were more likely to have congestive heart failure and diabetes. Women were less likely to receive beta blockers and ACE inhibitors, and more likely to receive diuretics. Over 10.8 ± 3.5 months of follow-up, unadjusted mortality was higher in women than men (6.8% vs 4.1%, P = 0.04). Heart failure hospitalizations occurred in 7.9% of women versus 5.7% of men (P = 0.13). After adjustment for baseline differences and drug therapy, there was no significant difference in mortality between men and women. Adverse events were observed more often in women. There were no gender differences in the percentage of patients receiving appropriate or inappropriate ICD shocks.
Conclusions: In INTRINSIC RV, women receiving ICDs differed from men regarding baseline characteristics and drug therapy. After adjusting for baseline differences and medical therapy, there were no differences in heart failure hospitalization, survival, or ICD shock therapy during follow-up. Apparent undertreatment of heart failure and greater frequency of adverse advents in women receiving ICDs warrant further investigation.
