Gender differences in clinical outcome and primary prevention defibrillator benefit in patients with severe left ventricular dysfunction: a systematic review and meta-analysis.
BACKGROUND
Women are underrepresented in primary prevention implantable cardioverter-defibrillator (ICD) trials, and data on the benefit of ICD therapy in this subgroup are controversial.


OBJECTIVE
The purpose of this study was to better evaluate the benefit of prophylactic ICD in women by performing a meta-analysis of primary prevention ICD trials that assessed gender differences on the end-points of total mortality, appropriate ICD intervention, and survival benefit of ICD compared with placebo.


METHODS
PubMed, CENTRAL, and other databases were searched in October 2009. Studies were included only if they examined gender differences in the specified end-points, providing the hazard ratio (HR) obtained in multiple Cox regression analyses, and adjusted for all confounding variables.


RESULTS
We retrieved five studies (MADIT-II, MUSTT, SCD-HeFT, DEFINITE, COMPANION) that enrolled 7,229 patients (22% women) with dilated cardiomyopathy (74% ischemic). Compared to men, women had no significant difference in overall mortality (HR 0.96, 95% confidence interval [CI] 0.67-1.39, P = .84) but experienced significantly less appropriate ICD interventions (HR 0.63, 95% CI 0.49-0.82, P < or =.001). The benefit of ICD on mortality was significantly higher in men (HR 0.67, 95% CI 0.58-0.78, P <.001) but did not reach statistical significance in women (HR 0.78, 95% CI 0.57-1.05, P = .1).


CONCLUSIONS
Women enrolled in primary prevention ICD trials have the same mortality compared to men while experiencing significantly less appropriate ICD interventions, thus suggesting a smaller impact of sudden cardiac death on overall mortality in women with dilated cardiomyopathy. These findings may explain the smaller ICD survival benefit among women.
Santangeli
Pasquale
P
Institute of Cardiology, Catholic University of the Sacred Heart, Rome, Italy. pasquale.santangeli@libero.it
Pelargonio
Gemma
G
Dello Russo
Antonio
A
Casella
Michela
M
Bisceglia
Caterina
C
Bartoletti
Stefano
S
Santarelli
Pietro
P
Di Biase
Luigi
L
Natale
Andrea
A
D000368:Aged; D001145:Arrhythmias, Cardiac / Q000401:mortality; D002311:Cardiomyopathy, Dilated / Q000453:epidemiology / Q000401:mortality / Q000628:therapy*; D016757:Death, Sudden, Cardiac / Q000453:epidemiology; D017147:Defibrillators, Implantable; D005260:Female; D006333:Heart Failure / Q000453:epidemiology / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011322:Primary Prevention; D012737:Sex Factors; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000453:epidemiology / Q000628:therapy*