Meta-analysis: age and effectiveness of prophylactic implantable cardioverter-defibrillators.
BACKGROUND
Implantable cardioverter-defibrillators (ICDs) for the primary prevention of sudden cardiac death have been proven effective in several clinical trials.


OBJECTIVE
To summarize evidence about the effectiveness of ICDs versus standard medical therapy for the primary prevention of sudden cardiac death in different age groups of patients with severe left ventricular dysfunction.


METHODS
MEDLINE, Embase, CENTRAL, BioMed Central, Cardiosource, ClinicalTrials.gov, and ISI Web of Science (January 1970 to April 2010) were searched with no language restrictions.


METHODS
Two independent reviewers screened titles and abstracts to identify randomized, controlled trials of prophylactic ICD versus medical therapy in patients with severe left ventricular dysfunction that provided data about mortality outcomes for different age groups.


METHODS
Two independent reviewers assessed risk for bias of trials and extracted patient and study characteristics and hazard ratios (HRs) relevant to all-cause mortality.


RESULTS
Five trials (MADIT-II, DEFINITE, DINAMIT, SCD-HeFT, and IRIS) that enrolled 5783 patients (44% were elderly) were included. The primary analysis, which excluded the 2 trials enrolling patients early after acute myocardial infarction (DINAMIT and IRIS), found that prophylactic ICD therapy reduced mortality in younger patients (HR, 0.65 [95% CI, 0.50 to 0.83]; P < 0.001). A smaller survival benefit was found in elderly patients (HR, 0.75 [95% CI, 0.61 to 0.91]) that was not confirmed when MADIT-II patients older than 70 years were excluded or when data from DINAMIT and IRIS were included [corrected].


CONCLUSIONS
Four potentially eligible trials were not included in the meta-analysis because mortality data by age group were not available. Adjustment for differences in comorbid conditions and medical therapies among patients enrolled in the trials was not possible.


CONCLUSIONS
Available data suggest that prophylactic ICD therapy may be less beneficial for elderly patients with severe left ventricular dysfunction than for younger patients [corrected].


BACKGROUND
None.
Catholic University of the Sacred Heart, Rome, Italy. pasquale.santangeli@libero.it
Pasquale
P
Santangeli
Luigi
L
Di Biase
Antonio
A
Dello Russo
Michela
M
Casella
Stefano
S
Bartoletti
Pietro
P
Santarelli
Gemma
G
Pelargonio
Andrea
A
Natale
D000367:Age Factors; D016757:Death, Sudden, Cardiac / Q000453:epidemiology / Q000517:prevention & control*; D017147:Defibrillators, Implantable / Q000009:adverse effects; D006801:Humans; D011322:Primary Prevention; D016896:Treatment Outcome; D014481:United States; D018487:Ventricular Dysfunction, Left / Q000628:therapy*