Meta-analysis: age and effectiveness of prophylactic implantable cardioverter-defibrillators

Area of Science:

• Cardiology
• Medical Devices
• Public Health

Background:

• Implantable cardioverter-defibrillators (ICDs) are established for primary prevention of sudden cardiac death.
• Severe left ventricular dysfunction is a key indication for ICDs.

Purpose of the Study:

• To evaluate the effectiveness of ICDs versus standard medical therapy.
• To compare ICD efficacy in different age groups for primary prevention of sudden cardiac death.

Main Methods:

• Systematic review and meta-analysis of randomized controlled trials.
• Searched multiple databases (MEDLINE, Embase, etc.) from January 1970 to April 2010.
• Extracted mortality data and hazard ratios for all-cause mortality by age group.

Main Results:

• Five trials with 5783 patients were included; 44% were elderly.
• Prophylactic ICD therapy significantly reduced mortality in younger patients.
• A smaller, less consistent survival benefit was observed in elderly patients.

Conclusions:

• Prophylactic ICD therapy may offer less benefit to elderly patients with severe left ventricular dysfunction compared to younger patients.
• Limitations include unavailable age-specific mortality data in some trials and inability to adjust for comorbidities.