Five RCTs were included in the meta-analysis (n=5,783). None of the included trials had evidence of selection, performance, detection or attrition biases. All trials used a masked committee for adjudication of events and used intention-to-treat analysis.
ICD survival benefit in elderly patients: No statistically significant difference between prophylactic ICD and standard medical therapy was found for all-cause mortality (HR 0.81, 95% CI 0.62 to 1.05; three RCTs). Results were stable after including studies that enrolled patients early after acute myocardial infarction. Sensitivity analysis (age cut-off) did not affect the significance of results.
ICD survival benefit in younger patients: Compared with standard medical therapy, prophylactic ICD therapy significantly reduced all-cause mortality (HR 0.65, 95% CI 0.50 to 0.83; three RCTs). Inclusion of studies that enrolled patients early after acute myocardial infarction and sensitivity analyses (sequential exclusion of studies and age cut-off) did not change the results.
No significant difference was found between younger and older patients (ratio comparison 0.80, 95% CI 0.56 to 1.14).
Adverse effects associated with ICD and medical therapy were summarised in an online appendix.