Holmberg MJ, et al. - This meta-analysis was performed to evaluate studies comparing bystander automated external defibrillator (AED) use to no AED use in regard to clinical outcomes in out-of-hospital cardiac arrest (OHCA), and to give a descriptive summary of studies on the cost-effectiveness of bystander AED use. Although the quality of evidence was low to very low, the evidence supported the relationship between bystander AED use and improved clinical outcomes.