All cause mortality of cardiac resynchronization therapy with implantable cardioverter defibrillator: A meta-analysis of randomized controlled trials

PurposeCardiac resynchronization therapy with implantable cardioverter defibrillator (CRT-D) has been shown to improve symptoms in patients with chronic heart failure (CHF). However, reduction of all cause mortality is being debated. To evaluate whether CRT-D reduces all cause mortality compared with no-CRT-D in patients with CHF, a meta-analysis of randomized controlled trials was performed.Data sourcesData sources are MEDLINE (1994–2008), EMBASE (1994–2008), the Cochrane Controlled Trials Register (Second Quarter, 2008), the National Institutes of Health Clinical Trials.gov database of clinical trials and the US Food and Drug Administration Website (1994–2008). Search terms included cardiac resynchronization therapy with implantable cardioverter defibrillator, biventricular implantable cardioverter defibrillator, cardiac resynchronization therapy, and CRT-D.Review methodsTwo reviewers independently assessed trial eligibility and quality. Eligible studies were randomized controlled trials of CRT-D for the treatment of CHF. Eligible studies reported all cause deaths as outcomes. Seven randomized trials were included in the meta-analysis, comparing CRT-D with no-CRT-D. The outcome was all cause mortality.ResultsA total of 747 events occurred in 4531 patients from seven randomized trials. Follow-up in the included trials ranged from 6 to 69 months. Most trials were high-quality. Pooled analysis demonstrated CRT-D significantly reduced all cause mortality (odds ratios (OR) 0.55, 95% confidence interval 0.40 to 0.76, P = 0.0002). Subgroup analysis CRT-D vs CRT alone and CRT-D vs medical therapy alone, significantly reduced all cause mortality (OR 0.48, 95% confidence interval 0.31 to 0.75, P = 0.001; OR 0.64, 95% confidence interval 0.46 to 0.90, P = 0.009; respectively).ConclusionsCRT-D significantly reduces all cause mortality in patients with advanced CHF.