POSC36 Implantable Cardiac Defibrillators in Heart Failure Patients: An Overview of Reviews and Meta-Analysis


      Due to the new European Medical Device Regulations, a high-quality synthesis of clinical evidence becomes important, especially for implantable digital biomarkers. Several systematic reviews (SRs) synthesized the evidence on the efficacy of implantable cardiac defibrillators (ICDs) in chronic heart failure. Our aim was to provide an overview of published systematic reviews.


      A comprehensive search was performed using two different search strategies (one using keywords from the definition of digital biomarkers, another using keywords related to defibrillators) in PubMed, Cochrane Library and Dare, limited to the years 2010-2020. SRs performing meta-analysis of the effect of ICDs compared with all other non-defibrillator comparator on all-cause mortality in patients with heart failure were identified by two reviewers. The quality of the studies was assessed using the AMSTAR-2 tool. A random-effect meta-analysis of log hazard ratio was performed. We assessed the quality of evidence using the GRADE tool.


      Nine SRs were identified. Four eligible SRs had critically low methodological quality, three had low quality and only two SRs had high quality. Meta-analysis was performed on 25 randomized controlled trials involving 8,603 and 32,928 patients in intervention and control groups, respectively. There was a significant difference in all-cause mortality between the two arms (log hazard ratio= -0.23, 95% CI (-0.328 to -0.125), heterogeneity I2= 65.76%, p-value<0.001). The proposed evidence is of overall moderate quality.


      The current meta-analysis of available randomized evidence suggests that the use of ICD therapy should have a beneficial effect on reducing all-cause mortality in patients with heart failure. However, the moderate quality of the current evidence should be considered, as less than 75% of the included studies have low risk of bias.