Sex, Race and Age Differences of Cardiovascular Outcomes in Implantable Cardioverter-Defibrillator RCTs: A Systematic Review and Meta-Analysis

Abstract Background Limited data exists regarding the use of implantable cardioverter-defibrillators (ICDs) in diverse populations. This study explores cardiovascular (CV) outcomes and mortality from ICD randomized controlled trials (RCTs) by sex, race and age. Methods Five electronic databases (PubMed, Emcare, Embase, Medline and CINAHL) were searched from inception to July 12, 2021 for RCTs of ICD therapy in adult patients. Data was analyzed for clinical outcomes including all-cause or CV death and heart failure hospitalization (HFH). Results Among five RCTs (mean age 63 years, 78% male, 76% White) with moderate overall risk of bias, clinical outcomes in ICD patients (n=3260) versus a control group (n=3685) were compared. No between-group sex differences were observed for all-cause death (odds ratio (OR) 0.86, p=0.51), CV death (OR 0.98, p=0.96), HFH (OR 0.95, p=0.87), or HFH and all-cause death (OR 0.83, p=0.51) in the ICD group when comparing male versus female sex. All-cause death (OR 1.20, p=0.67) did not differ between White versus Black patients with ICD therapy. Outcomes data for other non-White, non-Black race groups were often unreported. Most RCTs originated in North America, had male leadership, and were evenly sponsored by industry or peer-reviewed funding. Conclusion There is a paucity of outcomes data by sex, race and age in current RCTs evaluating ICD therapy. While ICD patient outcomes did not significantly differ by sex or race, improved data analyses and reporting are needed to determine the relationship between these sociocultural factors and clinical outcomes among distinct ICD patient cohorts.