Sex, Race, and Age Differences in Cardiovascular Outcomes in Implantable Cardioverter–Defibrillator Randomized Controlled Trials: A Systematic Review and Meta-analysis

BACKGROUND: Data are limited 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 Cumulative Index to Nursing & Allied Health Literature CINAHL) were searched for dates from their inception to July 12, 2021, for RCTs of ICD therapy in adult patients. Data were analyzed for clinical outcomes, including all-cause or CV death, and heart failure hospitalization (HFH). RESULTS: Among 5 RCTs (mean age: 63 years; 78% male; 76% White) with moderate overall risk of bias, clinical outcomes in patients with an ICD (n = 3260) vs 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, in a comparison of male vs female sex. All-cause death (OR 1.20, P = 0.67) did not differ for White vs Black patients receiving 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 vs peer-reviewed funding. CONCLUSIONS: Outcomes data are sparse, by sex, race, and age, in current RCTs evaluating ICD therapy. Although 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.