Sex Differences in Implantation and Outcomes of Cardiac Resynchronization Therapy in Real World Settings: A Systematic Review of Cohort Studies

Abstract Background There is conflicting evidence from randomized trials on the effects of Cardiac Resynchronization Therapy (CRT) by sex and differences in access are unknown. We examined sex differences in the implantation rates and outcomes in patients treated with CRT using cohort studies. Methods We followed a pre-specified protocol (PROSPERO: CRD42020204804). MEDLINE, EMBASE and Web of Science were searched for cohort studies that evaluated the response to CRT in patients ≥18 years old and reported sex-specific information in all languages from January 2000 to June 2020. Results We included 97 studies (1,172,654 men and 486,553 women). Men received CRT more frequently than women (Median ratio, 3.16, 25th to 75th IQR, 2.48-3.62). In the unadjusted analysis, men had a greater long-term all-cause mortality rate after CRT compared with women (hazard ratio [HR], 1.50; 95% CI, 1.38-1.63 [P Conclusions We found in this large meta-analysis that men were more often implanted with CRT than women, yet men had a higher long-term all-cause mortality following CRT compared to women and smaller improvement in LVEF. Reasons for this difference in implantation rates of CRT in real world practice need to be investigated.