Disparities in Referral and Utilization of Implantable Cardioverter-Defibrillators for Primary Prevention of Sudden Cardiac Death

BACKGROUND: Implantable cardioverter-defibrillators (ICDs) reduce mortality in patients with reduced left ventricular ejection fraction (LVEF). We investigated sex disparities in a contemporary Canadian population for utilization of primary prevention ICDs. METHODS: This was a retrospective cohort study on patients with reduced LVEF admitted to hospitals from 2010 to 2020 in Nova Scotia (population = 971,935). RESULTS: There were 4406 patients eligible for ICDs: 3108 (71%) men and 1298 (29%) women. The mean follow-up time was 3.9 ± 3.0 years. Rates of coronary disease were similar between men and women (45.8% vs 44.0%; P = 0.28), but men had lower LVEF (26.6 ± 5.9% vs 27.2 ± 5.8%; P = 0.0017). The referral rate for ICD was 11% (n = 487), with 13% of men (n = 403) and 6.5% of women (n = 84) referred (P < 0.001). The ICD implantation rate in the population was 8% (n = 358), with 9.5% of men (n = 296) and 4.8% of women (n = 62) (P < 0.001) receiving the device. Men were more likely than women to receive an ICD (odds ratio 2.08, 95% confidence interval 1.61-2.70; P < 0.0001)). There was no significant difference in mortality between men and women (P = 0.2764). There was no significant difference in device therapies between men and women (43.8% vs 31.1%; P = 0.0685). CONCLUSIONS: A significant disparity exists in the utilization of primary prevention ICDs between men and women in a contemporary Canadian population.