Study Design and Cohort Description of DEFIB-WOMEN: A National Danish Study in Patients with an ICD

Little systematic evidence is available on potential gender differences in patients with an implantable cardioverter defibrillator (ICD) from a real-world cohort. We designed the DEFIB-WOMEN (The Utilization of Implantable Cardioverter DEFIBrillator Therapy in the Treatment of Heart Disease: Clinical and Psychological outcomes in WOMEN) study to examine gender differences on (1) patient-reported outcomes (PROs), (2) procedure- and device-related complications, and (3) ventricular tachyarrhythmia and mortality. This presents the study design and baseline characteristics of the cohort.

DEFIB-WOMEN is a national, multicenter, prospective, observational study. First-time implanted patients are asked to complete PROs at several time points. Information on baseline and follow-up characteristics are captured from patients' medical records, purpose-designed questions, and the Danish national registers. The DEFIB-WOMEN cohort is composed of 1,790 (19% women; 343/1,790) patients implanted between June 2010 and April 2013.

Women and men differed on several demographic and clinical baseline characteristics, including on the prescription of β-blockers, statins, angiotensin-converting enzyme inhibitors, and psychotropic agents. Although women generally had a healthier clinical profile, they reported significantly more symptoms of anxiety and depression and ICD concerns (fear of shock) as compared to men. These differences were not only statistically significant but also clinically relevant, with the magnitude of the differences in anxiety and ICD concerns being 0.44 and 0.42, respectively, as indicated by Cohen's effect size index.

These preliminary results indicate that women with an ICD experience particularly more anxiety and ICD concerns as compared to men at the time of implant. Future results of DEFIB-WOMEN will show whether these gender differences persist and whether there are also gender differences in complications and survival.