Bidirectional interaction between implantable cardioverter-defibrillator therapy and mental disorders: nationwide cohort study

Abstract Background and Aims The bidirectional relationship between implantable cardioverter-defibrillator (ICD) therapy and mental disorders remains underexplored. This study evaluated this relationship using a nationwide cohort. Methods From the Korean National Health Insurance Service database, 6,356 patients undergoing ICD implantation and 17,644 propensity score-matched individuals were selected between 2010 and 2020, using a sequential target trial emulation approach, simulating a randomized controlled trial and adjusting for immortal-time bias. In the ICD group, long-term prognosis was compared between patients with and without new-onset mental disorders post-implantation, treating the time to mental disorder onset as a time-varying covariate. Results The 10-year cumulative incidence of new-onset mental disorders was 37.3% in ICD patients, significantly higher than in the matched general population (HR 1.21, 95% CI 1.14–1.29). The most frequent mental disorders were depressive disorder (18.4%), insomnia (16.8%), and anxiety disorder (5.8%). Subsequently, among ICD patients, the development of new-onset mental disorders adversely affected the long-term prognosis, with significantly higher 10-year cumulative all-cause mortality (HR 2.03, 95% CI 1.79–2.32), cardiac mortality (HR 1.88, 95% CI 1.58–2.25), severe heart failure events (HR 2.22, 95% CI 1.61–3.05), and any-cause readmission (HR 1.67, 95% CI 1.52–1.83) compared to those without mental disorders. Particularly, the occurrence of schizophrenia spectrum disorder and early-onset mental disorders (within 3 years post-implantation) were strongly associated with worse long-term clinical outcomes. Conclusions Evidence-based ICD implantation, proactive screening, and timely management of new-onset mental disorders may mitigate adverse outcomes in ICD patients, given the bidirectional relationship between ICD therapy and mental health.