Mortality and Lithium-Protective Effects after First-Episode Mania Diagnosis in Bipolar Disorder: A Nationwide Retrospective Cohort Study in Taiwan

Abstract

<b><i>Introduction:</i></b> This study aimed to estimate all-cause mortality in patients after a first-episode mania (FEM) and examine whether six guideline-recommended medications can reduce mortality. <b><i>Methods:</i></b> The cohort included population-based FEM samples and matched controls from Taiwan, spanning 2007 to 2018. The primary outcomes assessed were all-cause/suicide-related mortality, while the secondary outcome focused on mortality associated with pharmacological treatments. We compared mortality in post-FEM patients and age-/sex-matched controls without any diagnosed bipolar disorders and patients with and without psychopharmacological treatment using Cox regression analysis, respectively. Statistics were presented with time-to-event adjusted hazard ratios (AHRs) and 95% confidence intervals (CIs). <b><i>Results:</i></b> The study included 54,092 post-FEM patients and 270,460 controls, totaling 2,467,417 person-years of follow-up. Post-FEM patients had higher risks of all-cause mortality (AHR 2.38, 95% CI: 2.31–2.45) and suicide death (10.80, 5.88–19.84) than controls. Lithium (0.62, 0.55–0.70), divalproex (0.89, 0.83–0.95), and aripiprazole (0.81, 0.66–1.00) were associated with reduced all-cause mortality compared to non-users. There were no significant all-cause mortality differences for quetiapine (0.95, 0.89–1.01), risperidone (0.92, 0.82–1.02), and paliperidone (1.24, 0.88–1.76) users. When accounting for drug action onset times in sensitivity analyses, only lithium significantly reduced all-cause mortality (AHR range 0.65–0.72). There were 35 and 16 suicide deaths in post-FEM patients and controls, respectively. No drug had a significant effect on suicide deaths (lithium: 6; divalproex: 7; aripiprazole: 0; quetiapine: 10; risperidone: 4; paliperidone: 1). <b><i>Conclusion:</i></b> Post-FEM patients had a higher risk of all-cause/suicide-related mortality, and lithium treatment might reduce all-cause mortality.