Suicide mortality after severe autoimmune disease: A nationwide population-based study

Previous studies reported higher suicide mortality in severe autoimmune diseases (SADs). However, few studies have comprehensively assessed the suicide mortality and accidental mortality across different types of SADs and their associations with comorbid psychiatric disorders.

We utilised the nationwide database of Taiwan from 2003 to 2017, linked with the National Death Registry, to identify 1,164,960 individuals, including 232,992 patients with SADs and 931,968 matched controls. Cox-regression was used to estimate the risks of suicide and accidental mortalities. Subgroup analyses were conducted based on sex, ten specific SAD types, and eight psychiatric comorbidities.

Patients with SAD had a 1.54-fold increased risk of suicide mortality (hazard ratio [HR]: 1.54, 95% confidence interval [CI]: 1.36-1.74) compared to controls. Specifically, individuals with systemic lupus erythematosus (2.04; 1.47-2.83), rheumatoid arthritis (1.57; 1.25-1.96), and Sjögren's syndrome (2.32; 1.69-3.18) exhibited higher suicide mortality compared to the controls. The suicide mortality was further higher among SAD individuals with psychiatric comorbidities, including schizophrenia (2.82; 1.94-4.10), major depressive disorder (4.44; 3.79-5.20), and substance use disorder (2.59; 1.74-3.87). Among female patients, comorbid major depressive disorder (5.15; 4.16-6.39), alcohol use disorder (5.17; 2.61-10.24), and substance use disorder (4.50; 2.53-7.99) showed approximately 5-fold increased risk of suicide mortality compared to the controls.

These findings suggest that patients with SADs are at significantly higher risk of suicide, particularly when psychiatric disorders are present. Routine mental health screening and integrated care may be critical in reducing suicide risk in this vulnerable population.