Comparative analysis of the risk of severe bacterial infection and septicemia in adolescents and young adults with treatment-resistant depression and treatment-responsive depression - a nationwide cohort study in Taiwan.

Previous studies have shown an association between depression and increased susceptibility to infection in the general population. However, there has been no prior research specifically examining the relationship between treatment-resistant depression (TRD) and severe bacterial infections (SBI) in adolescents and young adults. This retrospective observational cohort study utilized the Taiwan National Health Insurance Research Database (NHIRD) from 2001 to 2010. It included adolescents (12-19 years of age) and young adults (20-29 years of age) diagnosed with major depressive disorder (MDD), comprising 6958 cases of TRD and 27,832 cases of antidepressant-responsive depression (ARPD). The TRD and ARPD groups were further matched (4:1) by chronological age, age at diagnosis of depression, sex, residence, and family income. The primary outcomes were severe bacterial infections (SBI) and septicemia. Cox regression analysis was conducted to identify the risk of hospitalization due to SBI or septicemia during the follow-up period. Compared with controls, the ARPD group had increased risks of SBI (hazard ratio [HR] with 95% confidence interval [CI]: 3.90, 2.73-5.57) and septicemia (HR, 95% CI: 2.56, 1.34-4.91). Notably, the risks of SBI and septicemia appeared to be further elevated in the TRD group. The TRD group exhibited higher incidences of SBI (HR, 95% CI: 6.99, 4.73-10.34) and septicemia (HR, 95% CI: 2.85, 1.28-6.36) than the control group. Adolescents and young adults with TRD had 6.99-fold and 3.90-fold increased risks of SBI and septicemia compared to individuals without MDD, respectively. Therefore, healthcare providers need to be vigilant when monitoring and implementing preventive measures in this population.