Tuberculosis in Patients With Chronic Mental Illness

Patients with mental illness were found to have a significantly higher risk of developing tuberculosis (TB). To investigate this association, this study utilized the National Health Insurance Research Database (NHIRD), a nationally representative dataset in Taiwan, to assess TB incidence among patients with chronic psychiatric disorders—including schizophrenia, bipolar disorder, schizoaffective disorder, and major depressive disorder—compared to the general population. Patients diagnosed between 2002 and 2013 were identified through the Catastrophic Illness Registry, which ensures strict clinical verification and captures only severe and persistent mental illness cases. After excluding individuals with conditions such as type 1 diabetes, cirrhosis, cancer, dialysis, HIV, past TB, and amended diagnoses, a total of 162,377 subjects were included in the analysis. TB cases were defined using the Tuberculosis Database, which requires positive culture results, radiographic abnormalities, and diagnostic confirmation.

The study population consisted of 162,161 mental illness patients and 810,805 matched controls, with no significant baseline differences in sex, age, income, urbanization level, comorbidity index, or major comorbidities, confirming effective propensity score matching. Results showed consistently higher TB incidence in mental illness patients overall (87 vs. 71 per 100,000 person-years), across both sexes, and most age groups. The difference was particularly pronounced in those aged 65 years or older (278 vs. 195). TB incidence was also higher across nearly all income levels and urbanization strata, except for rural towns where rates were slightly lower in patients with mental illness. Importantly, the elevated TB incidence was observed regardless of the presence of type 2 diabetes mellitus or chronic kidney disease.

After adjusting for confounding variables, the conditional Cox proportional hazards model confirmed a 1.48-fold increased risk of TB among patients with mental illness (95% CI: 1.38–1.59). Additional risk factors included older age, which showed a steep increase in hazard ratios (HRs ranging from 1.86 for ages 20–34 to 21.82 for ≥65 relative to <20), and lower income, which was inversely associated with TB risk. Comorbidities such as type 2 diabetes (HR: 1.22) and chronic kidney disease (HR: 1.24) further heightened susceptibility. Cumulative incidence curves demonstrated a persistently higher rate of TB in the mental illness group compared with the general population, underscoring the need for targeted TB screening and preventive strategies for this vulnerable population.

Source: Hung, L.C., Kung, P.T., Tsai, T.H., Tsai, W.C. and Huang, K.H., 2025. Risk Assessment of Tuberculosis in Patients With Chronic Mental Illness and Related Factors: A Population‐Based Cohort Study in Taiwan. The Clinical Respiratory Journal, 19(6), p.e70088.