Association between a history of mental illness and the risk of systemic autoimmune rheumatic diseases: a nationwide, population-based case-control study.

OBJECTIVE

Patients with systemic autoimmune rheumatic diseases (SARD) are at risk of mental illness, but whether mental illnesses are risk factors for SARD, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Sjögren's syndrome (SS), systemic sclerosis (SSc), dermatomyositis (DM)/polymyositis (PM), are still unknown. Therefore, we aim to address the association between a history of mental illnesses and the risk of SARD using a population-based database.

METHODS

We used the 2000-2020 Taiwanese National Health Insurance Research Database in this case-control study. Multivariable logistic regression was conducted to estimate the adjusted odds ratios (aORs) with 95% confidence interval (CIs). Sensitivity analyses were conducted using distinct definitions of mental illnesses and wash-out periods.

RESULTS

A total of 77,848 SARD cases and 313,392 age- and sex-matched non-SARD controls (1:4) were included for analyses. Patients with SARD were more likely to have history of mental illness (39.8% vs. 27.0%, p < 0.001). After adjusting for potential confounders, we found significant associations of between a history of mental illnesses with SARD (aOR, 1.65, 95%CI, 1.62-1.68), RA (aOR, 1.28, 95% CI, 1.24-1.32), SLE (aOR, 1.62, 95% CI, 1.54-1.71), SS (aOR, 2.35, 95% CI, 2.28-2.42), SSc (aOR, 1.40, 95% CI, 1.24-1.58), and DM/PM (aOR, 1.18, 95% CI, 1.05-1.32). The results remained robust after using various definitions of mental illnesses and wash-out periods.

CONCLUSION

We found that a history of mental illnesses was significantly associated with incident SARD, and the strength of association tended to be strong in patients with SS, followed by SLE. More studies are warranted to clarify the underlying mechanism. Key Points • Patients with systemic autoimmune rheumatic diseases (SARD) are at risk of mental illness, but whether mental illnesses are risk factors for SARD are still unknown. • We used a population-based database to demonstrate that mental illness was associated with the risk of SARD, particularly Sjögren's syndrome and systemic lupus erythematosus. • These findings underscore the importance of integrated care approaches, including surveys for autoimmune diseases, among patients with mental illness.