Risk of autoimmune diseases after post-traumatic stress disorder: a nationwide cohort study

This longitudinal study aimed to investigate the risk of subsequent autoimmune disease in patients with post-traumatic stress disorder (PTSD) in Asian population. Between 2002 and 2009, we enrolled 5273 patients with PTSD and 1:4 matched controls from the National Health Insurance Database of Taiwan, and followed up the patients until December 31, 2011, or death. The investigated autoimmune diseases included thyroiditis, lupus, rheumatic arthritis, inflammatory bowel disease, Sjogren's syndrome, dermatomyositis, and polymyositis. The Cox regression model was used to estimate the risk of developing autoimmune diseases, with adjustment for demographics and psychiatric and medical comorbidities. Furthermore, we examined the psychiatric clinics utility of patients with PTSD indicating the severity of PTSD in association with autoimmune diseases. After adjusting for confounders, patients with PTSD had a 2.26-fold higher risk of developing any autoimmune diseases (reported as hazard ratios with 95% confidence intervals: 1.82-2.80) than the controls. For specific autoimmune diseases, patients with PTSD had a 2.70-fold higher risk (1.98-3.68) of thyroiditis, a 2.95-fold higher risk (1.20-7.30) of lupus, and a 6.32-fold higher risk (3.44-11.60) of Sjogren's syndrome. Moreover, the PTSD severity was associated with the risk of autoimmune diseases in a dose-dependent manner. The patient with the highest psychiatric clinics utility was associated with an 8.23-fold higher risk (6.21-10.90) of any autoimmune diseases than the controls. Patients with PTSD had an increased risk of autoimmune diseases, and such risk was associated with the severity of PTSD in a dose-dependent manner. However, the present study did not provide a direct effect between PTSD and autoimmune diseases, but rather an association. Further studies are warranted to examine the underlying pathophysiological mechanisms.