Obsessive-compulsive disorder and the associated risk of autoimmune skin diseases: A nationwide population-based cohort study

Background: The concurrent incidence of autoimmune comorbidities in obsessive-compulsive disorder (OCD) is known. However, the association between OCD and related autoimmune skin diseases (ASDs) has not been well studied. Objective: This study aimed to investigate the association between OCD and the risk of ASDs. Methods: To assess the risk of developing ASDs, we recruited 44,324 patients with OCD and 177296 matched controls from the National Health Insurance Research Database in Taiwan. A Cox regression model was used for the analyses. Results: After adjusting for confounders, an increased risk of ASDs among the patients with OCD (adjusted hazard ratio [aHR], 6.36; 95% confidence interval [CI], 5.43-7.45) was found when compared to the controls. Statistically significant associations were found between OCD and seven individual ASDs, including psoriasis (aHR, 12.52; 95% CI, 8.78-17.85), lichen planus (aHR, 27.22; 95% CI, 13.09-56.60), alopecia areata (aHR, 13.69; 95% CI, 9.38-19.98), autoimmune bullous diseases (aHR, 4.30; 95% CI, 2.03-9.11), hidradenitis suppurativa (aHR, 29.95; 95% CI, 3.35-267.62), vitiligo (aHR, 9.35; 95% CI, 5.35-16.32), and lupus erythematosus (aHR, 2.10; 95% CI, 1.52-2.91). Conclusions: Patients with OCD had an increased risk of developing ASDs compared to matched controls. Further studies are required to clarify the underlying mechanisms.