Objectives To investigate the potential association between uveitis and an increased risk of developing inflammatory bowel disease (IBD). Methods We conducted a retrospective cohort study by interrogating data from the Taiwan National Health Insurance Research Database entered between January 1, 2001 and December 31, 2013 to identify uveitis patients and age- and gender-matched controls. The cumulative incidence rates of subsequent IBD in the two groups were compared. The adjusted hazard ratio (HR) of IBD related to uveitis was generated by a multivariate cox regression model after adjustment for hypertension, diabetes, hyperlipidaemia, obesity and smoking. Furthermore, the HRs of the Crohn's disease (CD) and ulcerative colitis (UC) IBD subtypes were calculated separately. Results A total of 198,923 subjects with uveitis and 397,846 controls were enroled. The mean age of the cohort was 47.7 +/- 18.9 years. A significantly higher cumulative incidence of IBD was found in the uveitis group than in controls (4.13% vs. 1.48%, p < 0.0001). Under univariate cox regression analysis, uveitis patients had a significantly higher risk of IBD (HR = 1.47; 95% confidence interval (CI): 1.43-1.52, p < 0.0001). The association remained significant in the multivariate regression model, with an adjusted HR of 1.44 (95% CI: 1.39-1.49, p < 0.0001). Moreover, in subgroup analysis, uveitis was significantly associated with an increased risk of Crohn's disease (adjusted HR = 1.49; 95% CI: 1.44-1.54), but not with ulcerative colitis (adjusted HR = 1.03; 95% CI: 0.92-1.15). Conclusions Patients with uveitis are at significantly greater risk of developing IBD than individuals without uveitis.
