Impact of Concomitant Endometriosis on Phenotype and Natural History of Inflammatory Bowel Disease

Background: Inflammatory bowel disease (IBD) and endometriosis are immune-mediated chronic inflammatory disorders affecting young women. The clinical significance of concomitant endometriosis on the course of IBD has not been previously studied. The aim of this study was to determine whether women with concomitant endometriosis and IBD have a unique phenotype and worse prognosis of IBD. Methods: This was a case-control study performed at a tertiary referral center. Cases were women with diagnoses of both endometriosis and IBD. Two random IBD controls without endometriosis were selected for each case, frequency matched for age and IBD type, Crohn's disease (CD) or ulcerative colitis. Primary outcomes included disease phenotype; the use of immunomodulators, antiTNF agents, or combination therapy and the need for IBD-related surgery. Results: We identified 51 cases with endometriosis and IBD (28 CD, 23 ulcerative colitis). There was no difference in race, age at IBD diagnosis, and mean duration of IBD between endometriosis-IBD cases and controls. Among endometriosis-CD patients whose endometriosis was surgically verified, there was a higher risk for stricturing disease compared with CD controls (odds ratio, 11.8; 95% confidence interval, 2.03-69.0). There was no difference in phenotype in endometriosis-ulcerative colitis patients. There were no significant differences in IBD-related medication use or surgeries overall or when stratified by IBD type. Conclusions: Patients with CD and endometriosis, which was surgically diagnosed, were more likely to have stricturing CD. Concomitant endometriosis did not impact the natural history of IBD.