Impact of Endometriosis on the Progression of Inflammatory Bowel Diseases: A Multicenter Retrospective Study

Introduction: Women with endometriosis have a higher risk of developing inflammatory bowel diseases (IBD). This study aimed to better understanding the impact of endometriosis on the course of IBD. Methods: We conducted a retrospective cohort study in 18 French and Belgian IBD centers between June 2022 and March 2023. Any patient with both conditions was eligible for inclusion. They were randomly matched to 1 or 2 patients with IBD without endometriosis. The impact on IBD progression was assessed using a composite severity criterion including intestinal damage or need for bowel surgery. Results: Overall, 207 patients with both conditions (149 Crohn's disease (CD); 58 ulcerative colitis (UC)) were matched to 409 patients with IBD alone. The median follow-up duration for IBD was 10 years [5.75-17]. No difference was observed between the two groups regarding CD location, disease phenotype, and anoperineal involvement. Proctitis were more frequent in patients with UC and endometriosis. IBD patients with endometriosis were significantly less exposed to immunosuppressants (UC p<0.01; CD p<0.001) and biologics (UC p<0.01; CD p<0.001). CD patients with endometriosis had a less severe disease course compared to patients without endometriosis (HR=0.68; 95%CI 0.50-0.92; p=0.011). UC patients with endometriosis had not a significant different disease course compared to patients without endometriosis (HR=1.73; 95%CI 0.74-4.00; p=0.20). These results were similar in the subgroup of patients with endometriosis treated surgically. Conclusions: Endometriosis does not negatively influence the course of IBD, patients with CD even have a less severe progression. Patients were significantly less exposed to immunosuppressants and biologics.