Endometriosis and irritable bowel syndrome: a systematic review and meta-analysis

Purpose: Irritable bowel disease and endometriosis are two common diseases characterized by chronic inflammation state and recurrent abdominal pain. As a consequence of sharing of symptoms and chronic inflammation, endometriosis and IBS may coexist and be misdiagnosed and this leads to delays in diagnosis, mismanagement, and unnecessary testing. In recent years, some studies have found higher risk of IBS in women with endometriosis, compared to women without endometriosis. To provide a general overview, we performed a systematic review and a meta-analysis on published data on this issue. Methods: By a systematic literature search selection process, 11 studies were identified for the current study: 2 prospective and 2 retrospective cohort studies, 4 case-control studies, 1 cross-sectional study and 2 clinical series. Results: When we meta-analysed data about the prevalence of IBS in women with endometriosis, the overall OR (95%CI), compared to women without endometriosis was 3.26 (1.97-5.39) with no statistically significant heterogeneity. All three studies considering the incidence of IBS in women with a previous diagnosis of endometriosis showed about twofold greater risk among women with endometriosis than women without. Likewise, in the random effects model of the meta-analysis, the overall OR of history of IBS in women with endometriosis was 3.10 (95% CI 2.06-4.67), with no heterogeneity between three studies considered. Conclusion: This meta-analysis provides epidemiological evidence of a link between endometriosis and IBS, highlighting two or more times higher risk of IBS in women with endometriosis compared to women without the condition.