The Association Between Inflammatory Bowel Disease and Colonic Diverticulosis

Abstract

Introduction: The wide prevalence of diverticulosis in the Western population is thought to be secondary to the effect of diet1. There have been 2 studies, on study subjects outside the United States that have documented the lower prevalence of diverticulosis in ulcerative colitis(UC) and IBD respectively 1-3. Given the high prevalence4 of diverticular disease in the US population, our goal was to re-examine the association of colonic diverticulosis in people with IBD and investigate any differences between Crohn's disease and UC. Methods: A total of 8195 patients underwent colonoscopy between 2006 - 2013. Out of these, 230 patients underwent a colonoscopy for a pre-existing diagnosis of inflammatory bowel disease, with 118 Crohn's disease and 112 UC patients. We compared these patients to 446 age and sex matched controls. Results: There was a significant difference between the prevalence of diverticulosis in patients with or without IBD, with only 11 % (27) of the IBD group and 48 % (243) of the non IBD group being diagnosed with diverticulosis, suggesting that IBD has a protective effect on diverticulosis (OR 0.149, P0.000 95% CI 0.092-0.2355). In a comparison between the prevalence of diverticulosis in Crohn's (19 patients) vs UC (8 patients), we found that patients with Crohn's disease were 2.5 times more likely to have diverticulosis as compared to patient with UC (OR 2.49 P 0.0349, 95% CI 0.984-6.876). Patients with diverticulosis were 4 times more likely to have Crohn's disease that included the sigmoid colon. (OR 4.6, P0.0009, 95% CI 1.5005-13.065). Conclusion: Our results provide validity for previous clinical observations noting decreased overall prevalence of diverticulosis in IBD. It noted a remarkable difference between the prevalence of diverticulosis in Crohn's vs ulcerative colitis, being 2.5 times lower in patients with ulcerative colitis as compares to Crohn's disease. The association of sigmoid diverticulosis and Crohn's disease has been previously reported in various studies6-9, with limited inflammation of the sigmoid colon suggesting segmental colitis associated with diverticulosis (SCAD). In our study population, 8 out of 19 patients with Crohn's and diverticulosis actually presented with isolated sigmoid inflammation, which is a relatively uncommon entity. More prospective studies need to be performed, especially to follow up the natural history of progression of patients with a diagnosis of SCAD.Table 1: Association of diverticulosis with IBDTable 2: Association of diverticulosis with Crohn's disease