Studies on colonoscopy and inflammatory conditions of the colon

Abstract: Background: Colonoscopy is a key investigative tool in inflammatory bowel disease and diverticular disease, but elements of the pathogenesis, symptomatology and safety of procedures in these two conditions remain unknown. The best surveillance method for colorectal cancer in inflammatory bowel disease (IBD) is debated. Chromoendoscopy (CE) is recommended, but whether CE is the best method in high-definition (HD) colonoscopy is unclear. IBD causes inflammation and sometimes fibrosis in the colon that might lead to a more fragile colon. Whether this is linked to a higher rate of adverse events in colonoscopy is unknown. The cause of diverticular disease is mostly unknown. One plausible cause is difference in microbiota composition, but studies are limited. Pain and other symptoms are not well documented in uncomplicated diverticulosis and studies are scarce. Methods and Main results: Paper I: A randomized study of IBD-patients undergoing surveillance colonoscopy comparing HD-CE with random biopsies vs HD-White Light Endoscopy (WLE) with random biopsies. Three hundred and five patients were included (n = 152, HD-CE; n = 153, HD-WLE). Dysplastic lesions were found in 17 individuals with HDCE and 7 individuals with HD-WLE (p = 0.032). The number of dysplastic lesions found for every 10 minutes of withdrawal time was 0.066 with HD-CE and 0.027 with HD-WLE (p = 0.056). Paper II: A nationwide, population-based register study in Sweden examining all colonoscopies between 2003 and 2019. The association between IBD and other risk factors with increased bleeding or perforation rates in colonoscopy was assessed. All incidents of bleeding and perforation within 30 days after each colonoscopy were recorded. Bleeding (0.19%) and perforation (0.11%) were found to be rare. Bleeding (OR 0.66, p < 0.001) and perforation (OR 0.79, p < 0.033) were less common in colonoscopies on individuals with IBD. Paper III: An investigation of faecal and mucosal microbiota composition in a nested casecontrol study from the Swedish POPCOL study at the faecal and mucosa-associated microbiota composition in individuals with and without diverticulosis and in addition, between individuals 2 who later developed diverticulitis compared with those that did not. No difference in microbiota richness or diversity was detected in either analysis. There was no different in taxonomic composition in the diverticulosis analysis, but those that later developed acute diverticulitis had higher abundance of genus Comamonas. Paper IV: An analysis of abdominal symptom diaries from the Swedish POPCOL study, focussing on the frequency, severity and location of abdominal pain as well as the association with IBS in those with and without diverticulosis. Diverticulosis was not associated with more abdominal pain nor was it associated with more left lower quadrant (LLQ) pain. Conclusions: These data indicate that in IBD patients, HD-CE is superior to HD-WLE endoscopy in finding dysplastic lesions per colonoscopy as well as more efficient per 10 minutes of withdrawal time. We recommend the use of HD-CE in surveillance of IBD patients. Individuals with IBD did not experience more adverse events compared with individuals without IBD. This implies that no special considerations need to be taken when performing colonoscopy on individuals with IBD. There was no sign of difference in microbiota composition when comparing individuals with and without diverticulosis. Individuals that later developed acute diverticulitis had a higher abundance of genus Comamonas but the significance of this is unclear and may suggest a limited role for microbiota in the pathogenesis of diverticular disease. Diverticulosis was not associated with more abdominal pain or more LLQ abdominal pain when compared to individuals without diverticulosis. Abdominal pain was strongly associated with a diagnosis of IBS.