Published online Jul 16, 2019. doi: 10.4253/wjge.v11.i7.427
Peer-review started: May 10, 2019
First decision: May 31, 2019
Revised: June 7, 2019
Accepted: June 20, 2019
Article in press: June 21, 2019
Published online: July 16, 2019
Processing time: 72 Days and 11.4 Hours
The current guidelines suggest that patients should undergo endoscopic evaluation of the colonic lumen after an episode of computed tomography (CT) proven acute diverticulitis to rule out malignancy. However, with the advancement and evolution of CT scan technology, the necessity for routine colonoscopy post episode of acute diverticulitis has become questionable.
Colonoscopy is invasive and is associated with discomfort, particularly in patients with diverticular disease. Patients with diverticular disease also have more difficult endoscopic procedures, and have a higher risk of perforation. Cost-effectiveness of investigating all patients also remains unclear. For this reason, this project has set out to establish whether routine colonoscopy should be offered to patients after an episode of acute diverticulitis.
The main objective of this research was to establish whether there was any added benefit to offering patients routine colonoscopy after every episode of acute diverticulitis. The significance of demonstrating that colonoscopy may in fact not be required routinely would be two-fold. It would allow for a reduction in number of colonoscopy related complications including discomfort, bleeding and perforation, as well as a significant reduction in overall costs, and financial burden.
We conducted a retrospective cohort study in three centres in the north west of England. The study group included consecutive patients who were admitted to our trust with an episode of acute diverticulitis over a three-year period between January 2014 and December 2016. The control group included all patients who had undergone a one-off screening flexible sigmoidoscopy at the age of fifty-five, as part of the National Bowel Cancer Screening Programme over a fourteen-month period between October 2015 and December 2016. Three independent authors collected the data using a data collection proforma. We considered the total number of adenomas, non-advanced adenomas, and advanced adenomas as primary outcome measures. The secondary outcomes included low-risk adenomas, intermediate-risk adenomas, high-risk adenomas, invasive cancers, total number of polyps, and hyperplastic polyps. We also performed a systematic review according to an agreed predefined protocol and we were compliant with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement standards. We calculated the risk difference (RD) as the summary measure. Heterogeneity among the studies was assessed using the Cochrane Q test (χ2). Random or fixed effects modelling were used as appropriate for analysis; random effects models were used if considerable heterogeneity was found among the studies. The results were reported in a forest plot with 95% confidence intervals (CIs). We used the Review Manager 5.3 software for data synthesis.
Overall, 68 and 1309 patients were included in the diverticulitis and control groups respectively. There was no difference in the risk of adenomas (5.9% vs 7.6%, P = 0.59), non-advanced adenomas (5.9% vs 6.9%, P = 0.75), advanced adenomas (0% vs 0.8%, P = 1), cancer (0% vs 0.15%, P = 1.00), and polyps (16.2% vs 14.2%, P = 0.65) between both groups. Meta-analysis of data from 4 retrospective observational studies, enrolling 4459 patients, showed no difference between the groups in terms of risk of adenomas (RD = -0.05, 95%CI: -0.11, 0.01, P = 0.10), non-advanced adenomas (RD = -0.02, 95%CI: -0.08, 0.04, P = 0.44), advanced adenomas (RD = -0.01, 95%CI: -0.04, 0.02, P = 0.36), cancer (RD = 0.01, 95%CI: -0.01, 0.03, P = 0.32), and polyps (RD = -0.05, 95%CI: -0.12, 0.02, P = 0.18). The results of the current study as well as the meta-analyses showed that there is no difference in the risk of adenomas, non-advanced adenomas, advanced adenomas, cancer, and polyps between the diverticulitis and screening groups. The quality of the best available evidence was moderate. It is therefore of the authors’ opinion, that patients should be considered for endoscopy on a case-by-case basis. Only patients who have uncertainty in the diagnosis, or those who have complicated diverticulitis should be offered endoscopic evaluation. The reported outcomes of the current study should be viewed and interpreted in the context of inherent limitations. In terms of the cohort study, our study had a retrospective design which subject our results to inevitable selection bias. The included patients in the diverticulitis group were older than the patients in the screening group; Moreover, the number of patients in the diverticulitis group was conspicuously smaller than the number of patients in the screening group. All of these, together with the fact that patients in the screening group underwent flexible sigmoidoscopy instead of colonoscopy, might have led to underestimation of the risk of adenomas and neoplastic lesions in the screening group. In terms of the meta-analysis, the best available evidence is derived from a limited number retrospective of studies which are subject to selection bias. The between study heterogeneity was high for almost all outcomes and the quality of the available evidence was moderate. All of these might have affected the robustness of our results.
The results of this study have shown no difference between diverticulitis and control groups in terms of its primary and secondary outcomes. It has therefore demonstrated that it may not be necessary to offer all patients with acute diverticulitis a subsequent colonoscopy. The implications of this in practice, would be a reduction in the number of unnecessary colonoscopies, and therefore a subsequent reduction in associated morbidity and cost.
The best available evidence currently is derived from a limited number of retrospective studies with moderate quality. High quality prospective studies are required for definite conclusions.