Comments on “Adequacy of sigmoidoscopy as compared to colonoscopy for assessment of disease activity in patients of ulcerative colitis: a prospective study”

Article information

Intest Res. 2024;.ir.2024.00072

Publication date (electronic) : 2024 September 6

doi : https://doi.org/10.5217/ir.2024.00072

Sidharth Harindranath

Department of Gastroenterology, King Edward Memorial Hospital, Seth Gordhandas Sunderdas Medical College, Mumbai, India

Correspondence to Sidharth Harindranath, Department of Gastroenterology, King Edward Memorial Hospital, Seth Gordhandas Sunderdas Medical College, Multi-Storey Building, 9th floor, Mumbai 400012, India. Tel: +91-9137194804, Fax: +91-22-4103057, E-mail: h.sidharth@gmail.com

Received 2024 May 21; Accepted 2024 July 17.

I read with great interest the recent article by Patel et al. [1] reporting on the comparability of sigmoidoscopy with colonoscopy for endoscopic follow-up of patients with ulcerative colitis (UC). The authors demonstrated that in patients with UC with disease extent beyond the sigmoid colon, sigmoidoscopy showed strong agreement and excellent accuracy with colonoscopy for endoscopy and histological disease activity with extremely low chances of misclassification when sigmoidoscopy was performed in conjunction with histological activity assessment. The conclusion is that sigmoidoscopy is adequate for endoscopic follow-up in these patients [1]. The authors should be congratulated on this timely study which tries to answer a pertinent clinical question. However, some points are worth highlighting.

The previous studies that looked into this question were mostly retrospective with small sample sizes and heterogenous study population. Although this study claims to be a prospective cohort study, there is no follow-up period evident. Index colonoscopy was done for all patients included, and findings from the rectum and sigmoid (both endoscopic and histological) were compared with those of full colonoscopy. The conclusions drawn by the study vis-a-vis sigmoidoscopy are adequate on follow-up cannot be extrapolated from the results of the present study.

The study lacks stratification depending on disease extent unlike a similar study by Park et al. [2] Disease extent has definite therapeutic implications. Extensive disease is associated with greater severity compared to left-sided colitis with increased risk of colectomy and dysplasia [3]. A recent study by Vuyyuru et al. [4] has demonstrated the differential efficacy of advanced therapies in patients with moderate-to-severe UC. Tofacitinib and infliximab are more efficacious in patients with extensive colitis compared to left-sided colitis. It is well known that embryological, functional, and immunological differences exist between left- and right-sided colon in healthy humans. Currently, there is evidence to infer that extensive disease and left-sided disease are genetically distinct and have different immune pathways contributing to the pathophysiology. This has therapeutic implications as well as demonstrated by this study [4].

Most of the patients included in the study were predominantly mild disease as evidenced by the low clinical Mayo score and endoscopic subscores (Mayo Endoscopic Score of 2, Ulcerative Colitis Endoscopic Index of Severity of 3). Whether the conclusion of this study can be extrapolated to patients with moderate-to-severe disease is not clear at present. A study by Lin et al. [5] demonstrated that 7.6% of patients in their cohort required complete colonoscopy as they had extensive colitis. Moreover, patients with more severe disease activity more often required a complete colonoscopy assessment on follow-up (Mayo score: 3.48 vs. 4.66, P=0.02). Additionally, fecal calprotectin was higher in this group of patients and hence to confirm endoscopic and histological healing in this subset of patients according to the STRIDE consensus would warrant a complete colonoscopy [6].

In conclusion, while the study of Patel et al. [1] offers valuable insights, limitations including lack of follow-up data, disease extent stratification, and potential selection bias for mild disease raise questions about generalizability to real-world UC management, particularly in patients with moderate-to-severe disease. Further studies that address these limitations are necessary before definitively endorsing sigmoidoscopy as the sole follow-up modality for all UC patients.