Effectiveness of sigmoidoscopy for assessing ulcerative colitis disease activity and therapeutic response

Ulcerative colitis (UC) typically begins in the rectum and progresses proximally in a contiguous fashion without skip lesions. Post-treatment inflammation distribution can change over time. Colonoscopy is unpleasant for the patient and clinical trials often use sigmoidoscopy for evaluation of disease severity. The aim of this study is to evaluate whether sigmoidoscopy is adequate to assess disease activity and therapeutic response as colonoscopy. We retrospectively reviewed patients who underwent colonoscopy for the initial diagnosis and follow-up by evaluating their mucosal inflammation in our hospital from January 2012 and December 2017. A total of 69 patients were analyzed. During follow up, the inflamed segment changed post-treatment in 62% (43/69). Extensive UC was common in the changed disease extent group (P < .01). Patients treated with oral mesalazine had a higher rate of changed disease extent (P < .01). The sigmoid segment was the most commonly involved segment, and the rectum was the severely inflamed segment during initial diagnosis and follow-up. According to Mayo endoscopic subscore (MES) in the most severely inflamed colonic and rectosigmoid segment, there were high degrees of correlation in the initial UC diagnosis (r = .90, P < .01) and follow-up (r = .74, P < .01). Our findings suggest that sigmoidoscopy is effective as colonoscopy for detecting disease activity and evaluating therapeutic response in UC patients during follow-up.