Are Colonoscopy and Bowel Ultrasound Useful for Assessing Response to Short-term Therapy and Predicting Disease Outcome of Moderate-to-severe Forms of Ulcerative Colitis?: a Prospective Study

Objectives: Mucosal healing has been proposed as an important sign of the efficacy of medical treatment of inflammatory bowel disease; however, direct evidence in ulcerative colitis (UC) is scarce. We evaluated the usefulness of colonoscopy and bowel ultrasound (US) as indexes of response to short-term therapy and as predictors of subsequent outcome in UC.

Methods: A total of 83 patients with moderate-to-severe UC were recruited; endoscopic and US severity was graded 0-3 at entry according to validated scores. Of the recruited patients, 74, who were clinically responsive to steroids, were followed up with repeated colonoscopy and bowel US at 3, 9, and 15 months from recruitment. Concordance between clinical, endoscopic, and US scores at various visits was determined by kappa statistics. Multiple unconditional logistic regression models were used to assess the predictivity of clinical, endoscopic, and US scores measured at 3 and 9 months on the development of endoscopic UC relapse within 15 months.

Results: A variable concordance was found over time between endoscopic and clinical score (weighted kappa between 0.38 and 0.95), with high and consistent concordance between endoscopic and US scores (weighted kappa between 0.76 and 0.90). On logistic regression analysis, moderate-to-severe endoscopic and US scores at 3 months were associated with a high risk of endoscopic activity at 15 months (odds ratio (OR): 5.2; 95% confidence interval (CI): 1.6-17.6 and OR: 9.1; 95% CI: 2.5-33.5, respectively).

Conclusions: Bowel US may be used as a surrogate of colonoscopy in assessing the short-term response of severe forms of UC to therapy. Both US score and endoscopic score after 3 months of steroid therapy predict outcome of disease at 15 months.