P561 Ulcerative Colitis Endoscopic Index of Severity (UCEIS) and Mayo Endoscopic Score (MES) in predicting the therapeutic effect of mesalazine in UC patients

Abstract Background The Ulcerative Colitis Endoscopic Index of Severity (UCEIS) and the Mayo Endoscopic Score (MES) were developed as an objective method of the endoscopic severity in ulcerative colitis (UC); however, it was still unclear whether UCEIS and MES could guide the mesalazine treatment in UC. Methods Consecutive UC patients who had undergone colonoscopy within 1 month before starting mesalazine between October 2011 and July 2016 were retrospectively evaluated. Demographic data, previous therapy, clinical observations, laboratory parameters, medical therapy and endoscopic assessments were documented. The primary outcome was the need for ‘step up’ treatment (containing the use of corticosteroids, immunomodulatory or surgery.) during admission and follow-up. Results Sixty-five patients were enrolled, 12(18.5%) needed ‘step up’ treatment’ due to primary or secondary nonresponse to mesalazine. UCEIS score is a predictor of primary or secondary nonresponse to mesalazine in multivariate analysis (OR, 25.65; 95% CI, 3.048–45.985; P =0.003). Receiver-operator characteristic (ROC) area of UCEIS is 0.95, with a sensitivity of 100% and specificity of 84.6%, using cut-off value of 6, which outperforms MES with the ROC area of 0.70; When UCEIS score ≥6, 60% of patients eventually need ‘step up’ treatment. Conclusion UCEIS score is a useful instrument for evaluating endoscopic improvement in UC patients treated with mesalazine. The high probability of mesalazine treatment failure and benefits of other therapy should be discussed in patients with baseline UCEIS ≥ 6.