P471 What is the appropriate cut-off value of CRP to predict endoscopic remission in ulcerative colitis patients with clinical remission?

Abstract Background A noninvasive and reliable markers for predicting endoscopic remission (ER) in ulcerative colitis (UC) patients with clinical remission (CR) provide important information in predicting disease progression and in determining treatment. Faecal calprotectin test is known to be the most accurate to predict ER, but patients are reluctant to handle faecal materials. C-reactive protein (CRP) is one of the surrogate markers for assessing disease activity, but it is known to have low sensitivity and specificity of normal CRP value (0.3 mg/dl). The sensitivity of the CRP test has been improved, and even fine values within the normal range can be measured. The aim of this study was to determine appropriate CRP cut-off values for the prediction of ER in UC patients with CR even though within normal CRP range. Methods A total of 132 UC patients who underwent endoscopic evaluation in CR were retrospectively reviewed. Serum biomarkers including haemoglobin, leukocytes, platelets, erythrocyte sedimentation rate, and CRP were evaluated within 1 week period from endoscopic evaluation. The clinical and endoscopic activity was measured by simple clinical colitis activity index and endoscopic Mayo subscore. Results In UC patient with CR, CRP level was significantly lower in ER (median 0.05, 0.03–2.57) vs. non-ER (median 0.11 0.03-2.81). (p 0.005) The proportion of males in non-ER was slightly higher than in ER (24, 72.7% vs. 52, 52.5 %; p = 0.042), and only gender and CRP showed statistical differences in baseline clinical characteristics. CRP had predictive value of ER Area under the curve (AUC = 0.760) and the sensitivity was 71.4%, specificity was 71.7 % at cut-off value of 0.09mg/dl. In contrast, the sensitivity and specificity of normal CRP (0.3mg/dl) were low. (sensitivity 27.3%, specificity 90.9%). Conclusion Norma CRP cut-off values are not sufficient to reflect ER. It may be helpful to change the CRP cut-off value that predicts ER in CR to value other than 0.3 mg/dl.