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P204 Re-established CRP cut-off in UC; it may be a better predictor of mucosal remission

O.K. Bakkaloglu, T. Eskazan, S. Bozcan, S. Yıldırım, E.A. Kurt, A.İ. Hatemi, Y. Erzin, F. Celik

Department of Gastroenterology, Istanbul University Cerrahpasa, Istanbul, Turkey

Background

Although faecal calprotectin can predict mucosal remission in ulcerative colitis, the CRP level in this context is insufficient and frequently stay under the current cut off level. While some patients with active mucosal disease have normal CRP levels most patients in mucosal remission have much lower CRP levels. The aim of this study is to define CRP cut off levels in the prediction of mucosal remission, considering both extensiveness and severity, in ulcerative colitis.

Methods

We retrospectively reviewed colonoscopy reports of ulcerative colitis patients (who are not on any steroid treatment at that time) which were performed between December 2016 and March 2019 and also their CRP levels which were obtained at the same week of the colonoscopy examination. We excluded the data of patients with any other possible cause of inflammation or infection at the time of laboratory assessment. Degree of mucosal disease at colonoscopy was evaluated according to endoscopic Mayo score. Mucosal remission was defined as endoscopic Mayo score 0 or 1. The extent of mucosal inflammation was classified according to Montreal classification. The CRP level with optimal sensitivity and specificity for mucosal remission prediction was assessed by ROC curve analysis and positive and negative predictive values were also calculated.

Results

A total of 331 colonoscopy reports of 260 patients (122 m, 138 f) were involved in this study. There were no significant differences between ages of patients when compared with ex, and Montreal classification and we did not find any correlation between age and CRP levels. Sensitivity, specificity, positive predictive value and negative predictive values for 5 mg/l, 3 mg /l and 2 mg/l are summarised in Table 1. CRP levels which predict Mayo 0 disease, mucosal remission (Mayo 0–1) and Mayo 3 disease are shown in Table 2. At the ROC curve analysis, we found that CRP level of approximately 2.9 mg/l can predict mucosal remission with a 77% sensitivity and % 80 specificity in all examinations without grouping into a separate segmental disease. For subgroups with Montreal E1, E2 and E3 ROC curve analysis suggested 1,8 mg/l (sn. 84%, sp. 90%), 2,7 mg/l (sn. 75%, sp. 75%) and 3 mg/l (sn. 80%, sp. 80%) CRP levels can be used for prediction of mucosal remission respectively (Table 3). It is important to emphasise that 30% of all patients with Mayo 3 colonoscopy and further 23% of patients with Montreal E3–Mayo 3 activity have CRP levels below the regular cut-off value of 5 mg/l.

Conclusion

CRP cut-off level of approximately 2.9 mg/l can predict mucosal remission in ulcerative colitis better than standard cut-off of 5 mg/l which has a low positive predictive value and specificity even at extended and active mucosal disease.