BACKGROUND: Faecal calprotectin [FCal] levels are used as a surrogate marker for mucosal inflammation, but thresholds for defining endoscopic or histological disease activity in ulcerative colitis [UC] remain unclear. METHODS: Using validated indices, prospective measurements of FCal, symptoms [Simple Colitis Clinical Activity Index, SCCAI], endoscopic [Ulcerative Colitis Endoscopic Index of Severity, UCEIS] and histological activity [Nancy index] were made over 6 months in patients enrolled into the TrueColours UC web-based monitoring programme. Repeated measurements correlation was performed between FCal and SCCAI, UCEIS, and Nancy indices using definitions for remission and active disease [UCEIS: remission ≤1, active ≥4; Nancy: remission ≤1, active ≥2; combined criteria: remission UCEIS ≤1 and Nancy ≤1, active UCEIS ≥4 and Nancy ≥2]. Receiver operating characteristic curves investigated FCal thresholds after maximising sensitivity for active disease. RESULTS: In 39 patients followed prospectively for 6 months, correlation coefficients between FCal and SCCAI, UCEIS, and Nancy indices were 0.271 (95% confidence interval [CI] 0.114-0.415), 0.741 [95% CI 0.289-0.922], and 0.876 [95% CI 0.605-0.965], respectively. Median FCal thresholds for remission using endoscopic, histological, or combined criteria were 71 μg/g [range 8-624], 91 μg/g [range 8-858], and 67 μg/g [range 8-479], respectively. The FCal threshold above which active disease was confirmed was 187 μg/g for UCEIS (area under the curve [AUC] 0.915), 72 μg/g for Nancy [AUC 0.824], and 187 μg/g for combined endoscopic and histological criteria [AUC 0.936]. CONCLUSIONS: Correlation between FCal and symptoms in UC is weak. In contrast, the correlation between FCal and endoscopic or histological activity is strong. An FCal ≥72 μg/g indicates histological inflammation [Nancy ≥2] and ≥187 μg/g indicates endoscopically active disease [UCEIS ≥4], whether combined with histopathology or not.
J Crohns Colitis
424 - 430
Faecal calprotectin, remission, ulcerative colitis, Area Under Curve, Biomarkers, Biopsy, Colitis, Ulcerative, Colon, Colonoscopy, Feces, Humans, Intestinal Mucosa, Leukocyte L1 Antigen Complex, Prospective Studies, ROC Curve, Severity of Illness Index, Symptom Assessment