Faecal Calprotectin Predicts Endoscopic and Histological Activity in Clinically Quiescent Ulcerative Colitis.
INTRODUCTION
Faecal calprotectin [FC] is a reliable surrogate marker for disease activity in ulcerative colitis [UC]; however, there are no consensus cut-off values for remission. The study aim was to correlate FC with Mayo Endoscopic Score [MES] and histological disease activity of UC patients in clinical remission.


METHODS
Our study recruited adult UC patients at the McGill IBD Center between 2013 and 2017. Patients in clinical remission [partial Mayo score ≤2], undergoing endoscopy for disease activity or dysplasia surveillance, were enrolled. Before bowel preparation, FC was collected. MES was documented during colonoscopy. Biopsies were taken; histological activity was assessed using Geboes score and the presence of basal plasmacytosis.


RESULTS
A total of 185 patients were recruited. The area under the curve [AUC] in receiver operating characteristic [ROC] analysis to predict MES 1-3 [from 0] was 0.743 [95% CI 0.67-0.82; p <0.001] with an FC cut-off value 170 µg/g [64% sensitivity, 74% specificity], and to predict MES 2-3 [from 0-1] was 0.722 [95% CI 0.61-0.83; p <0.001] with an FC cut-off value 170 µg/g [69% sensitivity, 65% specificity]. To differentiate MES 0 from MES 1, an FC value 130 µg/g yields a 70% sensitivity and 68% specificity. The AUC in ROC analysis to predict Geboes <3.1 was 0.627 [95% CI 0.55-0.71; p = 0.003], with an FC value 135 µg/g [54% sensitivity, 69% specificity].


CONCLUSIONS
In this large study, FC ≥170 µg/g predicts endoscopic activity and FC ≥135 µg/g predicts histological activity. Therefore in clinical practice, lower faecal calprotectin thresholds can be chosen to optimise identification of patients with ongoing endoscopic and histological disease activity.
['Hart|Lara|L|', 'Chavannes|Mallory|M|', 'Kherad|Omar|O|', 'Maedler|Chelsea|C|', 'Mourad|Nathalie|N|', 'Marcus|Victoria|V|', 'Afif|Waqqas|W|', 'Bitton|Alain|A|', 'Lakatos|Peter L|PL|', 'Brassard|Paul|P|', 'Bessissow|Talat|T|']
D000328:Adult D015415:Biomarkers D003093:Colitis, Ulcerative D003113:Colonoscopy D003430:Cross-Sectional Studies D005243:Feces D005260:Female D006801:Humans D039841:Leukocyte L1 Antigen Complex D008297:Male D008875:Middle Aged D011237:Predictive Value of Tests D012372:ROC Curve D012720:Severity of Illness Index
Faecal calprotectin ulcerative colitis endoscopic healing histological remission