P152 Faecal calprotectin 100 ug/g and 50 ug/g predict endoscopic and histologic remission: a prospective study in quiescent ulcerative colitis
H. Y. Shi*, F. K. Chan, A. Higashimori, A. Chan, J. Y. Ching, J. C. Wu, J. J. Sung, S. C. Ng
The Chinese University of Hong Kong, Hong Kong, China
Faecal calprotectin (FC) level correlates with mucosal inflammation. However, cut-off values of FC in identifying endoscopic and histologic remission in patients with quiescent ulcerative colitis (UC) remain unclear.
In this prospective study, consecutive adult patients with quiescent UC (defined as a Mayo stool frequency sub-score of 0 or 1, and a Mayo rectal bleeding subs-core of 0) underwent colonoscopy and had biopsies collected from each colonic segment. Endoscopic remission was defined as Mayo endoscopic sub-score ≤ 1. Histologic remission was defined as Geboes score < 2.0. The highest score amongst different segments of each patient was used for analysis. FC was determined by enzyme-linked immunosorbent assay. Circulating markers (white blood cell count, haemoglobin, platelet count, C-reactive protein [CRP], and erythrocyte sedimentation rate) were measured and correlated with endoscopic and histologic scores.
Enrolled were75 UC patients (54.7% male; median age 50 years). Endoscopic remission and histologic remission were seen in 63 (84.0%) and 35 (57.4%) patients, respectively. FC identified endoscopic remission with an area under the receiver operator characteristic curve (AUC) value of 0.824 (p = 0.006). The sensitivity and specificity of FC < 100ug/g to detect endoscopic remission were 77.8% and 85.7%, respectively. Endoscopic remission was achieved in 97.7% of patients with a FC level < 100ug/g (vs 66.7% of patients with FC level ≥ 100ug/g, p = 0.002). FC identified histologic remission with an AUC value of 0.742 (p = 0.003). The sensitivity, specificity, positive predictive value and negative predictive value of FC level < 50ug/g to identify histologic remission were 89.6%, 69.6%, 78.8%, and 84.2%, respectively. Histologic remission was achieved in 78.8% of patients with FC level < 50ug/g (vs 15.8% of those with FC level ≥ 50ug/g, p < 0.001). CRP correlated significantly with endoscopic remission (AUC = 0.697, p = 0.039), but not with histologic remission. Other circulating markers were not significant correlated with neither endoscopic nor histologic remission.
Level of FC at < 100 ug/g and < 50 ug/g reliably identified UC patients who had endoscopic and histologic remission, respectively. If colonoscopy is performed only in patients with FC level ≥ 50 ug/g, colonoscopy could be avoided in up to 90% of quiescent UC patients with histologic remission.