Surrogate markers of intestinal inflammation are predictive of relapse in patients with inflammatory bowel disease

Background&Aims: Prediction of relapse of inflammatory bowel disease has important implications for therapeutic stategies, We assessed whether measurement of intestinal permeability and inflammation could predict relapse of inflammatory bowel disease (IBD), Methods: Forty-three patients with Crohn's disease (CD) and 37 with ulcerative colitis (UC) in clinical remission provided a stool sample to be assayed for calprotectin (a neutrophil-specific marker), and patients with CD additionally underwent a small intestinal permeability test. Relapse was defined using clinical disease activity indices. Results: Twenty-five (58%) patients with CD and 19 (51%) with UC had a relapse over the 12-month period. Median calprotectin levels in the relapse groups (122 mg/L for CD, 123 mg/L for UC; normal <10 mg/L) differed significantly (P < 0.0001) from those of the nonrelapse groups (41.5 mg/L for CD, 29.0 mg/L for UC), At 50 mg/L, the sensitivity and specificity of calprotectin for predicting relapse in all patients with IBD were 90% and 83%, respectively. Permeability in the CD patients who relapsed (median, 0.075; normal <0.04) differed significantly (P = 0.004) from that in the nonrelapse group (median, 0,038), At the level of 0,05, the sensitivity and specificity of permeability in predicting relapse were 84% and 61%, respectively, Conclusions: Fecal calprotectin predicts clinical relapse of disease activity in patients with CD and UC, whereas small intestinal permeability is a useful predictor of relapse in patients with small intestinal CD.