We aimed to identify early noninvasive predictors of clinical and endoscopic remission in children with Crohn disease (CD) under infliximab (IFX).
Prospective observational study conducted in children with moderate-to-severe CD starting IFX. All patients underwent weighted pediatric CD activity index (wPCDAI) assessment, C-reactive protein and fecal calprotectin (FC) at week 0, 14, and 48. Endoscopy was performed at 0 and 48 weeks. The primary outcome was to determine the ability of 14-week wPCDAI, C-reactive protein, and FC to predict 1-year steroid-free clinical remission and mucosal healing. As a secondary outcome we evaluated their concordance with Simple Endoscopic Score for CD (SES-CD) at week 48.
Forty-one children were enrolled. At 1 year, 21 (51%) and 16 (39%) were in clinical and endoscopic remission. Only combined postinduction FC and wPCDAI were able to predict 1-year clinical and endoscopic remission (hazard ratio 4.81 [95% confidence interval 1.76-20.45], P = 0.05 and hazard ratio 5.51 [95% confidence interval 1.83-26.9], P = 0.03). One-year SES-CD moderately correlated with FC (r = 0.52; P = 0.001). The FC cut-off value for mucosal healing was 120.5 μg/g (area under the curve 0.863, 83% sensitivity, 75.5% specificity; P = 0.005). The concordance between wPCDAI and SES-CD was excellent and good for severe disease and remission (k 0.87 and 0.76).
Post induction FC combined with wPCDAI can predict 1-year clinical and endoscopic response to IFX in pediatric CD. FC shows a moderate correlation with SES-CD, whereas wPCDAI has a good concordance with endoscopic remission or severe disease, but not with mild and moderate disease.