Relationship of clinical symptoms with biomarkers of inflammation in pediatric inflammatory bowel disease

In adult inflammatory bowel disease (IBD) patients, there is a strong discrepancy between symptoms and biomarkers of inflammation. Data on pediatric IBD patients are conflicting. Therefore, we aimed to investigate the relationship between clinical symptoms and biomarkers of inflammation in pediatric IBD. Patients aged < 18 years with previously diagnosed Crohn's disease (CD) or ulcerative colitis (UC) were included. Clinical disease activity was determined using the abbreviated Pediatric CD Activity Index (aPCDAI) or Pediatric UC Activity Index (PUCAI). Biochemical disease activity was assessed using fecal calprotectin (FC) and C-reactive protein (CRP). In total, 127 patients (62 male; median age 14.9 years) were included (82 CD, 45 UC). FC correlated weakly with total aPCDAI score (r (s) = 0.32; 95 % CI 0.12-0.51; p = 0.003) and total PUCAI score (r (s) = 0.36; 95 % CI 0.07-0.62; p = 0.015). Only aPCDAI components abdominal examination and perirectal disease and PUCAI component activity level had a significant correlation with levels of FC. CRP correlated weakly with total aPCDAI score (r (s) = 0.28; 95 % CI 0.05-0.46; p = 0.012) and aPCDAI components abdominal examination and activity level. No significant correlation was observed between CRP and total PUCAI score (r (s) = 0.01; 95 % CI -0.34-0.29; p = 0.961) or individual PUCAI components. Conclusion: There is a strong discrepancy between clinical symptoms and biomarkers of inflammation in children with IBD.