Objectives: Fecal calprotectin (FC) is a well-integrated parameter in the monitoring of adolescent patients with inflammatory bowel disease (IBD). However, measurement of FC is limited by day-to-day-variation and by the feces consistency. Furthermore, adolescents are often noncompliant to deliver fecal sampling leading to suboptimal monitoring. Consequently, we see the need of a substitute biomarker whenever measurement of FC fails and aimed to investigate serum calprotectin (SC) in adolescents with IBD.
Methods: In cross sectional data from 19 ulcerative colitis (UC) patients <18 years old, a Spearman correlation was used to analyze the correlation between SC, FC, C-reactive protein (CRP) and endoscopic and symptom scores. In longitudinal data collected from 20 UC and Crohn disease (CD) patients (10-17 years old), Mixed Effect Models (MEM) were used to analyze the association between SC, FC, CRP, and symptom scores.
Results: We found positive correlations between SC (19 samples) and the endoscopic score, symptom score, and CRP (r = 0.56, P = 0.01; r = 0.64, P = 0.003; r = 0.97, P < 0.0001). We found no significant correlation between SC and FC. In 27 samples from UC patients, the association of SC with FC and CRP were positive and significant (P = 0.004, estimate = 0.32; P = 0.0001, estimate = 0.002). The association between SC and symptom score was insignificant. In 49 samples from CD patients, the association between SC and CRP was significant (P = 0.02, estimate = 0.002) whereas associations between SC and FC and symptom score were insignificant.
Conclusions: In the current pilot study, we found a correlation between SC and the endoscopically assessed inflammation in UC. SC may have the potential to improve disease monitoring of adolescent patients.