Neutrophil-to-lymphocyte ratio at diagnosis predicts colonoscopic activity in pediatric inflammatory bowel diseases (pIBD).

Background: Neutrophil-to-lymphocyte ratio (NLR) is a novel biomarker studied in several autoimmune diseases including inflammatory bowel diseases (IBD) in adults, but poorly characterized in pediatric IBD (pIBD). We aimed to primarily investigate the relationship between NLR and pIBD endoscopic disease severity. We also examined whether NLR predicted hospitalization, surgery, and therapy response by 52 weeks.

Methods: We used the Canadian children IBD Network (CIDsCaNN) prospective inception cohort including patients<18 years old with baseline data from 2013-2022. We excluded patients with concurrent diseases affecting NLR. Both Mayo endoscopic score (MES) and simple endoscopic scale for Crohn Diseases (SES-CD) were dichotomized as low (quiescent-mild), and high activity (moderate-severe). For therapy responses, we examined year-1 steroid- and biologic-free remission. We used logistic regression for binary outcomes.

Results: 580 UC and 1081 CD patients were included. High NLR was associated with high activity MES and SES-CD in both univariate and multivariable analyses (OR=1.45, 95%CI= 1.07-1.97, p-value=0.016; and OR=1.42, 95%CI= 1.04-1.94, p-value=0.026, respectively). We also calculated the best NLR cutoff point to predict MES (1.90, sensitivity=68%, specificity=67%, AUC=0.67, AUC 95%CI= 0.59-0.74) and SES-CD (2.50, sensitivity=63%, specificity=69%, AUC=0.66, AUC 95%CI= 0.59-0.75) high activity. NLR did not predict therapy response in either UC or CD.

Conclusion: pIBD patients with high baseline NLR are more probable to have worse endoscopic disease at diagnosis. This highlights NLR potential as a reliable non-invasive biomarker of disease activity. The predictive power of NLR is based mostly on neutrophils and the balance between neutrophils and lymphocytes.