LAUSR

ABSTRACT Background and Aims: Eosinophilic esophagitis (EoE) is a chronic inflammatory disorder that requires repeat endoscopic evaluation(s) to assess response to treatment. This results in high health care costs and a procedural burden in affected children. Noninvasive alternate modalities to reassess disease activity have not been established. Low baseline impedance measured by multichannel pH impedance (pH-MII) is seen in adults with EoE, in keeping with poor mucosal integrity. We aimed to investigate the relationship between esophageal eosinophilia (or severity of eosinophilic infiltration) and baseline impedance in children with EoE. Methods: We retrospectively identified 15 children diagnosed with EoE at our institution who had undergone pH-MII within 30 days of 3-level esophageal biopsy. This group were not concurrently prescribed proton pump inhibitors and had negligible reflux parameters on pH-MII. Average impedance baseline was calculated upper, mid, and lower esophageal segments via baseline impedance automated analysis (RIAA) and mean nocturnal baseline impedance (MNBI) methods. Eosinophil count data for upper, mid, and lower esophageal segments in the EoE group was collated. Results: A significantly lower baseline impedance was seen across the esophageal length in children with EoE, compared with 30 controls who had no differences in age or reflux burden on nonparametric testing. A relationship between baseline impedance and eosinophil number at corresponding esophageal segments was not established. Conclusions: Baseline impedance may be an important, less invasive adjunct in clinical practice to monitor treatment response in children with EoE. Larger prospective cohort studies should delineate optimally predictive baseline impedance thresholds for active and inactive disease.