Disease course of eosinophilic esophagitis under anti-inflammatory treatment.

Background Eosinophilic esophagitis (EoE) is a chronic type-2 inflammatory disease of the esophagus that progresses to a fibrotic phenotype when left untreated. Current treatment options aim at controlling clinical, endoscopic and histological disease activity. However, as of yet, it remains elusive if achieving disease control, particularly the long-term control of histological disease activity, can prevent the development of disease complications.Objective To assess the impact of ongoing histological disease activity on the development of disease complications in adult EoE patients.Methods We evaluated prospectively-included patients in the Swiss EoE cohort. Data on all patients with ongoing maintenance treatment, and at least two follow-up visits, but without concomitant gastroesophageal reflux or strictures at baseline, were analyzed. We compared patients with ongoing histological disease activity vs patients with disease control, with regards to development of disease complications over time (strictures, bolus impactions and need for treatment escalation). Histological disease activity was defined by a peak eosinophil count of >15 eosinophil during all follow-up visits.Results We included a total of 151 patients with a median follow-up of 56.0 months (70.9% males, median age 39.0 years). 93 patients were classified as having disease control during follow-up (61.6%), while 58 patients (38.4%) showed ongoing histological disease activity. Development of complications occurred in a total of 108 patients (71.5%), significantly more often in patients with ongoing histological activity compared to patients with disease control (89.7% vs 60.2%, p<0.001). This difference was mainly due to higher rates of stricture formation and need for treatment escalation. Multivariate Cox regression models revealed ongoing histologic disease activity as a significant predictor for the development of complications in the follow-up (HR 2.45, p<0.001), particularly for need for treatment escalation (2.63, p<0.001) and development of strictures (HR 3.16, p=0.025).Conclusion Ongoing histological disease activity predicts development of complicating disease course in EoE patients. Current treatment strategies should aim at controlling both clinical and histological disease activity to prevent disease complications.