Evaluation of prognostic factors associated with proton pump inhibitors (PPIs) treatment failure and the need for second-line therapy in patients with EoE.

Retrospective study of patients with EoE treated with PPIs, during the decade 9/2013-9/2023. Data were collected prospectively. Demographic, clinical, endoscopic [Endoscopic Reference Score - EREFS] and histological characteristics were analyzed at diagnosis, at 24 weeks and then annually. Non-response was defined as a decrease of <50% in the Dysphagia Symptom Questionnaire (DSQ) score and/or >15 eosinophils/hpf at histology at week 24, while loss of response was defined as a relapse of the same parameters at the week 52 after an initial response.

Thirty-five patients (26Males/9Females), with a median age of 37 years [IQR (31-56)] and a median follow-up of 45 months [IQR (19-116)], were included. All patients received initial treatment with PPIs. Six (17.1%) patients required second-line treatment, five (14.3%) due to lack of initial treatment response and one (2.8%) due to loss of response to PPIs within 20.5 months, [IQR (14.2-61). The number of eosinophils at histology at diagnosis [44.5 IQR (41.5 -66.3)] was higher than in PPIs responders [35, IQR (26-42)] (p=0.009). These patients were also younger (median age 31.0 vs 30.5) and had a higher DSQ at diagnosis (mean 4.33±0.76 vs 4.10±0.24) though without statistically significant differences. In the ROC curve (AUC=0.845, p=0.009), the eosinophil count ≥41 predicted the need for second-line therapy with a sensitivity of 83.3% and specificity of 71.4% (PPV= 37.4%, NPV= 95%).

1) An increased number of eosinophils histologically at diagnosis is strongly correlated with failure of first-line treatment with PPIs in patients with Eosinophilic Esophagitis. 2) It may help predict PPI failure and indicate the need for earlier aggressive treatment.