An EREFS threshold of 2 or less is robust for assessing endoscopic response to treatment of eosinophilic esophagitis

Objectives: Assessment of eosinophilic esophagitis (EoE) endoscopic findings is critical in determining disease activity. However, response thresholds for the EoE Endoscopy Reference Score (EREFS) are not definitively established. We assessed EREFS response thresholds in EoE patients treated with topical corticosteroids (tCS). Methods: We conducted a retrospective cohort study of newly diagnosed EoE patients treated with tCS who had a follow-up endoscopy with biopsy and EREFS assessed pre/post treatment. We explored endoscopic response thresholds. Patients with and without endoscopic response were compared and predictors of response were determined. Histologic and global symptom responses were determined and residual endoscopic findings calculated. Results: Of 333 patients, 219 (68%), 206 (62%), 142 (43%), 70 (21%), 139 (42%), and 142 (43%) met response thresholds for EREFS≤2, EREFS≤2 with no components >1 nor worsening of any component, EREFS≤1, EREFS=0, inflammatory subscore=0, and fibrostenotic subscore=0, respectively. On multivariate analysis, lower BMI (aOR: 0.90; 95% CI: 0.85–0.95), heartburn (aOR: 2.74; 95% CI: 1.37–5.48), and lower total baseline EREFS (aOR: 0.57; 95% CI: 0.29–0.71) independently predicted EREFS≤2. Following treatment, 74% with EREFS≤2 vs. 23% with EREFS>2 (p<0.001) had histologic response at <15 eos/hpf. Endoscopic responders more frequently endorsed a global symptom response (89% vs. 56%; p<0.001) and had minimal residual endoscopic findings. Outcomes stratified for adults and children were comparable to the entire cohort. Conclusions: Post-treatment EREFS≤2 was consistent with symptom and histologic response for the entire cohort. These data support EREFS≤2 as a robust threshold to define endoscopic response.