S843 Using Health Insurance Claims Data to Determine the Severity of Eosinophilic Esophagitis in Patients in the USA: A Retrospective Cohort Study

Introduction: Eosinophilic esophagitis (EoE) is a chronic, immune-mediated disease. If untreated/inadequately treated, the disease can progress from an inflammatory to a more severe, fibrostenotic phenotype. There is increasing interest in understanding the effect of disease severity on the burden of EoE. Methods: An algorithm was developed, based on the Index of Severity for EoE (I-SEE), to classify EoE disease severity using EoE-related diagnoses, procedures and complications identifiable in U.S. health insurance claims data. This analysis obtained data from a retrospective, observational cohort study using the Merative MarketScan Commercial, Medicare Supplemental and Medicaid databases over 3 years (July 1, 2020-June 30, 2023). Patients were included if they had ≥1 inpatient/outpatient claim with a diagnosis code for EoE (ICD-10-CM: K20.0; the date of the first claim during the selection window [July 1, 2021-June 30, 2022] was the index date) and 12 months of continuous health plan enrollment before and after the index date (baseline and follow-up periods, respectively). Patients were excluded if they had a diagnosis of eosinophilic gastritis/eosinophilic gastroenteritis (ICD-10-CM: K52.81) during the study. Using the algorithm developed, patients were classified as having mild, moderate or severe EoE based on the EoE-related diagnoses, procedures, and complications identifiable in the baseline period and 30 days after the index date. Patient demographics and clinical characteristics were reported, stratified by EoE severity. Results: Overall, 19,169 patients with EoE were identified. The mean (standard deviation) age of patients was 35.8 (18.5) years. The majority of patients were men (60.3%) and most had commercial insurance (73.8%). EoE disease severity was classified as mild, moderate, and severe in 67.5%, 24.9%, and 7.6% of patients, respectively. Compared with patients with mild or moderate EoE, those with severe disease were younger and a higher proportion were men. Patients with severe EoE also had lower levels of commercial insurance coverage, and the majority had an insurance claim for EoE during the baseline period (i.e., established EoE). Conclusion: This algorithm provides a useful tool for determining EoE disease severity outside of clinical practice using health insurance claims. The proportions of patients with mild, moderate, and severe EoE were similar to those reported in clinical studies using the I-SEE, supporting the validity of this method.