The epidemiology of eosinophilic esophagitis in Sweden - a nationwide population-based study.

Introduction: Eosinophilic esophagitis (EoE) is a chronic inflammatory condition that affects the esophagus. Previous studies have indicated a substantial increase of EoE over the last decades. The aim of the current study was to describe the incidence and prevalence of EoE over time and by geographical regions in Sweden, utilizing nationwide population-based registries.

Material and methods: The number of hospital admissions (in-patient and out-patient) for patients were identified using ICD-10-SE code K20.9A from the National Patient Registry between 1st January 2011 and 31st December 2021. Crude incidence and prevalence numbers were presented per 100,000 person years and persons, respectively.

Results: In 2011, no hospital visits of EoE were recorded. A total of 3,243 incident patients (2,379 (73.4%) men and 864 (26.6%) women) had a record of EoE between 2012 and 2021. The incidence increased over calendar year in where the incidence was from 1.59 per 100,000 person years in 2012 to 5.34 per 100,000 person years in 2021. The prevalence was 1.29 per 100,000 person years and 31.02 per 100,000 person years in 2012 and 2021, respectively. Major differences in the prevalence between geographical regions in Sweden were observed, e.g. in 2021, the prevalence was 12.24 in Västernorrland compared to 43.26 in Västra Götaland per 100,000 person years, which is similar to the prevalence in the Stockholm region.

Conclusion: The incidence and prevalence of eosinophilic esophagitis has significantly increased over calendar year but differs between geographical regions in Sweden. These differences should be further investigated.