The increasing incidence and prevalence of eosinophilic oesophagitis outpaces changes in endoscopic and biopsy practice: national population-based estimates from Denmark

BACKGROUND: National population-based medical registries in Denmark offer a unique opportunity to study eosinophilic oesophagitis (EoE) epidemiology.

AIM: To determine the incidence and prevalence of EoE in Denmark, and evaluate whether an increase in endoscopy with biopsy activity explains changes in these trends.

METHODS: The Danish National Pathology Registry, Danish National Patient Registry and Danish Registry of Medicinal Product Statistics were queried from 1997 to 2012. Using an EoE case-finding algorithm validated for Danish patients, EoE cases were identified during each year of the study period; we also identified all patients with oesophageal eosinophilia. Using the known population of Demark, the annual incidence and prevalence of EoE were determined. We also determined the number of oesophageal biopsies performed each year in Denmark, and compared the change in the incidence rate to the change in biopsy rate.

RESULTS: Between 1997 and 2012, 1708 patients had oesophageal eosinophilia, of whom 844 met the case definition of EoE. There were seven new cases of EoE in 1997 and 145 new cases in 2012, corresponding to a 19.5-fold increase in incidence (0.13/100 000 to 2.6/100 000). There were 769 total cases in 2012 (prevalence of 13.8/100 000). Over the same time frame, the oesophageal biopsy rate increased only 1.9 fold, from 91.1/100 000 to 175.3/100 000.

CONCLUSIONS: The incidence and prevalence of EoE markedly increased in Denmark over the past 15 years. This increase far outpaced the increase in oesophageal biopsy utilisation, indicating that changes in the frequency of EoE are not due to changes in biopsy rates alone.