EoE is recognized today as a common disease, the frequency of it is on the increase. In recent years, several studies have attempted to define the extent of EoE by estimating its frequency in different populations. Varied methodological approaches have been employed, from population-based research to studies defining the frequency of EoE in series of endoscopies and esophageal biopsies. However, differences in the methods used made of some comparisons especificaly tricky, and neither the epidemiology
of EoE nor its temporal trends as observed in population-based studies has been systematically evaluated to date, thus hampering a reliable and accurate estimation of the magnitude of the problem.
In a recent systematic review (which consists on a structured literature review focused on a research question that tries to identify, appraise, select and synthesize all high quality research evidence relevant to that question), a group of Spanish researchers has evaluated how common is EoE in terms of incidence (or the number of new cases that appear every year) and prevalence (or the accumulated number of patients that already exist).
In the paper that has been published in a recent number of the medical journal Alimentary Pharmacology and Therapeutics, the authors retrieved 13 original population-based studies from North America, Europe and Australia. The results showed high heterogeneity, but important figures to accurately assess the magnitude of the disease.
The pooled EoE incidence rate (the average number of new cases diagnosed every year was between 1.7 to 6.5 per 100 000 inhabitants (mean 3.7). The incidence was higher for adults that for children (7 versus 5.1 new cases /100,000 persons-year, respectively).
With regards to the prevalence (or the accumulate cases in the population in a given moment), an average of 28.1 EoE patients/100,000 inhabitants was found. Again, the disease was more common in adults than in children (43.4 versus 29.5 /100,000, respectively), and in American compared to European studies. No population-based studies were available from Asia, Africa and South America, in order to be included in this systematic review.
One of the most relevant findings of this study was that a steady rise in EoE incidence and prevalence rates was observed upon comparison of studies conducted before and after 2008.
This kind of high-quality studies are esential to inform health policies on the magnitude of EoE, that can be now recognized as a common cause of chronic symptoms in Developed countries.