Eosinophilic esophagitis and allergic susceptibility: A systematic review and meta-analysis.

Background: Eosinophilic esophagitis (EoE) is a type 2 helper T (Th2) cell immune-mediated gastrointestinal disease. Accumulating evidence has supported allergic etiology as an underlying mechanism for EoE, but the magnitude of the correlation between EoE and atopy remains ambiguous. Hence, we performed a meta-analysis to evaluate and compare the rate of co-existing common atopic diseases between EoE and non-EoE patients. Methods: We searched through electronic databases and reference lists of review articles for studies describing co-existing rates of atopic diseases in EoE and non-EoE patients. EoE was diagnosed based on clinical and pathological evaluations. Risk of bias was assessed using the modified Newcastle-Ottawa Scale. Random-effects models were used for analyses. Quantitative results were presented as odds ratio (OR) and 95% confidence interval (CI). Subgroup analyses and sensitivity analyses were performed to explore and to identify heterogeneity across studies. Publication bias was examined by Egger's test and visualized by funnel plots. Results: Altogether, 27 studies containing 1831 cases and 2982 controls were enrolled. 57.2% of EoE patients had co-existing atopic disease. Patients with EoE were more likely to comorbid with atopic diseases (OR = 3.56, 95% CI: 2.27 to 5.59, Conclusions: Our findings suggest that EoE patients are more likely to comorbid atopic diseases, favoring the allergic diathesis of EoE. Clinicians should be alert for EoE in allergic patients having upper gastrointestinal symptoms. However, the causality between EoE and atopic diseases was not revealed and remains to be explored.