Summary: Background: The frequency of eosinophilic oesophagitis (EoE) occurrence is escalating. Current diagnostic criteria recently proposed for the disease, determine that previous estimates of incidence and prevalence are outdated.Aim: To gauge the current incidence and prevalence of EoE by performing a systematic review of population‐based studies.Methods: Three electronic databases were searched from their inception dates to September 2018. A total of 2386 documents were screened; 29 studies reported on the prevalence and incidence of EoE in the general population.Results: The pooled prevalence of EoE was 34.4 cases per 100 000 inhabitants (95% CI, 23.1‐47.5), and was higher for adults (42.2; 95% CI, 31.1‐55) than for children (34; 95% CI, 22.3‐49.2). The pooled EoE incidence rates were 6.6/100 000 person‐years (95% CI, 3‐11.7) in children and 7.7/100 000 (95% CI, 1.8‐17.8) in adults. No differences were found between North American and European studies using varied sources of data (insurance and administrative databases compared to hospital‐bases case series). Subgroup analysis according to risk of bias did not change results significantly. A steady rise in EoE incidence and prevalence rates was observed over time, comparing studies conducted under subsequent definitions for EoE. No significant publication bias was found.Conclusions: In a systematic review and meta‐analysis, we found a sharp increase, higher than previous estimates, in the incidence and prevalence of EoE in population based studies. Results from studies carried out in developed countries show broad consistency and provide evidence of increasing pooled prevalence and incidence of EoE rates over time.

Studies of inflammatory bowel disease (IBD) have been inconclusive in relating microbiota with distribution of inflammation. We report microbiota, host transcriptomics, epigenomics and genetics from matched inflamed and non-inflamed colonic mucosa [50 Crohn’s disease (CD); 80 ulcerative colitis (UC); 31 controls]. Changes in community-wide and within-patient microbiota are linked with inflammation, but we find no evidence for a distinct microbial diagnostic signature, probably due to heterogeneous host-microbe interactions, and show only marginal microbiota associations with habitual diet. Epithelial DNA methylation improves disease classification and is associated with both inflammation and microbiota composition. Microbiota sub-groups are driven by dominant Enterbacteriaceae and Bacteroides species, representative strains of which are pro-inflammatory in vitro, are also associated with immune-related epigenetic markers. In conclusion, inflamed and non-inflamed colonic segments in both CD and UC differ in microbiota composition and epigenetic profiles.

Summary: Background: Proton pump inhibitors (PPIs) are the most commonly used first‐line therapy for patients with eosinophilic oesophagitis (EoE). However, many aspects related to PPIs in EoE are still unknown.Aims: To assess the effectiveness of PPI therapy for EoE in real‐world practice.Methods: This cross‐sectional study collected data on PPI efficacy from the multicentre EoE CONNECT database. Clinical remission was defined as a decrease of ≥50% in dysphagia symptom score; histological remission was defined as a peak eosinophil count below 15 eosinophils per high‐power field. Factors associated with effectiveness of PPI therapy were identified by binary logistic regression multivariate analyses.Results: Overall, 630 patients (76 children) received PPI as initial therapy (n = 600) or after failure to respond to other therapies (n = 30). PPI therapy achieved eosinophil density below 15 eosinophils per high‐power field in 48.8% and a decreased symptom score in 71.0% of patients. More EoE patients with an inflammatory rather than stricturing phenotype accomplished clinico‐histological remission after PPI therapy (OR 3.7; 95% CI, 1.4‐9.5); as well as those who prolonged treatment length from 8 to 12 weeks (OR 2.7; 95% CI, 1.3‐5.3). After achieving clinico‐histological remission of EoE, PPI dosage reduction was effectively maintained in 69.9% of patients, but tended to be less effective among those with a stricturing phenotype.Conclusions: Inflammatory EoE phenotype and treatment duration up to 12 weeks correlated with greater chance for inducing remission of EoE. A stricturing phenotype decreased response rates to PPI therapy both initially and in the long term.

Alterations in short chain fatty acid metabolism, particularly butyrate, have been reported in inflammatory bowel disease, but results have been conflicting because of small study numbers and failure to distinguish disease type, activity or other variables such as diet. We performed a comparative assessment of the capacity of the microbiota for butyrate synthesis, by quantifying butyryl-CoA:acetate CoA-transferase [BCoAT] gene content in stool from patients with Crohn’s disease [CD; n = 71], ulcerative colitis [UC; n = 58] and controls [n = 75], and determined whether it was related to active vs inactive inflammation, microbial diversity, and composition and/or dietary habits. BCoAT gene content was quantified by quantitative polymerase chain reaction [qPCR]. Disease activity was assessed clinically and faecal calprotectin concentration measured. Microbial composition was determined by sequencing 16S rRNA gene. Dietary data were collected using an established food frequency questionnaire. Reduced butyrate-synthetic capacity was found in patients with active and inactive CD [p < 0.001 and p < 0.01, respectively], but only in active UC [p < 0.05]. In CD, low BCoAT gene content was associated with ileal location, stenotic behaviour, increased inflammation, lower microbial diversity, greater microbiota compositional change, and decreased butyrogenic taxa. Reduced BCoAT gene content in patients with CD was linked with a different regimen characterised by lower dietary fibre. Reduced butyrate-synthetic capacity of the microbiota is more evident in CD than UC and may relate to reduced fibre intake. The results suggest that simple replacement of butyrate per se may be therapeutically inadequate, whereas manipulation of microbial synthesis, perhaps by dietary means, may be more appropriate.