Improving Adherence to Clinical Practice Guidelines for Managing Gastric Intestinal Metaplasia Among Gastroenterologists at a US Academic Institution.

BACKGROUND: Clinical guidelines reserve endoscopic surveillance after a gastric intestinal metaplasia (GIM) diagnosis for high-risk patients. However, it is unclear how closely guidelines are followed in clinical practice. We examined the effectiveness of a standardized protocol for the management of GIM among gastroenterologists at a US hospital. METHODS: This was a preintervention and postintervention study, which included developing a protocol and education of gastroenterologists on GIM management. For the preintervention study, 50 patients with GIM were randomly selected from a histopathology database at the Houston VA Hospital between January 2016 and December 2019. For the postintervention study, we assessed change in GIM management in a cohort of 50 patients with GIM between April 2020 and January 2021 and surveyed 10 gastroenterologists. The durability of the intervention was assessed in a cohort of 50 GIM patients diagnosed between April 2021 and July 2021. RESULTS: In the preintervention cohort, GIM location was specified (antrum and corpus separated) in 11 patients (22%), and Helicobacter pylori testing was recommended in 11 of 26 patients (42%) without previous testing. Gastric mapping biopsies were recommended in 14% and surveillance endoscopy in 2%. In the postintervention cohort, gastric biopsy location was specified in 45 patients (90%, P <0.001) and H. pylori testing was recommended in 26 of 27 patients without prior testing (96%, P <0.001). Because gastric biopsy location was known in 90% of patients ( P <0.001), gastric mapping was not necessary, and surveillance endoscopy was recommended in 42% ( P <0.001). One year after the intervention, all metrics remained elevated compared with the preintervention cohort. CONCLUSIONS: GIM management guidelines are not consistently followed. A protocol for GIM management and education of gastroenterologists increased adherence to H. pylori testing and GIM surveillance recommendations.

New Model to Predict Recurrence After Endoscopic Mucosal Resection of Non-pedunculated Colonic Polyps ≥ 20 mm.

BACKGROUND: Polyp recurrence is common after endoscopic mucosal resection (EMR) of non-pedunculated colonic polyps ≥ 20 mm. Two models haven been published for polyp recurrence prediction: Sydney EMR recurrence tool (SERT) and the size, morphology, colonic site, and access to target (SMSA) score. None of these models have been evaluated in a real-world United States (U.S.) cohort. We aimed to evaluate the external validity of these two models and develop a new model. METHODS: Retrospective cohort study of patients with non-pedunculated polyps ≥ 20 mm that underwent EMR between 1/1/2012 and 6/30/2020. Univariate and multivariate analysis were performed to identify predictors of polyp recurrence to build a new model. Receiver Operating Characteristic (ROC) curves for the new model, SERT and a modified version of SMSA were derived and compared. RESULTS: A total of 461 polyps from 461 unique patients were included for analysis. The average polyp size was 29.1 ± 12.4 mm. Recurrence rate at first or second surveillance colonoscopy was 29.0% at a 15.6 months median follow up (IQR 12.3-17.4). A model was created with 4 variables from index colonoscopy: size > 40 mm, tubulovillous adenoma histology, right colon location and piecemeal resection. ROC curves showed that the Area Under the ROC (AUC) for the new model was 0.618, for SERT 0.538 and for mSMSA 0.550. CONCLUSION: SERT score and mSMSA have poor external validity to predict polyp recurrence after EMR of non-pedunculated polyps > 20 mm. Our new model is simpler and performs better in this multiethnic, non-referral cohort from the U.S.

Evolution of endoscopic mucosal resection (EMR) technique and the reduced recurrence of large colonic polyps from 2012 to 2020.

BACKGROUND: Endoscopic mucosal resection (EMR) is an effective method for removing non-pedunculated polyps ≥ 20 mm. We aimed to examine changes in EMR techniques over a 9-year period and evaluate frequency of histologic-confirmed recurrence. METHODS: We identified patients who underwent EMR of non-pedunculated polyps ≥ 20 mm at a safety net and the Veteran's Affairs (VA) hospital in Houston, Texas between 2012 and 2020. Odds ratios (ORs) and 95% confidence intervals (CI) for associations with recurrence risk were estimated using multivariable logistic regression. RESULTS: 461 unique patients were included. The histologic-confirmed recurrence was 29.0% at 15.6 months median follow up (IQR 12.3 - 17.4). Polyps removed between 2018 and 2020 had a 0.43 decreased odds of recurrence vs. polyps removed between 2012 and 2014. The use of viscous lifting agents increased over time (from 0 to 54%), and the use of saline was associated with increased risk of recurrence (OR 2.28 [CI 1.33 - 3.31]). CONCLUSIONS: Histologic-confirmed recurrence after EMR for non-pedunculated polyps ≥ 20 mm decreased over the seven year-period. Saline was associated with a higher risk of recurrence and the use of more viscous agents increased over time.

Spatial Characteristics of Colonic Mucosa-Associated Gut Microbiota in Humans.

Limited data exist on the spatial distribution of the colonic bacteria in humans. We collected the colonic biopsies from five segments of 27 polyp-free adults and collected feces from 13 of them. We sequenced the V4 region of the bacterial 16S rRNA gene using the MiSeq platform. The sequencing data were assigned to the amplicon sequence variant (ASV) using SILVA. Biodiversity and the relative abundance of the ASV were compared across the colonic segments and between the rectal and fecal samples. Bacterial functional capacity was assessed using Tax4fun. Each individual had a unique bacterial community composition (Weighted Bray-Curtis P value = 0.001). There were no significant differences in richness, evenness, community composition, and the taxonomic structure across the colon segments in all the samples. Firmicutes (47%), Bacteroidetes (39%), and Proteobacteria (6%) were the major phyla in all segments, followed by Verrucomicrobia, Fusobacteria, Desulfobacterota, and Actinobacteria. There were 15 genera with relative abundance > 1%, including Bacteroides, Faecalibacterium, Escherichia/Shigella, Sutterella, Akkermansia, Parabacteroides, Prevotella, Lachnoclostridium, Alistipes, Fusobacterium, Erysipelatoclostridium, and four Lachnospiraceae family members. Intra-individually, the community compositional dissimilarity was the greatest between the cecum and the rectum. There were significant differences in biodiversity and the taxonomic structure between the rectal and fecal bacteria. The bacterial community composition and structure were homogeneous across the large intestine in adults. The inter-individual variability of the bacteria was greater than inter-segment variability. The rectal and fecal bacteria differed in the community composition and structure.

Dietary quality and the colonic mucosa-associated gut microbiome in humans.

BACKGROUND: Despite tremendous interest in modulating the microbiome to improve health, the association between diet and the colonic mucosa-associated gut microbiome in healthy individuals has not been examined. OBJECTIVE: To investigate the associations between Healthy Eating Index (HEI)-2005 and the colonic mucosa-associated microbiota. METHODS: In this cross-sectional observational study, we analyzed bacterial community composition and structure using 16S rRNA gene (V4 region) sequencing of 97 colonic mucosal biopsies obtained endoscopically from different colon segments of 34 polyp-free participants. Dietary consumption was ascertained using an FFQ. Differences in α- and ß-diversity and taxonomic relative abundances between the higher and lower score of total HEI and its components were compared, followed by multivariable analyses. RESULTS: The structure of the microbiota significantly differed by the scores for total HEI, total and whole fruits (HEI 1 and HEI 2), whole grains (HEI 6), milk products and soy beverages (HEI 7), and solid fat, alcohol, and added sugar (HEI 12). A lower score for total HEI and HEIs 2, 7, and 12 was associated with significantly lower richness. A lower score for total HEI was associated with significantly reduced relative abundance of Parabacteroides, Roseburia, and Subdoligranulum but higher Fusobacterium. A lower score for HEI 2 was associated with lower Roseburia but higher Bacteroides. A lower score for HEI 7 was associated with lower Faecalibacterium and Fusobacterium but higher Bacteroides. A lower score for HEI 12 was associated with lower Subdoligranulum but higher Escherichia and Fusobacterium (false discovery rate-adjusted P values <0.05). The findings were confirmed by multivariate analysis. Less abundant bacteria such as Alistipes, Odoribacter, Bilophila, and Tyzzerella were also associated with dietary quality. CONCLUSIONS: A lower score for total HEI-2005 was significantly associated with reduced relative abundance of potentially beneficial bacteria but increased potentially harmful bacteria in the colonic mucosa of endoscopically normal individuals.

Dietary Nutrients Involved in One-Carbon Metabolism and Colonic Mucosa-Associated Gut Microbiome in Individuals with an Endoscopically Normal Colon.

One carbon (1C) metabolism nutrients influence epigenetic regulation and they are supplied by diet and synthesized by gut microbiota. We examined the association between dietary consumption of methyl donors (methionine, betaine and choline) and B vitamins (folate, B2, B6, and B12) and the community composition and structure of the colonic mucosa-associated gut microbiota determined by 16S rRNA gene sequencing in 97 colonic biopsies of 35 men. We used the food frequency questionnaire to assess daily consumption of nutrients, and the UPARSE and SILVA databases for operational taxonomic unit classification. The difference in bacterial diversity and taxonomic relative abundance were compared between low versus high consumption of these nutrients. False discover rate (FDR) adjusted p value < 0.05 indicated statistical significance. The bacterial richness and composition differed significantly by the consumption of folate and B vitamins (p < 0.001). Compared with higher consumption, a lower consumption of these nutrients was associated with a lower abundance of Akkermansia (folate), Roseburia (vitamin B2), and Faecalibacterium (vitamins B2, B6, and B12) but a higher abundance of Erysipelatoclostridium (vitamin B2) (FDR p values < 0.05). The community composition and structure of the colonic bacteria differed significantly by dietary consumption of folate and B vitamins.

Diverticulosis, Symptoms and Colonic Inflammation: A Population-Based Colonoscopy Study.

INTRODUCTION: Low-grade chronic inflammation has been suggested to play a role in uncomplicated asymptomatic and symptomatic diverticular disease. However, population-based studies are lacking. We investigated whether community participants with diverticulosis, with or without symptoms, would have colonic inflammation on histology and serology. METHODS: In a nested case-control study of 254 participants from the population-based colonoscopy (PopCol) study, colonic histological inflammatory markers and serological C-reactive protein levels were analyzed in cases with diverticulosis and controls without diverticulosis. Statistical methods included logistic and linear regression models. RESULTS: Background variables including age (P = 0.92), sex (P = 1.00), body mass index (P = 0.71), smoking (P = 0.34), and recent antibiotic exposure (P = 0.68) were similar between cases and controls. Cases reported more abdominal pain (P = 0.04) and diarrhea symptoms (mushy and high-frequency stools) than controls (P = 0.01 and P = 0.03, respectively) but were otherwise similar. The median C-reactive protein levels were similar among cases and controls [1.05 mg/L (0.3, 2.7) vs 0.8 (0.4, 2.2), P = 0.53]. There was a trend of increased numbers of cecal lymphoid aggregates in cases vs controls (P = 0.07), but no other associations between diverticulosis and inflammatory markers on histology were found. Similarly, no serological or mucosal inflammation was associated with symptomatic cases of diarrhea or abdominal pain vs asymptomatic controls. CONCLUSIONS: In a general community sample, both asymptomatic and symptomatic diverticulosis are not associated with colonic mucosal inflammation. Other explanations for symptomatic colonic diverticulosis need to be identified.