Performance and Interpretation of Hydrogen and Methane Breath Testing Impact of North American Consensus Guidelines.

BACKGROUND: Hydrogen and methane breath tests (HMBT) are widely used clinical investigations but lack standardization. To address this, the North American Consensus (NAC) group published evidence-based recommendations for HMBT. AIMS: To evaluate results obtained using NAC recommendations for HMBT, compared to retrospective data that utilized guidelines previously recommended. METHODS: HMBT data from 725 patients referred for small intestinal bacterial overgrowth (SIBO) and/or carbohydrate malabsorption (CM) testing were analyzed. Data were compared regarding dose of substrate for SIBO testing (16 vs. 10 g lactulose, and 50 vs. 75 g glucose) and the effect of post-ingestion sampling period for malabsorption testing. The effect of different recommended cut-off values for SIBO were examined. RESULTS: Substrate dose did not affect methane production. 10 g lactulose significantly reduced positive SIBO results compared to 16 g lactulose (42 vs. 53%, p = 0.04). 75 g glucose significantly increased positive results compared to 50 g glucose (36 vs. 22%, p = 0.04). Provoked symptoms were significantly more prevalent in patients testing positive by both North American Consensus and Ledochowski cut-off values. 34.5% of patients tested positive for CM at 180-min compared to 28% at 120-min (not significant, p = 0.19). CONCLUSIONS AND INFERENCES: 10 g lactulose substrate produces fewer positive SIBO results than 16 g lactulose, while 75 g glucose dose produces more positive SIBO results than 50 g. Performing CM breath tests for 180 min increases number of positive results when compared to 120 min. SIBO cut-off timings require further investigation, but our findings broadly support the NAC recommendations for SIBO and CM testing.

The prevalence of rumination syndrome and rumination disorder: A systematic review and meta-analysis.

BACKGROUND: Rumination is characterized by the repeated regurgitation of food. Rumination syndrome is a disorder of gut-brain interaction diagnosed by Rome criteria, whereas rumination disorder is a feeding and eating disorder diagnosed by DSM-5 criteria. We aimed to determine the global prevalence of rumination according to these criteria across all age groups. METHODS: We performed a systematic review and meta-analysis of studies reporting the prevalence of rumination syndrome according to Rome III and Rome IV and rumination disorder according to the following validated DSM-5 assessments: PARDI, EDA-5, EDY-Q, STEP, and STEP-CHILD. We searched MEDLINE, EMBASE, and PsychINFO (from January 1, 2006, to June 1, 2023) to identify studies reporting the prevalence of rumination in community settings in participants of any age. We did a meta-analysis to estimate the pooled prevalence and odds ratio (OR) of rumination according to diagnostic criteria, country, and characteristics such as age and sex. KEY RESULTS: The search strategy generated 1243 studies, of which 147 studies appeared to be relevant. Thirty studies were included, with a total of 114,228 participants, of whom 61,534 of these were adults and 52,694 were children. The pooled prevalence of rumination syndrome in children of all ages according to Rome III criteria was 1.0% (95% CI 0.3-1.6; I2 91.1%), but no data were available for adults. According to Rome IV criteria, the pooled prevalence of rumination syndrome in children of all ages was 0.4% (95% CI 0.2-0.6; I2 56.4%) and 3.7% in adults (95% CI 2.3-5.1; I2 91.4%). The pooled prevalence of rumination disorder in children of all ages according to EDY-Q was 2.1% (95% CI 0.9-3.4; I2 = 78.1%), but only one study utilizing EDY-Q in adults was included (0.7% [95% CI 0.4-1.0]). No data were available for children or adults using any other validated DSM-5 assessments for rumination disorder. Irrespective of diagnostic criteria, the pooled prevalence of rumination was higher in adults compared to children and adolescents (3.0% [95% CI 1.4-4.7; I2 = 98.1%] vs. 0.8% [95% CI 0.4-1.3; I2 = 90.8%]), but higher in adolescents than in children (1.1% [95% CI 0.3-2.0; I2 = 92.8%] vs. 0.1% [95% CI 0.0-0.2; I2 = 24.5%]). In adults, factors independently associated with rumination were female gender (OR 1.4 [95% CI 1.0-2.0]), anxiety (OR 2.3 [95% CI 2.1-2.6]), and depression (OR 1.8 [95% CI 1.2-2.9]). No association between gender and rumination was seen in children. CONCLUSIONS AND INFERENCES: The prevalence of rumination is more common in adults than in children. In adults, rumination is associated with female gender, anxiety, and depression. Future population studies should aim to better understand why this behavior is more common in adults and also compare validated DSM-5 assessments for rumination disorder with Rome criteria for rumination syndrome as prevalence may differ.

An insight into the functional alterations in the gut microbiome of healthy adults in response to a multi-strain probiotic intake: a single arm open label trial.

Background: Probiotic supplements, by definition, provide a benefit to the host, but few studies have investigated the effect of probiotic supplements in healthy adult populations. Purpose: The present, single arm, open label clinical trial, evaluated compositional and functional changes in the fecal microbiome of healthy adults after supplementation with a 14-strain probiotic. Methods: We analysed the effect of a 14-strain probiotic blend (Bacillus subtilis NCIMB 30223, Bifidobacterium bifidum NCIMB 30179, B. breve NCIMB 30180, B. infantis NCIMB 30181, B. longum NCIMB 30182, Lactobacillus helveticus NCIMB 30184, L. delbrueckii subsp. bulgaricus NCIMB 30186, Lacticaseibacillus paracasei NCIMB 30185, Lactiplantibacillus plantarum NCIMB 30187, Lacticaseibacillus rhamnosus NCIMB 30188, L. helveticus NCIMB 30224, Lactobacillus salivarius NCIMB 30225, Lactococcus lactis subsp. lactis NCIMB 30222, and Streptococcus thermophilus NCIMB 30189), on the faecal microbiota of healthy young adults (n=41) in a single arm study. The adults consumed 4 capsules daily of the 14 strain blend(8 billion colony forming units/day) for 8 weeks. Compositional and functional changes in faecal microbiota before and after supplementation were assessed using shotgun metagenomic sequencing. Fasting breath analysis, faecal biochemistry and bowel habits were also assessed. Results: In healthy adult participants, no significant changes to the overall alpha- or beta-diversity was observed after 8 weeks of multi-strain probiotic supplementation. However, in a simplified model that considered only time and individual differences, significant decreases (p < 0.05) in family Odoribacteraceae and Bacteroidaceae abundance and a significant increase (p < 0.05) in genus Megamonas abundance were observed. At a functional level, there were significant changes in functional gene abundance related to several functional pathways, including phenylalanine metabolism, O-antigen nucleotide sugar biosynthesis, bacterial chemotaxis, and flagellar assembly. No significant changes in stool form or frequency, fecal biochemistry, or methane and hydrogen breath tests were observed. Conclusion: In healthy young adults, overall alpha- and beta-diversity did not change in response to probiotic intake even though modest compositional changes at the family and genus level were observed. However, at functional level, results identified changes in gene abundance for several functional pathways.

A double-blind randomised placebo-controlled trial investigating the effects of lesogaberan on the objective cough frequency and capsaicin-evoked coughs in patients with refractory chronic cough.

Objective: Baclofen is a centrally acting γ-aminobutyric acid type B (GABAB) receptor agonist which reduces gastro-oesophageal reflux and suppresses the cough reflex; however, central nervous system side-effects limit its use. Lesogaberan is a novel peripherally acting GABAB agonist, but its effects on refractory chronic cough are unknown. Design: We performed a single-centre, placebo-controlled, double-blind randomised crossover study in patients with chronic cough, refractory to the treatment of underlying conditions. Patients were randomised to treatment with lesogaberan 120 mg modified release twice daily or matched placebo for 2 weeks and then crossed over to the alternative therapy after a 2-week washout. The primary end-point was 24-h cough frequency measured with an acoustic monitoring system. In addition, cough responses to capsaicin were measured, and gastro-oesophageal reflux assessed by 24-h pH/impedance at screening. Results: 22 patients were randomised to receive lesogaberan/placebo or placebo/lesogaberan (female (73%); mean±sd age 63.7±7.2 years; median (interquartile range) cough duration 10.5 (5.8-17.0) years; mean (95% CI) 45 (29-67) reflux events in 24 h; two patients had abnormal oesophageal acid exposure times). Although lesogaberan reduced cough counts by 26% over placebo, this did not reach statistical significance (p=0.12). However, lesogaberan did significantly improve cough responses to capsaicin (p=0.04) and the number of cough bouts (p=0.04) compared with placebo. Lesogaberan was well tolerated in this study. Conclusions: Lesogaberan improved cough hypersensitivity and the number of bouts of coughing, but not coughs per hour. This implies a possible role for peripheral GABAB receptors in refractory chronic cough.