Symptomatic Response to Antibiotics in Patients With Small Intestinal Bacterial Overgrowth:A Systematic Review and Meta-analysis

Background/Aims@#We performed a systematic review and meta-analysis evaluating the symptomatic response rate to antibiotics in patients with small intestinal bacterial overgrowth (SIBO). Similarly, we performed a meta-analysis on the symptomatic response to antibiotics in irritable bowel syndrome (IBS) patients with and without SIBO. @*Methods@#MEDLINE, EMBASE, Web of Science, and Cochrane databases were searched from inception to March 2021. Randomized controlled trials and prospective studies reporting dichotomous outcomes were included. @*Results@#There were 6 studies included in the first meta-analysis comparing the efficacy of antibiotics to placebo or no antibiotic. This included 196 patients, of whom 101 received antibiotics and 95 received placebo or no antibiotics. Significantly more patients improved with antibiotics (relative risk [95% CI] = 2.46 [1.33-4.55], P = 0.004). There were 4 studies included in the analysis comparing symptomatic response rates in IBS patients with or without SIBO with 266 IBS patients, of whom 172 had SIBO and 94 did not. The pooled response rate for symptomatic response was 51.2% in the SIBO group vs 23.4% in the no SIBO group, respectively. Significantly more IBS patients with SIBO responded to antibiotics compared to those without SIBO (relative risk [95% CI] = 2.07 [1.40-3.08], P = 0.0003). @*Conclusions@#Antibiotics appear to be efficacious in treating SIBO, although small sample sizes and poor data quality limit this interpretation. Symptomatic response rates also appear to be higher in IBS patients with SIBO. This may be the first example of precision medicine in IBS as opposed to our current empiric treatment approach. Large-multicenter studies are needed to verify the results.

Lower and Upper Gastrointestinal Symptoms Differ Between Individuals With Irritable Bowel Syndrome With Constipation or Chronic Idiopathic Constipation

BACKGROUND/AIMS: We evaluated the distribution of lower and upper gastrointestinal (GI) symptoms among individuals with irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation (CIC) in a nationwide survey. METHODS: Individuals (≥ 18 years of age) were identified from a nationwide sample of > 70 000 United States adults. Participants completed the National Institutes of Health GI Patient Reported Outcomes Measurement Information System (NIH GI-PROMIS) questionnaire. Symptom frequency and intensity in the prior 7 days were assessed using validated PROMIS scores. Odds ratios (OR) with 95% confidence intervals (CI) were calculated to compare symptom prevalence in IBS-C vs CIC, and one-way ANOVA was used to assess differences in PROMIS scores. Regression analysis was performed to adjust for demographic variables. RESULTS: Nine hundred and seventy adults met eligibility criteria (275 with IBS-C, 734 with CIC). Demographics were similar among groups except for education, marital and employment status, and income. Adjusting for demographic differences, GI-PROMIS scores of global GI symptoms were higher in IBS-C (251.1; 95% CI, 230.0–273.1) compared to CIC (177.8; 95% CI 167.2–188.4) (P < 0.001). Abdominal pain was more prevalent (OR, 4.3; 95% CI, 2.9–6.6) and more severe (P = 0.007) in IBS-C. Constipation was more severe in IBS-C (P = 0.011). Incontinence was more common (OR, 2.9; 95% CI, 1.3–6.3) but just as severe (P = 0.389) in IBS-C versus CIC. Regarding upper GI symptoms, the prevalence of dysphagia, heartburn, and nausea were similar. However, IBS-C individuals had more severe heartburn (P = 0.001). CONCLUSION: GI symptoms are generally more severe in IBS-C compared to CIC, however abdominal pain, bloating, and upper GI symptoms still commonly occur in CIC.

Use of Dietary Management in Irritable Bowel Syndrome: Results of a Survey of Over 1500 United States Gastroenterologists

BACKGROUND/AIMS: Dietary therapy is increasingly used to manage gastrointestinal (GI) symptoms in patients with irritable bowel syndrome (IBS). We aim to gauge United States gastroenterologists’ perceptions of dietary therapies for IBS. METHODS: We distributed a 22-question survey to members of the American College of Gastroenterology. The survey was developed by gastroenterologists and survey methodologists. We collected information pertaining to demographics, providers’ interpretation of their patients’ views on dietary therapy, and gastroenterologists’ perceptions on dietary therapy, and nutritional counseling in IBS. RESULTS: One thousand five hundred and sixty-two (14%) surveys were collected. Nearly 60% of participants reported that patients commonly associate food with GI symptoms. IBS patients most commonly use a trial and error approach followed by a lactose-free and gluten-free diet, and rarely use a low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet on their own. Over half of providers recommend diet therapy to > 75% of IBS patients and most commonly recommend a low FODMAP diet. Only 21% of gastroenterologists commonly refer IBS patients to registered dietitians, and only 30% use GI dietitians. Female providers were more likely than males to recommend dietary changes as the primary mode of therapy (OR, 1.43 [1.09–1.88]; P = 0.009). CONCLUSIONS: Our national survey identified enthusiasm for diet treatment of IBS. While patients infrequently tried a low FODMAP diet on their own, GI providers commonly recommended this diet. Only a minority of GI providers refer their IBS patients to a registered dietitian for nutrition counseling and few refer patients to dietitians with specialized GI training. Female providers were more enthusiastic about diet therapies than males.

Artificial Sweeteners: A Systematic Review and Primer for Gastroenterologists

Artificial sweeteners (AS) are ubiquitous in food and beverage products, yet little is known about their effects on the gastrointestinal (GI) tract, and whether they play a role in the development of GI symptoms, especially in patients with irritable bowel syndrome. Utilizing the PubMed and Embase databases, we conducted a search for articles on individual AS and each of these terms: fermentation, absorption, and GI tract. Standard protocols for a systematic review were followed. At the end of our search, we found a total of 617 eligible papers, 26 of which were included. Overall, there is limited medical literature available on this topic. The 2 main areas on which there is data to suggest that AS affect the GI tract include motility and the gut microbiome, though human data is lacking, and most of the currently available data is derived from in vivo studies. The effect on motility is mainly indirect via increased incretin secretion, though the clinical relevance of this finding is unknown as the downstream effect on motility was not studied. The specific effects of AS on the microbiome have been conflicting and the available studies have been heterogeneous in terms of the population studied and both the AS and doses evaluated. Further research is needed to assess whether AS could be a potential cause of GI symptoms. This is especially pertinent in patients with irritable bowel syndrome, a population in whom dietary interventions are routinely utilized as a management strategy.

Emerging Pharmacologic Therapies for Constipation-predominant Irritable Bowel Syndrome and Chronic Constipation

Irritable bowel syndrome with constipation and chronic functional constipation are common digestive disorders that negatively impact quality of life and account for billions of dollars in health care costs. Related to the heterogeneity of pathogenesis that underlie these disorders and the failure of symptoms to reliably predict underlying pathophysiology, traditional therapies provide relief to only a subset of affected individuals. The evidence surrounding new and emerging pharmacologic treatments, which include both luminally and systemically acting drugs, is discussed here. These include agents such as lubiprostone, bile acid modulations, guanylate cyclase-C receptor agonists, serotonin receptor modulators and herbal therapies.

Pharmacologic and Complementary and Alternative Medicine Therapies for Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder characterized by episodic abdominal pain or discomfort in association with altered bowel habits (diarrhea and/or constipation). Other gastrointestinal symptoms, such as bloating and flatulence, are also common. A variety of factors are believed to play a role in the development of IBS symptoms, including altered bowel motility, visceral hypersensitivity, psychosocial stressors, altered brain-gut interactions, immune activation/low grade inflammation, alterations in the gut microbiome, and genetic factors. In the absence of biomarkers that can distinguish between IBS subgroups on the basis of pathophysiology, treatment of this condition is predicated upon a patient's most bothersome symptoms. In clinical trials, effective therapies have only offered a therapeutic gain over placebos of 7-15%. Evidence based therapies for the global symptoms of constipation predominant IBS (IBS-C) include lubiprostone and tegaserod; evidence based therapies for the global symptoms of diarrhea predominant IBS (IBS-D) include the probiotic Bifidobacter infantis, the nonabsorbable antibiotic rifaximin, and alosetron. Additionally, there is persuasive evidence to suggest that selected antispasmodics and antidepressants are of benefit for the treatment of abdominal pain in IBS patients. Finally, several emerging therapies with novel mechanisms of action are in development. Complementary and alternative medicine therapies including probiotics, herbal therapies and acupuncture are gaining popularity among IBS sufferers, although concerns regarding manufacturing standards and the paucity of high quality efficacy and safety data remain.