Clinical Utility of Breath Tests in GI

Study Overview
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Brief Summary
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Bloating, gas, pain and diarrhea are common complaints. Routine investigations are negative; these patients are labeled as IBS. In these patients, whether testing for carbohydrate malabsorption or small intestinal bacterial overgrowth (SIBO) is useful is unclear. Investigators aim to assess the prevalence of SIBO, fructose and lactose intolerance, the usefulness of breath tests, and predictive value of pre-test symptoms.

Detailed Description
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Abdominal bloating, gas, belching, distension, and diarrhea are common gastrointestinal symptoms that are reported by at least 1/3rd of patients presenting to gastroenterology clinics. When routine endoscopic and radiological tests are negative1, most of these patients are labeled as irritable bowel syndrome (IBS) in gastroenterology practice2. Unfortunately these symptoms persist and these patients remain dissatisfied with their health care and continue to doctor shops or seek remedies from alternative care. Several studies have shown that these symptoms have a significant and negative impact on their quality of life. One possible explanation for their symptom is carbohydrate food intolerance. The Western diet has changed significantly over the last 3 decades. Today, large amounts of fructose are being consumed. This sugar is used as a sweetener in sodas, fruit juices, multiples beverages and candies. Although is naturally present in apples, peaches, pears and oranges, the exponential products and consumption of the synthetic high fructose corn syrup has alarmingly increased fructose consumption. When small amounts are ingested, fructose is completely absorbed from the gut mainly through Glut 5transporter from the intestinal brush border or through facilitated transport along glucose through the Glut 2 transporter5. If a person has either limited absorptive capacity or overwhelms normal absorption capacity by excess ingestion, then malabsorption of fructose ensues. This unabsorbed fructose can serve, as an osmotic load, that draws fluid into the intestinal lumen, causing abdominal bloating, gas, pain and diarrhea 6-7. Likewise lactose is a disaccharide that is present in dairy products and is widely consumed. After ingestion lactose is hydrolyzed in the small intestine by the brush border enzyme lactase into glucose and galactose that are in torn absorbed8. If lactose is malabsorbed by Glut 2, then it will serve as an osmotic load, and get rapidly propelled in to the colon where it is fermented by the colonic bacterial flora, into short chain fatty acid, hydrogen,methane and other gases, this lactose malabsorption produces gas, bloating, flatulence and diarrhea9. About 75% of the world´s population gradually lose their ability to produce the lactase enzyme after age 30 years10-11. Malabsorption or intolerance of carbohydrates such as fructose and lactose are common and frequently encountered both in the primary care and specialist gastroenterology clinics, but are poorly recognized or treated. Over the last decade, breath testing has emerged as a simple, non invasive method of identifying malabsorption and/ or intolerance to common food ingredients such as fructose12, and lactose13, as well as to identify small intestinal bacterial overgrowth (SIBO)14. However, they are only performed in selected academic centers, and their clinical utility and diagnostic yield largely remains unknown. Also may the clinical utility of performing a single breath test versus a cumulative battery of breath tests, such as glucose, lactose or fructose breath test, in a patient with unexplained GI symptoms is also not known. The aims of this study are to investigate a consecutive series of patients with unexplained chronic GI symptoms and examine; 1) the prevalence of SIBO answered by the glucose breath test, fructose and lactose intolerance answered by the fructose y lactose breath test, ; 2) the predictive value of pre-test symptoms in the diagnosis of SIBO or carbohydrate intolerance.

Official Title
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Clinical Utility of Carbohydrate Breath Tests in Unexplained GI Symptoms

Conditions
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Small Intestinal Bacterial Overgrowth, Lactose Intolerance, Fructose Intolerance, Glucose Intolerance

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients over the age of 18 Unexplained GI symptoms (gas, bloating, diarrhea, fullness, belching, and abdominal pain) Patients who have had normal blood tests and colonoscopy, normal CT or ultrasound scan of the abdomen Patients who have completed at least one breath test Exclusion Criteria: Patients with previous GI surgeries (except cholecystectomy, hysterectomy, Nissen funduplication and appendectomy) Significant comorbid medical problems (congestive heart failure, chronic renal failure, respiratory failure) Cancer History of recent antibiotic use (4 weeks)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| small intetsinal bacterial overgrowth<br>Glucose breath test, 75 g glucose in 250 ml water. Breath samples collected at baseline and every 15 min for 2 hours | |
| Fructose breath Test<br>Fructose breath test, 25 g fructose in 250 ml water. Breath samples collected at baseline and every 30 min for 3 hours | |
| Lactose Breath test<br>Lactose breath test, 25 g lactose in 250 ml water. Breath samples collected at baseline and every 30 min for 5 hours | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Small Intestinal Bacterial Overgrowth | bacterial overgrowth which results in the inability to absorb nutrients | 3 hour test | 
| Positive Breath test | significant increase in the level of Hydrogen greater than or equal to 20ppm or methane greater than or equal to 15ppm or both above greater than or equal to 15ppm baseline. | 3 hour test | 
| Malabsorption | significant rise in hydrogen and/or methane levels | 3 hour test | 
| Intolerance | both the presence of malabsorption and the onset of new symptom or an increase (greater than or equal to 1) in the severity of baseline symptoms | 3 hour test | 
| Normal test | absence of GI symptoms or change in symptoms during the test together with no significant increase in the levels of hydrogen and methane. | 3 hour test | 
| hypersensitivity | significant increase (greater than or equal to 1) in the severity of two or more baseline symptoms together with no significant rise in hydrogen or methane levels | 3 hour test | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Breath test, SIBO, GI