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Clinical Utility of Breath Tests in GI

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT03261856
Recruitment Status : Completed
First Posted : August 25, 2017
Last Update Posted : February 17, 2020
Information provided by (Responsible Party):
Augusta University

Brief Summary:
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.

Condition or disease
Small Intestinal Bacterial Overgrowth Lactose Intolerance Fructose Intolerance Glucose Intolerance

Detailed Description:

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.

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Study Type : Observational
Actual Enrollment : 1080 participants
Observational Model: Case-Only
Time Perspective: Retrospective
Official Title: Clinical Utility of Carbohydrate Breath Tests in Unexplained GI Symptoms
Actual Study Start Date : August 31, 2011
Actual Primary Completion Date : December 31, 2017
Actual Study Completion Date : December 31, 2017

small intetsinal bacterial overgrowth
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
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
Lactose breath test, 25 g lactose in 250 ml water. Breath samples collected at baseline and every 30 min for 5 hours

Primary Outcome Measures :
  1. Small Intestinal Bacterial Overgrowth [ Time Frame: 3 hour test ]
    bacterial overgrowth which results in the inability to absorb nutrients

  2. Positive Breath test [ Time Frame: 3 hour 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. Malabsorption [ Time Frame: 3 hour test ]
    significant rise in hydrogen and/or methane levels

  4. Intolerance [ Time Frame: 3 hour test ]
    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

  5. Normal test [ Time Frame: 3 hour test ]
    absence of GI symptoms or change in symptoms during the test together with no significant increase in the levels of hydrogen and methane.

  6. hypersensitivity [ Time Frame: 3 hour test ]
    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

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Patients who have had breath tests as part of routine standard of care to diagnose the unexplained GI symptoms that were abnormal results.

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)

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT03261856

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United States, Georgia
Augusta University
Augusta, Georgia, United States, 30912
Sponsors and Collaborators
Augusta University
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Principal Investigator: Satish SC Rao, MD, PhD Augusta University
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Responsible Party: Augusta University Identifier: NCT03261856    
Other Study ID Numbers: 1114725
First Posted: August 25, 2017    Key Record Dates
Last Update Posted: February 17, 2020
Last Verified: July 2018

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Augusta University:
Breath test
Additional relevant MeSH terms:
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Lactose Intolerance
Fructose Intolerance
Glucose Intolerance
Glucose Metabolism Disorders
Metabolic Diseases
Malabsorption Syndromes
Intestinal Diseases
Gastrointestinal Diseases
Digestive System Diseases
Carbohydrate Metabolism, Inborn Errors
Metabolism, Inborn Errors
Genetic Diseases, Inborn
Fructose Metabolism, Inborn Errors