Breath-based biomarkers identify irritable bowel syndrome

Last Updated: 2016-05-20

By Will Boggs MD

NEW YORK (Reuters Health) - A set of volatile organic compounds (VOCs) in breath distinguishes between patients with irritable bowel syndrome (IBS) and healthy controls, researchers from the Netherlands report.

"Analysis of exhaled breath is a promising tool in disease diagnosis and monitoring potentially able to rise to the challenge of IBS diagnosis," Dr. Frederik-Jan van Schooten from Maastricht University told Reuters Health by email. "We have selected a set of compounds that can serve as biomarkers but now to fully prove the usefulness of these markers multicenter and large prospective cohort studies are necessary to warrant and validate these findings."

"Previously we found diagnostic volatile metabolites in breath of patients suffering from inflammatory bowel diseases like Crohn's disease and ulcerative colitis," he said. "In the present study, we used our approach to the mild functional intestinal disorder IBS. The current diagnosis of IBS is symptom based on questionnaires, and therefore not fully objective."

Dr. van Schooten's team identified a group of 16 VOCs with best discriminatory power between IBS patients and healthy controls, they report in Alimentary Pharmacology and Therapeutics, online May 2.

This set of biomarkers yielded a sensitivity of 89.4%, a specificity of 73.3%, a positive predictive value of 84%, and a negative predictive value of 81.5% for identifying patients with IBS.

In principal component analysis, there was partial overlap between patients with IBS and healthy controls, indicating that some IBS patients have VOC profiles more similar to healthy controls and vice versa.

There was a significant correlation between these VOCs and gastrointestinal symptoms associated with IBS.

"I think what is very striking is the significant relation between volatile metabolites in breath and GI symptoms (e.g., abdominal pain or abdominal discomfort) in IBS individuals but also in subjects from (a) general-population cohort," Dr. van Schooten said. "What ought to be mentioned is that the discriminatory VOC profile was not affected by the common medical intake by the IBS patients. This might be surprising, but it means that IBS has a clear fingerprint in exhaled breath."

"Once these biomarkers are validated, development of small 'fool-proof' handheld devices, combined with advanced signal processing modules and easy-to-apply breath collection procedures, will lead to the application of breath-omics-based diagnostics in gastro-intestinal clinical practice," he concluded. "These noninvasive monitoring technologies have the potential to move medicine from a reactive treatment mode into a preventive and personalized mode facilitated by point-of-care and home-based diagnostic tools."

Dr. Per Farup from Norwegian University of Science and Technology in Trondheim, Norway, who also recently examined breath biomarkers for IBS, told Reuters Health by email, "The results show that VOC (and the microbiota) are associated with gastrointestinal function. It is unknown if the test can differentiate IBS from other functional disorders and from organic diseases."

At least for now, he said, "the procedure to perform the test seems to be too complicated for use in daily clinical practice."

SOURCE: http://bit.ly/22hZBYA

Aliment Pharmacol Ther 2016.