TOPLINE:

Approximately 76% of patients with irritable bowel syndrome (IBS) demonstrated hypersensitivity during a lactulose nutrient challenge test, with hypersensitivity associated with more severe gastrointestinal (GI) symptoms, lower rectal pain thresholds, and increased breath hydrogen levels.

METHODOLOGY:

• The lactulose nutrient challenge test is a noninvasive method for assessing GI symptoms related to meal intake; however, there is currently no cutoff score to identify those who are hypersensitive to this test.
• Researchers enrolled participants at Sahlgrenska University Hospital in Gothenburg, Sweden, who completed the test between 2010 and 2020, which involved ingesting 25 g of lactulose and 400 mL of a nutrient drink after fasting for over 8 hours.
• GI symptom severity was rated on Likert scales every 15 minutes for 4 hours post-ingestion, and breath hydrogen and methane levels were measured concurrently.
• Five common symptoms — gas or flatulence, abdominal bloating, abdominal distension, abdominal discomfort, and abdominal pain — were rated during testing to establish a cutoff value expressed by the area under the curve (AUC). Hypersensitivity was defined as symptom AUC above the 95th percentile of healthy volunteers.
• Validated questionnaires, including the Gastrointestinal Symptom Rating Scale and the Hospital Anxiety and Depression Scale, were collected.

TAKEAWAY:

• A total of 273 patients with IBS (mean age, 35.6 years; 72% female) and 133 healthy volunteers (mean age, 31.6 years; 64% female) were included.
• Among those with IBS, 76.2% were hypersensitive to the lactulose nutrient challenge test, and 34.1% were hypersensitive across all three symptoms: gas or flatulence, abdominal bloating, and abdominal pain.
• Patients with IBS and hypersensitivity were predominantly female and reported more severe GI and psychological symptoms than those without hypersensitivity.
• Hypersensitive patients with IBS also had lower rectal pain thresholds and higher breath hydrogen levels than non-hypersensitive patients.
• More severe GI symptoms, lower rectal pain thresholds, and increased breath hydrogen levels were independently associated with hypersensitivity to the lactulose nutrient challenge test in IBS.

IN PRACTICE:

“This study highlights the usefulness of [lactulose nutrient challenge test] as a noninvasive and physiologic tool to test GI sensory function in relation to a meal,” the authors of the study wrote.

SOURCE:

The study was led by Joost P. Algera, MD, PhD, and Chloé Melchior, MD, PhD, University of Gothenburg, Gothenburg, Sweden. It was published online in The American Journal of Gastroenterology.

LIMITATIONS:

The single-center design limits generalizability to broader or more diverse IBS populations. Patients were diagnosed using different versions of the Rome criteria. Rectal sensitivity was only evaluated in one cohort. The lactulose nutrient drink used does not fully represent a typical meal.

DISCLOSURES:

The study was funded by grants from the Swedish state under the ALF agreement, the Swedish Research Council, and the Faculty of Medicine at the University of Gothenburg. Some authors reported receiving research awards, serving as a consultant or advisory board member, receiving research grants, and/or being on the speakers bureaus of several companies.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.