SAN DIEGO – Visceral hypersensitivity may be an independent contributor to gastrointestinal symptoms in patients with functional GI disorders, a study showed.
The association was independent of the subjects’ tendency to report non-GI symptoms and independent of psychological distress.
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“We found a gradual increase in GI symptom severity related to hypersensitivity tertiles in irritable bowel syndrome and dyspepsia, and small but significant correlations between pain/discomfort thresholds and GI symptom severity across several large patient groups from different countries,” said presenting author Dr. Magnus Simren. “This association was independent of the tendency to report GI symptoms or comorbid anxiety and depression.”
The relationship between visceral hypersensitivity and GI symptoms has been questionable, with some studies suggesting an association between visceral hypersensitivity and symptom severity and pain in irritable bowel syndrome (IBS), dyspepsia, and other GI disorders.
However, some negative studies have failed to confirm this association, explained Dr. Simren. “The thinking is that reporting GI symptoms and severity of symptoms may reflect a general tendency to report symptoms that [are] explained by comorbid psychological stress,” he noted.
The study Dr. Simren presented at the annual Digestive Disease Week sought to determine the association between visceral hypersensitivity and GI symptoms and symptom severity, adjusted for psychological distress (anxiety and depression) as well as a tendency to report symptoms.
The study enrolled five patient cohorts with functional GI disorders at three different centers. Subjects underwent balloon distension (a validated method to determine GI hypersensitivity) and completed questionnaires to assess GI symptom severity, somatization, anxiety, and depression.
The five cohorts were the Belgian functional dyspepsia cohort (n = 242), IBS cohort 1 in the United States (n = 243), U.S. IBS cohort 2 (n = 159), Swedish IBS cohort 1 (n = 353), and Swedish IBS cohort 2 (n = 147). Subjects were divided into sensitivity tertiles based on pain/discomfort thresholds.
Dr. Simren pointed out that the three different countries used questionnaires with subtle differences to measure GI symptoms, anxiety, and depression. Therefore, the total scores of all GI questionnaires were recalculated to z scores for comparisons.
The barostat protocols also differed among the three countries, and different pain thresholds were used, he noted.
For statistical analysis, sensitivity tertiles (low, medium, and high) were constructed based on pain/discomfort thresholds. GI symptom severity was compared between tertiles and adjusted for anxiety and depression as well as for non-GI symptom reporting.
Then GI hypersensitivity (high and low thresholds) was correlated with symptom severity total scores and pain/discomfort thresholds. Significant differences in GI symptom severity were found between high and low threshold hypersensitivity tertiles across all five cohorts. These differences remained after investigators controlled for the presence of anxiety or depression. The same association was seen when investigators controlled for reporting of non-GI symptoms.
Dr. Simren acknowledged that these barostat tests are used in a research setting. “But you can use this information in managing patients. We would need a simpler test for clinical utility,” he said.
“These findings confirm that visceral hypersensitivity is a contributor to symptom generation in functional GI disease,” Dr. Simren said.