Irritable bowel syndrome did not increase the likelihood of having serologic markers of celiac disease, according to a study of more than 3,000 residents of Southeastern Minnesota reported in the November issue of Clinical Gastroenterology and Hepatology.
Although several current guidelines list IBS as a risk factor for celiac disease, “our results suggest that testing for celiac disease [CD] in IBS will not have a significantly increased yield over population-based serologic screening,” said Dr. Rok Seon Choung of the Mayo Clinic, Rochester, Minn., and his associates. “In terms of IBS and other major GI syndromes, undetected CD does not appear to be positively associated with GI symptoms in the United States community.”
Despite widely available screening tests for CD, at least 80% of cases go undiagnosed. Testing based only on the presence of malabsorptive signs and symptoms misses many cases because of the trend toward “nonclassic” CD, said the researchers. “Physicians are especially likely to encounter patients with CD who have no classic symptoms while investigating other GI disorders,” they noted. “We aimed to determine whether positive results of serologic testing for CD by using a highly sensitive and specific assaywere associated with IBS and other functional gastrointestinal disorders in a large representative U.S. white population” (Clin Gastroenterol Hepatol. 2015 May doi: 10.1016/j.cgh.2015.05.014).
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The investigators sent validated self-report bowel disease questionnaires to randomly chosen adults living in Olmsted County in Southeastern Minnesota. They also performed CD testing on serum from a convenience sample of 47,000 county residents with no prior diagnosis of CD. In all, 3,202 subjects completed questionnaires and had serum available for testing. About 55% of this group reported at least one GI symptom (95% confidence interval, 53%-57%), while 13.6% met criteria for IBS (95% CI, 12%-15%), the researchers said. A total of 1% of respondents had serologic markers for CD (95% CI, 0.7%-1.4%), in keeping with other epidemiologic studies in the United States, they added.
Notably, IBS affected only 3% of CD patients, compared with 14% of patients without CD, although the difference was not statistically significant (OR, 0.2; 95% CI, 0.03-1.5), the investigators said. Seropositive CD patients most often reported abdominal pain, constipation, weight loss, and dyspepsia, but none of these GI symptoms and no functional GI disorders were significantly more prevalent in CD patients than in non-CD patients. “These results may have important management and screening implications,” said the researchers. “Cost-effectiveness data suggest that testing for CD in patients with diarrhea-predominant IBS has an acceptable cost when the prevalence is above 1%, and becomes the dominant strategy when the prevalence exceeds 8%. However, we cannot confirm whether CD testing is a cost-effective approach in our population.”
The findings should be generalizable to white Americans, but not to the U.S. population as a whole because most participants were white, the researchers noted. “The prevalence of CD may vary by ethnic group, but the disease has been shown to be more common in whites than in other races,” they added. Responder bias was also possible, but past studies of the same bowel disease questionnaire uncovered no significant differences in rates of GI symptoms between responders and nonresponders, they noted.
The National Institutes of Health funded part of the work. Coauthor Dr. Nicholas Talley reported having colicensed the questionnaire used in the study. The remaining authors disclosed no financial conflicts.