Celiac Rates Four Times Higher Among Irritable Bowel Syndrome Sufferers
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Prior studies have indicated that people with IBS had higher rates of celiac disease, but evidence has not been clear, and medical guidelines do not always call for celiac screening in these individuals.
To determine rates of celiac disease in random adults meeting clinical criteria for IBS, the research team reviewed MEDLINE from 1950 to May 31, 2008, and EMBASE from 1980 to May 31, 2008. They isolated case series and case-control studies that contained data for celiac disease blood screens. They found 14 such studies.
From each study, they isolated and aggregated positive serologic test results for celiac disease and biopsy-proved celiac disease. They then compared the data to that for patients with IBS and control individuals, using an odds ratio (OR) and 95% confidence interval (CI).
The team isolated 4204 suitable cases from the identified studies. Of those, 2278 met clinical criteria for IBS (54%). The overall rate of positive immunoglobulin A (IgA)–class antigliadin antibodies (AGA) was 4.0% (95% CI, 1.7% – 7.2%), the rate of positive endomysial antibodies (EMA) was 1.63% (95% CI, 0.7% – 3.0%), and the rate of tissue transglutaminase (tTGA) was 4.1% (95% CI, 1.9% – 7.0%). For biopsy-proven celiac disease, the overall rate was 4.1% (95% CI, 1.9% – 7.0%).
In patients who met the clinical criteria for IBS compared with non-IBS control subjects, aggregate OR for positive IgA-class antigliadin antibodies was 3.40 (95% CI, 1.62 – 7.13), aggregate OR for either positive EMA or tTGA was 2.94 (95% CI, 1.36 – 6.35), and aggregate OR for biopsy-proved celiac disease was 4.34 (95% CI, 1.78 – 10.6).
The study did have some weaknesses, including issues with the methodology governing study selection, possible spectrum bias in case-control studies, possible selection bias in studies based in secondary care, and, in some cases, results too limited to allow meaningful aggregation of data.
Still the research team concludes that rates of biopsy-proven celiac disease are more than four times higher for IBS patients than for non-IBS controls. The team recommends that, if screening is undertaken, EMA or tTGA testing be used in lieu of IgA-AGA testing due to their higher positive predictive value, though they admitted that results will depend on celiac rates in the population being screened.
The study was supported by the American College of Gastroenterology.
Arch Intern Med. 2009;169:651–658.
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