Study data published in Gut suggest that while confocal laser endomicroscopy (CLE) can be used to identify wheat sensitivity in patients with irritable bowel syndrome (IBS), its diagnostic sensitivity is too low to recommend widespread use. Investigators advised against CLE as a first-line diagnostic tool and instead suggested an 8-week gluten-free diet (GFD) trial period.
A significant proportion of patients with IBS may be wheat sensitive even in the absence of celiac disease. By generating high-resolution images of the gastrointestinal tract, CLE can be used to identify reactions to certain food antigens, including wheat. To test the diagnostic utility of CLE for wheat sensitivity, investigators conducted a prospective, double-blind diagnostic study of patients fulfilling the Rome III criteria for IBS. Patients with celiac disease were excluded.
At baseline, patients were tested by CLE for duodenal changes after exposure to wheat, soy, yeast, and milk. After the test, patients received dietary counseling and were started on an 8-week GFD. After 8 weeks, CLE results were unblinded and patients were advised to avoid food components that led to a positive reaction during their CLE.
Patient symptoms were re-evaluated at 6- and 12-month follow-up visits. The diagnostic accuracy of CLE was evaluated by comparing the proportion of patients who responded to an elimination diet to the proportion of patients who displayed a positive reaction on CLE. The goal diagnostic accuracy values were 80%.
A total of 147 patients were enrolled, among whom 113 (77%) were women. Mean age was 35.7±9.9 years. A total of 130 patients completed the study per protocol, of whom 74 (56.9%) responded to the 8-week GFD and were classified as having wheat sensitivity. Baseline CLE correctly classified 38 of these 74 patients, resulting in a diagnostic sensitivity of 51.4% (97.5% CI, 38.7%-63.9%). A total of 38 of 56 patients without wheat sensitivity were correctly identified by CLE (specificity, 67.9%; 97.5% CI, 52.9%-79.9%).
At the 6-month follow-up visit, 70.2% of patients responded to the dietary intervention that excluded CLE-reactive foods. At 12 months, this proportion increased to 76.1%. The sensitivity of CLE for identifying reactions to wheat, soy, yeast, or milk was 83.1% (97.5% CI, 69.9%-91.3%) at 6 months and 82.1% (97.5% CI, 69.5%-90.2%) at 12 months. Even so, significant proportions of CLE-negative patients were also found to be food sensitive at 6 months (55.6%) and 12 months (63.2%), resulting in low specificity.
While CLE correctly identified food sensitivities in a number of patients, its sensitivity and specificity were unsatisfactory. “CLE cannot currently be recommended as an initial diagnostic test in patients with IBS suspicious of having [wheat sensitivity],” investigators wrote. “Nevertheless, CLE may help to further elucidate the underlying pathomechanism contributing to mucosal and submucosal changes during food-induced alterations in the gastrointestinal tract. A rather practical approach with an 8-week GFD period may be more beneficial to patients with IBS.”
Disclosure: Several study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Bojarski C, Tangermann P, Barmeyer C, et al. Prospective, double-blind diagnostic multicentre study of confocal laser endomicroscopy for wheat sensitivity in patients with irritable bowel syndrome. Gut. Published online September 20, 2021. doi: 10.1136/gutjnl-2021-325181