MONTREAL — Several noninvasive tests used in combination may be a more sensitive method for monitoring celiac disease activity and patient compliance with the gluten-free diet than are current approaches.
At Canadian Digestive Diseases Week, Dr. Alaa Rostom said that the majority of his celiac disease patients make every effort to avoid gluten, but hidden sources of this protein—found in wheat, rye, and barley—are often responsible for persistent symptoms. Dr. Rostom, from the University of Calgary (Alta.), presented his research in a poster at the meeting.
“The gold standard for diagnosis is positive serology and a consistent biopsy. But once a gluten-free diet is started, it takes large dietary indiscretions to turn the serology positive again,” he said.
Dr. Rostom polled a celiac disease expert panel regarding the accuracy of various noninvasive tests for monitoring disease activity and dietary adherence. The experts were asked to rank their top six tests, and tests were included in a final list if they were ranked by more than 50% of panel members. Univariate analysis revealed that the use of serology, the lactulose/mannitol test for intestinal permeability, body mass index, triceps skinfold thickness, the gastrointestinal symptom rating score (GSRS), and a quality of life measure were all considered useful by panel members.
Dr. Rostom then calculated the sensitivity and specificity of the various tests based on a retrospective data set of about 200 patients. “Serology has important sensitivity, about 90%, but the specificity is less than 90%, which explains why it won't detect small amounts of gluten exposure,” he said. “On the other hand, the lactulose/mannitol test isn't very sensitive but it has a pretty high specificity.” Therefore, combining results from both of these tests proved more useful than relying on either one alone, and yielded both a sensitivity of 92% and a specificity of 92%, which is comparable to results obtained from intestinal biopsy, he explained.
By using these results, Dr. Rostom compiled the Celiac Disease Activity Scoring System (CeDARS), which is now being validated in two randomized controlled trials. “I think probably the best assessment will likely come from combining serology, plus the lactulose/mannitol test, plus GSRS,” he suggested, pointing out that the beauty of this particular combination of tests is that it can capture different stages of response to gluten exposure.
Dr. Rostom emphasized that the goal of CeDARS is not to replace, but rather to enhance annual serology, which is currently recommended for monitoring celiac disease patients.