ORLANDO — A short survey that assesses compliance with a gluten-free diet among adults with celiac disease has been validated.
Scores on the Celiac Dietary Adherence Test corresponded better with an independent dietician's assessment of adherence than the standard serum test, the IgA tissue transglutaminase titer, according to a comparison among 200 people with biopsy-proven celiac disease.
Celiac disease affects up to 1% of the general population worldwide (Nutr. Clin. Care 2005;8:54–69). Its increasing prevalence is outpacing the number of adequately trained dieticians. This survey may be especially useful in areas where access to such a dietician is limited, said Dr. Daniel Leffler, director of clinical research at the Celiac Center, Beth Israel Deaconess Medical Center, Boston. He presented results at the annual meeting of the American College of Gastroenterology.
An expert panel of gastroenterologists, dieticians, and psychologists, as well as focus panels of people with celiac disease, created an initial 80-item survey. They agreed on factors in five domains: symptoms, perceived adherence, reasons for adherence, self-efficacy, and disease-specific knowledge.
An initial cohort of 150 patients completed the survey and had IgA tissue transglutaminase titers measured. The survey was then pared down to 40 items and administered to a second cohort of 50 others with celiac disease to confirm its validity. This process resulted in a seven-item survey with 89% accuracy in predicting gluten-free diet adherence, Dr. Leffler said.
The Celiac Dietary Adherence Test asks patients to respond to the following questions and statements and uses a table to rate the responses and obtain a total score that reflects the likelihood of adherence to the gluten-free diet:
▸ Have you been bothered by low energy level during past 4 weeks?
▸ Have you been bothered by headaches during the past 4 weeks?
▸ I am able to follow a gluten-free diet when dining outside my home.
▸ Before I do something I carefully consider the consequences.
▸ I do not consider myself a failure.
▸ How important to your health are accidental gluten exposures?
▸ Over the past 4 weeks how many times have you eaten foods containing gluten on purpose?
The score on the tool highly correlated with dietician evaluation at 3 months: 0.771 among the first cohort of patients and 0.764 among the second group (using a Pearson's correlation coefficient area under the curve calculation).
The IgA tissue transglutaminase assay, in contrast, correlated less with the dietician's evaluation, at 0.647. Dr. Leffler commented, “serologic tests are generally good for diagnosis, but unfortunately, few lines of testing suggest they're as good for ongoing monitoring.”