A Simple Validated Gluten-Free Diet Adherence Survey for Adults With Celiac Disease

Background & Aims

Celiac disease is an increasingly prevalent disorder. To monitor response to treatment in clinical and research settings, it is essential to accurately measure gluten-free diet (GFD) adherence in a standardized manner. The aim of this study was to develop a valid and reliable Celiac Dietary Adherence Test (CDAT).

Methods

Items and domains believed to be essential for successful GFD adherence were used to develop an 85-item survey with input from patient focus groups. The survey was administered to 200 individuals with biopsy-proven celiac disease who underwent standardized dietician evaluation (SDE) and serologic testing.

Results

Of the initial 85 items, 41 were correlated highly with the SDE (P < .01). Responses for all 200 participants for the 41 items were entered into a single database. Computer-generated randomization produced a derivation cohort of 120 subjects and a validation cohort of 80. By using the derivation cohort, a 7-item questionnaire was developed using logistic regression. The additive score based on these items was correlated highly with the SDE in both the derivation and validation cohorts (P < .001) and performed significantly better than immunoglobulin A tissue transglutaminase titers in receiver operating characteristic curve analysis with areas under the curve of 0.830 and 0.652, respectively.

Conclusions

The CDAT is a clinically relevant, easily administered, 7-item instrument that allows for standardized evaluation of GFD adherence and is superior to tissue transglutaminase serology. The CDAT may be useful in both research and clinical settings.

Abbreviations used in this paper: AUC, area under the curve, BIDMC, Beth Israel Deaconess Medical Center, CD, celiac disease, CDAT, Celiac Dietary Adherence Test, GFD, gluten-free diet, Ig, immunoglobulin, ROC, receiver operator characteristic curve, SDE, standardized dietician evaluation, tTG, tissue transglutaminase