Determinants and Trends of Adherence to a Gluten-Free Diet in Adult Celiac Patients on a Long-term Follow-up (2000-2020)

BACKGROUND & AIMS: Data on factors governing long-term adherence to a gluten-free diet (GFD) in celiac disease (CD) are scarce. We aimed to determine trends and clinical predictors of long-term GFD adherence in adult CD.METHODS: Initial and long-term (>3 years) GFD adherence, clinical characteristics at baseline and followup were collected retrospectively from celiac patients followed-up over 20 years (2000-2020). Predictors of long-term GFD adherence at diagnosis, and follow-up were evaluated by multivariate logistic regression.RESULTS: 248 patients (37 +/- 12 years, 186F, median time on a GFD 90 months) were included. Twentyfive (10.1%) had only short-term follow-up (<3 years) while 223 (89.9%) had initial and longterm dietary assessment. 187/223 (83.9%) patients were initially adherent and 36/223 (16.1%) were not. 17/36 (47.2%) patients initially not adherent become adherent, while only 4/187 (2.1%) initially adherent patients became not adherent. In the long-term, 200/223 (89.7%) were adherent and 21/223 (9.4%) patients were not. Adherence improved more frequently than worsened (OR, 39.5; 95% CI, 11.4-178.5; P < .01). Classical symptoms (diarrhea, weight loss) at diagnosis of CD predicted stricter long-term GFD adherence (OR, 3.27; 95% CI, 1.21-8.81; P = .02), while anemia (OR, 0.31; 95% CI, 0.12-0.82; P = .02) and dermatitis herpetiformis (OR, 0.23; 95% CI, 0.06-0.91; P = .04) predicted poorer long-term adherence. At follow-up, initial GFD adherence (OR, 42.70; 95% CI, 10.70-171.00; P = .04) was the major determinant of long-term GFD adherence.CONCLUSIONS: GFD adherence changes over time in <10% of patients, generally improving when it does. Major determinants of long-term GFD adherence are classical symptoms at diagnosis and initial adherence to a GFD. Patients with anemia or dermatitis herpetiformis at diagnosis require stricter dietetic input.