Efficacy of a Gluten-Free Diet in Subjects With Irritable Bowel Syndrome-Diarrhea Unaware of Their HLA-DQ2/8 Genotype

• Published in: Clinical gastroenterology and hepatology Vol. 14; no. 5; pp. 696 - 703.e1
• Main Authors: Aziz, Imran, Trott, Nick, Briggs, Rebecca, North, John R., Hadjivassiliou, Marios, Sanders, David S.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.2016
• Subjects: Adult; Carbohydrates; Clinical Trial; Diarrhea - therapy; Diet, Gluten-Free; Female; Food; Gastroenterology and Hepatology; Gastrointestinal Symptoms; Genotype; HLA-DQ Antigens - genetics; Humans; Irritable Bowel Syndrome - therapy; Male; Middle Aged; Prospective Studies; Severity of Illness Index; Surveys and Questionnaires; Treatment Outcome; United Kingdom; Carbohydrates; CD; Clinical Trial; GFD; HADS; Gastrointestinal Symptoms; IBS-SSS; QOL; SF-36; FIS; IBS-D; IBS; Food; Fatigue Impact Scale; gluten-free diet; irritable bowel syndrome; irritable bowel syndrome with diarrhea; Short Form-36; Irritable Bowel Syndrome–Symptom Severity Score; Hospital Anxiety and Depression Scale; celiac disease; quality of life
• ISSN: 1542-3565; 1542-7714; 1542-7714
• DOI: 10.1016/j.cgh.2015.12.031

A gluten-containing diet alters bowel barrier function in patients with irritable bowel syndrome with diarrhea (IBS-D), particularly those who are positive for HLA allele DQ2/8. We studied the effects of a gluten-free diet (GFD) in patients with IBS-D who have not previously considered the effects of gluten in their diet and were unaware of their HLA-DQ2/8 genotype. We performed a prospective study of 41 patients with IBS-D (20 HLA-DQ2/8-positive and 21 HLA-DQ2/8-negative) at the Royal Hallamshire Hospital in Sheffield, United Kingdom, from September 2012 through July 2015. All subjects were placed on a 6-week GFD following evaluation by a dietician. Subjects completed validated questionnaires at baseline and Week 6 of the GFD. The primary endpoint was mean change in IBS Symptom Severity Score; a 50-point reduction was considered to indicate a clinical response. Secondary endpoints were changes in hospital anxiety and depression score, fatigue impact score, and Short Form-36 results. Clinical responders who chose to continue a GFD after the study period were evaluated on average 18 months later to assess diet durability, symptom scores, and anthropometric and biochemical status. A 6-week GFD reduced IBS Symptom Severity Score by ≥50 points in 29 patients overall (71%). The mean total IBS Symptom Severity Score decreased from 286 before the diet to 131 points after 6 weeks on the diet (P < .001); the reduction was similar in each HLA-DQ group. However, HLA-DQ2/8-negative subjects had a greater reduction in abdominal distention (P = .04). Both groups had marked mean improvements in hospital anxiety and depression scores, fatigue impact score, and Short Form-36 results, although HLA-DQ2/8-positive subjects had a greater reduction in depression score and increase in vitality score than HLA-DQ2/8-negative subjects (P = .02 and P = .03, respectively). Twenty-one of the 29 subjects with a clinical response (72%) planned to continue the GFD long term; 18 months after the study they were still on a GFD, with maintained symptom reductions, and demonstrated similar anthropometric and biochemical features compared with baseline. A dietitian-led GFD provided sustained benefit to patients with IBS-D. The symptoms that improved differed in magnitude according to HLA-DQ status. Clinical trials.gov no: NCT02528929.