Alimentary Pharmacology and Therapeutics
Letters to the Editors Letter: nonresponsive coeliac disease and evaluation of the strictness of a gluten-free diet C. Matuchansky Lariboisiere St-Louis Faculty of Medicine, Paris Diderot University, Paris, France. E-mail: [email protected] doi:10.1111/apt.12687
SIRS, I read with interest the article by Spatola et al.1 who identified and validated deamidated gliadin peptide IgG assays as an effective non-invasive serum biomarker of nonresponsive coeliac disease while on a gluten-free diet (GFD). I have two main concerns regarding their results. First, the evaluation of the GFD strictness. Using a detailed dietary analysis with a 4-day estimated food record, they state that all nonresponsive coeliac disease patients had strict GFD adherence. Two arguments suggest that gluten transgressions in some of their coeliac disease patients cannot be formally excluded. Firstly, diets show seasonal differences:2, 3 with reference to extensive 16-day (four 4-day) weighed food record (WFR) over 1 year, the 7-day estimated food record showed, among seven dietary assessement methods, the highest correlation, particularly for nonstarch polysaccharides, of which wholemeal bread represents the main source.2 A second 7-day food record has been considered desirable to capture seasonal variations.4 Reproducibility of 3-day WFRs over 6 months was recently shown,5 but I am not aware of similar studies showing 4-day estimated (not weighed) diet-record reproducibility, especially in treated coeliac disease. Secondly, five of their 15 nonresponsive coeliac disease patients showed positive (≥5.0 U) IgA tissue transglutaminase antibodies (tTG), which highly predicts at least moderate GFD transgressions. Indeed, titres of positive tTG have been shown to correlate with transgression amounts.6 Thus, some patients may have been misclassified as nonresponsive.
Second, the refractory coeliac disease (RCD) patient classification. Nine of their 15 nonresponsive coeliac disease patients had true (n = 4) or latent (n = 5) RCD. Why their six other asymptomatic nonresponsive coeliac disease patients were not similarly classified as latent RCD is not clear, as these six showed both strict longterm GFD adherence and persistent villous atrophy, and symptoms are not part of the criteria for latent RCD.7, 8 This could explain why they found no difference in tTG titres between the nine RCD and six remaining patients with nonresponsive coeliac disease.
ACKNOWLEDGEMENT Declaration of personal and funding interests: None. REFERENCES 1. Spatola BN, Kaukinen K, Collin P, M€aki M, Kagnoff MF, Daugherty PS. Persistence of elevated deamidated gliadin peptide antibodies on a gluten-free diet indicates nonresponsive coeliac disease. Aliment Pharmacol Ther 2014; 39: 407–17. 2. Bingham SA, Gill C, Welch A, et al. Comparison of dietary assessment methods in nutritional epidemiology: weighed records v. 24 h recalls, food-frequency questionnaires and estimated-diet records. Br J Nutr 1994; 72: 619–43. 3. Leatherdale ST. Laxer RE Reliability and validity of the weight status and dietary intake measures in the COMPASS questionnaire: are the self-reported measures of body mass index (BMI) and Canada’s food guide servings robust? Int J Behav Nutr Phys Act 2013; 10: 42. 4. Jain M, Geoffrey R, Howe GR, Rohan T. Dietary assessment in epidemiology: Comparison of a food frequency and a diet history questionnaire with a 7-day food record. Am J Epidemiol 1996; 143: 953–60. 5. Collins CE, Boggess MM, Watson JF, et al. Reproducibility and comparative validity of a food frequency questionnaire for Australian adults. Clin Nutr 2013; doi: 10.1016/j.clnu.2013.09.015 [Epub ahead of print]. 6. Vahedi K, Mascart F, Mary J-Y, et al. Reliability of antitrans glutaminase antibodies as predictors of gluten-free diet compliance in adult celiac disease. Am J Gastroenterol 2003; 98: 1079–87. 7. Kaukinen K, Per€aaho M, Lindfors K, et al. Persistent small bowel mucosal villous atrophy without symptoms in coeliac disease. Aliment Pharmacol Ther 2007; 25: 1237–45. 8. Rubio-Tapia A, Murray JA. Classification and management of refractory coeliac disease. Gut 2010; 59: 547–57.
AP&T invited commentary and correspondence columns are restricted to letters discussing papers that have been published in the journal. A letter must have a maximum of 300 words, may contain one table or figure, and should have no more than 10 references. It should be submitted electronically to the Editors via http://mc.manuscriptcentral.com/apt.
ª 2014 John Wiley & Sons Ltd
1241
Letters to the Editors Letter: nonresponsive coeliac disease and evaluation of the strictness of a gluten-free diet C. Matuchansky Lariboisiere St-Louis Faculty of Medicine, Paris Diderot University, Paris, France. E-mail: [email protected] doi:10.1111/apt.12687
SIRS, I read with interest the article by Spatola et al.1 who identified and validated deamidated gliadin peptide IgG assays as an effective non-invasive serum biomarker of nonresponsive coeliac disease while on a gluten-free diet (GFD). I have two main concerns regarding their results. First, the evaluation of the GFD strictness. Using a detailed dietary analysis with a 4-day estimated food record, they state that all nonresponsive coeliac disease patients had strict GFD adherence. Two arguments suggest that gluten transgressions in some of their coeliac disease patients cannot be formally excluded. Firstly, diets show seasonal differences:2, 3 with reference to extensive 16-day (four 4-day) weighed food record (WFR) over 1 year, the 7-day estimated food record showed, among seven dietary assessement methods, the highest correlation, particularly for nonstarch polysaccharides, of which wholemeal bread represents the main source.2 A second 7-day food record has been considered desirable to capture seasonal variations.4 Reproducibility of 3-day WFRs over 6 months was recently shown,5 but I am not aware of similar studies showing 4-day estimated (not weighed) diet-record reproducibility, especially in treated coeliac disease. Secondly, five of their 15 nonresponsive coeliac disease patients showed positive (≥5.0 U) IgA tissue transglutaminase antibodies (tTG), which highly predicts at least moderate GFD transgressions. Indeed, titres of positive tTG have been shown to correlate with transgression amounts.6 Thus, some patients may have been misclassified as nonresponsive.
Second, the refractory coeliac disease (RCD) patient classification. Nine of their 15 nonresponsive coeliac disease patients had true (n = 4) or latent (n = 5) RCD. Why their six other asymptomatic nonresponsive coeliac disease patients were not similarly classified as latent RCD is not clear, as these six showed both strict longterm GFD adherence and persistent villous atrophy, and symptoms are not part of the criteria for latent RCD.7, 8 This could explain why they found no difference in tTG titres between the nine RCD and six remaining patients with nonresponsive coeliac disease.
ACKNOWLEDGEMENT Declaration of personal and funding interests: None. REFERENCES 1. Spatola BN, Kaukinen K, Collin P, M€aki M, Kagnoff MF, Daugherty PS. Persistence of elevated deamidated gliadin peptide antibodies on a gluten-free diet indicates nonresponsive coeliac disease. Aliment Pharmacol Ther 2014; 39: 407–17. 2. Bingham SA, Gill C, Welch A, et al. Comparison of dietary assessment methods in nutritional epidemiology: weighed records v. 24 h recalls, food-frequency questionnaires and estimated-diet records. Br J Nutr 1994; 72: 619–43. 3. Leatherdale ST. Laxer RE Reliability and validity of the weight status and dietary intake measures in the COMPASS questionnaire: are the self-reported measures of body mass index (BMI) and Canada’s food guide servings robust? Int J Behav Nutr Phys Act 2013; 10: 42. 4. Jain M, Geoffrey R, Howe GR, Rohan T. Dietary assessment in epidemiology: Comparison of a food frequency and a diet history questionnaire with a 7-day food record. Am J Epidemiol 1996; 143: 953–60. 5. Collins CE, Boggess MM, Watson JF, et al. Reproducibility and comparative validity of a food frequency questionnaire for Australian adults. Clin Nutr 2013; doi: 10.1016/j.clnu.2013.09.015 [Epub ahead of print]. 6. Vahedi K, Mascart F, Mary J-Y, et al. Reliability of antitrans glutaminase antibodies as predictors of gluten-free diet compliance in adult celiac disease. Am J Gastroenterol 2003; 98: 1079–87. 7. Kaukinen K, Per€aaho M, Lindfors K, et al. Persistent small bowel mucosal villous atrophy without symptoms in coeliac disease. Aliment Pharmacol Ther 2007; 25: 1237–45. 8. Rubio-Tapia A, Murray JA. Classification and management of refractory coeliac disease. Gut 2010; 59: 547–57.
AP&T invited commentary and correspondence columns are restricted to letters discussing papers that have been published in the journal. A letter must have a maximum of 300 words, may contain one table or figure, and should have no more than 10 references. It should be submitted electronically to the Editors via http://mc.manuscriptcentral.com/apt.
ª 2014 John Wiley & Sons Ltd
1241
