Defining the optimum strategy for identifying adults and children with coeliac disease: systematic review and economic modelling

BACKGROUND

Coeliac disease is an autoimmune disorder triggered by ingesting gluten. It affects approximately 1% of the UK population, but only one in three people is thought to have a diagnosis. Untreated coeliac disease may lead to malnutrition, anaemia, osteoporosis and lymphoma.

OBJECTIVES

The objectives were to define at-risk groups and determine the cost-effectiveness of active case-finding strategies in primary care.

DESIGN

(1) Systematic review of the accuracy of potential diagnostic indicators for coeliac disease. (2) Routine data analysis to develop prediction models for identification of people who may benefit from testing for coeliac disease. (3) Systematic review of the accuracy of diagnostic tests for coeliac disease. (4) Systematic review of the accuracy of genetic tests for coeliac disease (literature search conducted in April 2021). (5) Online survey to identify diagnostic thresholds for testing, starting treatment and referral for biopsy. (6) Economic modelling to identify the cost-effectiveness of different active case-finding strategies, informed by the findings from previous objectives.

DATA SOURCES

For the first systematic review, the following databases were searched from 1997 to April 2021: MEDLINE® (National Library of Medicine, Bethesda, MD, USA), Embase® (Elsevier, Amsterdam, the Netherlands), Cochrane Library, Web of Science™ (Clarivate™, Philadelphia, PA, USA), the World Health Organization International Clinical Trials Registry Platform ( WHO ICTRP ) and the National Institutes of Health Clinical Trials database. For the second systematic review, the following databases were searched from January 1990 to August 2020: MEDLINE, Embase, Cochrane Library, Web of Science, Kleijnen Systematic Reviews ( KSR ) Evidence, WHO ICTRP and the National Institutes of Health Clinical Trials database. For prediction model development, Clinical Practice Research Datalink GOLD, Clinical Practice Research Datalink Aurum and a subcohort of the Avon Longitudinal Study of Parents and Children were used; for estimates for the economic models, Clinical Practice Research Datalink Aurum was used.

REVIEW METHODS

For review 1, cohort and case-control studies reporting on a diagnostic indicator in a population with and a population without coeliac disease were eligible. For review 2, diagnostic cohort studies including patients presenting with coeliac disease symptoms who were tested with serological tests for coeliac disease and underwent a duodenal biopsy as reference standard were eligible. In both reviews, risk of bias was assessed using the quality assessment of diagnostic accuracy studies 2 tool. Bivariate random-effects meta-analyses were fitted, in which binomial likelihoods for the numbers of true positives and true negatives were assumed.

RESULTS

People with dermatitis herpetiformis, a family history of coeliac disease, migraine, anaemia, type 1 diabetes, osteoporosis or chronic liver disease are 1.5-2 times more likely than the general population to have coeliac disease; individual gastrointestinal symptoms were not useful for identifying coeliac disease. For children, women and men, prediction models included 24, 24 and 21 indicators of coeliac disease, respectively. The models showed good discrimination between patients with and patients without coeliac disease, but performed less well when externally validated. Serological tests were found to have good diagnostic accuracy for coeliac disease. Immunoglobulin A tissue transglutaminase had the highest sensitivity and endomysial antibody the highest specificity. There was little improvement when tests were used in combination. Survey respondents (n = 472) wanted to be 66% certain of the diagnosis from a blood test before starting a gluten-free diet if symptomatic, and 90% certain if asymptomatic. Cost-effectiveness analyses found that, among adults, and using serological testing alone, immunoglobulin A tissue transglutaminase was most cost-effective at a 1% pre-test probability (equivalent to population screening). Strategies using immunoglobulin A endomysial antibody plus human leucocyte antigen or human leucocyte antigen plus immunoglobulin A tissue transglutaminase with any pre-test probability had similar cost-effectiveness results, which were also similar to the cost-effectiveness results of immunoglobulin A tissue transglutaminase at a 1% pre-test probability. The most practical alternative for implementation within the NHS is likely to be a combination of human leucocyte antigen and immunoglobulin A tissue transglutaminase testing among those with a pre-test probability above 1.5%. Among children, the most cost-effective strategy was a 10% pre-test probability with human leucocyte antigen plus immunoglobulin A tissue transglutaminase, but there was uncertainty around the most cost-effective pre-test probability. There was substantial uncertainty in economic model results, which means that there would be great value in conducting further research.

LIMITATIONS

The interpretation of meta-analyses was limited by the substantial heterogeneity between the included studies, and most included studies were judged to be at high risk of bias. The main limitations of the prediction models were that we were restricted to diagnostic indicators that were recorded by general practitioners and that, because coeliac disease is underdiagnosed, it is also under-reported in health-care data. The cost-effectiveness model is a simplification of coeliac disease and modelled an average cohort rather than individuals. Evidence was weak on the probability of routine coeliac disease diagnosis, the accuracy of serological and genetic tests and the utility of a gluten-free diet.

CONCLUSIONS

Population screening with immunoglobulin A tissue transglutaminase (1% pre-test probability) and of immunoglobulin A endomysial antibody followed by human leucocyte antigen testing or human leucocyte antigen testing followed by immunoglobulin A tissue transglutaminase with any pre-test probability appear to have similar cost-effectiveness results. As decisions to implement population screening cannot be made based on our economic analysis alone, and given the practical challenges of identifying patients with higher pre-test probabilities, we recommend that human leucocyte antigen combined with immunoglobulin A tissue transglutaminase testing should be considered for adults with at least a 1.5% pre-test probability of coeliac disease, equivalent to having at least one predictor. A more targeted strategy of 10% pre-test probability is recommended for children (e.g. children with anaemia).

FUTURE WORK

Future work should consider whether or not population-based screening for coeliac disease could meet the UK National Screening Committee criteria and whether or not it necessitates a long-term randomised controlled trial of screening strategies. Large prospective cohort studies in which all participants receive accurate tests for coeliac disease are needed.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42019115506 and CRD42020170766.

FUNDING

This project was funded by the National Institute for Health and Care Research ( NIHR ) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 44. See the NIHR Journals Library website for further project information.

Celiac Disease in Children with Functional Constipation: A School-Based Multicity Study

OBJECTIVE

To determine whether children in the community with functional constipation have increased prevalence of celiac disease.

STUDY DESIGN

Between April 4, 2015, and April 25, 2017, we enrolled 1809 children from 5 schools in Colombia and screened them for functional gastrointestinal disorders (FGIDs), including functional constipation, using questionnaires recommended in the Rome III/IV criteria. We matched children with functional constipation with healthy controls without a FGID and tested them for celiac disease with tissue transglutaminase (tTG)-Immunoglobulin A (IgA) and total IgA screening. In those who tested positive for tTG-IgA, we performed HLA genotyping and endoscopy to obtain 4 duodenal biopsy specimens for classification of celiac disease using the Marsh criteria. Analysis of statistical significance between groups of children with and without functional constipation was done using a 2-tailed Fisher exact test.

RESULTS

Patients diagnosed with functional constipation (n = 203) were matched with 419 healthy controls without FGIDs. The overall prevalence of celiac disease in the entire cohort was 0.6%. Of those with functional constipation, 1 (0.5%) was diagnosed with celiac disease, and 3 (0.7%) of the control patients without FGIDs had celiac disease (P = .743).

CONCLUSIONS

The prevalence of celiac disease in our cohort was similar to worldwide estimates. The prevalence of celiac disease in schoolchildren with functional constipation in Colombia is similar to those without FGIDs. Thus, routine testing of schoolchildren with functional constipation for celiac disease is not indicated.

Is celiac disease misdiagnosed in children with functional constipation?

BACKGROUND/AIMS

Functional constipation is one of the common problems in childhood, and it comprises approximately 5% of the pediatric outpatient clinical applications. On the other hand, celiac disease (CD) is an immune enteropathy with the prevalence between 1/150 and 1/200. In addition to the classical symptoms of the disease such as diarrhea and weight loss, the incidence of atypical symptoms is increasing. This study aims to determine the prevalence of CD in patients with chronic constipation.

MATERIALS AND METHODS

The study was conducted between 2010 and 2012 and included 1046 children (range, 2-18 y; median, 11.4 y) diagnosed with chronic constipation according to the Rome III criteria. Serum immunoglobulin A, tissue transglutaminase, and/or anti-endomysial antibodies were examined. The patients with serological positive results were subjected to upper gastrointestinal system endoscopy and duodenal biopsy to confirm the diagnosis of CD.

RESULTS

Blood tests were positive in 36 patients (3.25%). One of the patients had Hashimoto's thyroiditis, and 4 patients had short stature. Endoscopic findings included nodularity in bulbus and duodenal mucosa (n=16), scalloping fold (n=13), and normal mucosa (n=5). Histopathologic findings revealed that 10 patients had total villous atrophy, 24 patients had subtotal and partial villous atrophy, and 34 patients had intraepithelial lymphocyte infiltration. All patients followed a gluten-free diet, resulting in a resolution of symptoms.

CONCLUSION

In the present study, a CD ratio of 1:28 was diagnosed in chronically constipated children. The use of screening tests for CD should be considered in children with conventional treatment-resistant constipation.

ANTI-TTG AMONG CHILDREN WITH CHRONIC FUNCTIONAL CONSTIPATION UNRESPONSIVE TO 6 WEEKS OF TREATMENT OF CONSTIPATION

BACKGROUND

Celiac disease is a glutten induced enteropathy. Some authors recommended screening celiac in children with constipation. There are studies to evaluate celiac disease in children with constipation. But most of them included children regardless to treatment failure.

OBJECTIVE

The aim of this study was to evaluate frequency of elevated anti TTG in children with constipation after failure to improve during 6 week of appropriate treatment of constipation.

METHODS

In this cross sectional study, 550 children with prolonged constipation were included. Place of study was Pediatric Gastroenterology clinic of Abuzar children's hospital. Prolonged constipation was defined as a constipation which failed to resolved after 6 weeks of appropriate treatment. Constipation was defined according to ROME III criteria. After parental agreement, 5 mL of blood was obtained. Serum anti TTG level was measure using ELISA method by Orientec kit. Anti TTG>10 was considered positive if IgA was normal. SPSS version 16.0 (Chicago, IL, USA) was used for data analysis. Chi square, t-test, and Mann Whitney test used for data analysis.

RESULTS

In this study 550 children (m=277, f=273) were included. Mean age of the cases was 6.8±2.9 year. Anti TTG antibody level was 5.8±2.8 unit/mL. Of these case, 42 (7.6%) had positive anti-TTG antibody. Celiac disease was confirmed in 40 cases after histopathology examination.

CONCLUSION

Anti-TTG was positive in 7.6% children with chronic constipation who failed to respond after 6 week of treatment. Another multicenter study with longer follow up period is recommended.