Coeliac disease: recognition, assessment and management

Approaches to testing

New evidence was identified on a range of different approaches to serological testing, including point-of-care testing, deamidated gliadin peptide testing, immunoglobulin A (IgA) anti-tissue transglutaminase antibody (IgA anti‑tTG) testing, human leukocyte antigen (HLA)‑DQ2/8 testing and combined testing. This evidence was largely consistent with guideline recommendations or required further confirmatory research to signal an impact on the guideline.

Non-biopsy strategy in young people and adults

NICE guideline NG20 advises referral of young people and adults with positive serological test results to a gastrointestinal specialist for endoscopic intestinal biopsy to confirm or rule out CD. Despite stakeholder feedback indicating the value of non-biopsy diagnosis in adults, the collective new evidence does not indicate sufficient diagnostic accuracy of this approach in adults to justify a change to the recommendations. Although no ongoing trials were identified in the surveillance review, we recognise that this is a rapidly evolving area of research and further evidence will be considered when available. We will revisit this section of the guideline when the British Society of Gastroenterology publishes its updated guidance in this area.

Non-biopsy strategy in children

NICE guideline NG20 recommends referral of children with positive serological test results to a paediatric gastroenterologist or paediatrician with a specialist interest in gastroenterology for further investigation for CD. This allows for alternative confirmatory diagnosis to biopsy in certain circumstances. These alternatives could include a non-biopsy approach by using an IgA EMA (endomysial antibodies) test to confirm serological positivity or using genetic testing. The guideline committee recognised that an endoscopic intestinal biopsy is not always available as an option in paediatric populations because it can be highly distressing for both the children and their parents and also requires additional care and costs because of the need for general anaesthetic.

Topic experts and stakeholders highlighted that a non-biopsy approach, including serological and genetic testing, to diagnose CD in children, is being used increasingly in the NHS. Non-biopsy testing is a less invasive approach, which avoids the need for endoscopy and general anaesthesia, and is considered by some topic experts to be cost saving. The European Society of Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) guidelines for diagnosing coeliac disease 2020 state that if TGA‑IgA is 10 or more times the upper limit of normal then non-biopsy diagnosis may be applied, provided IgA EMA will test positive in a second blood sample (this approach would be subject to carer or parent approval). The ESPGHAN guidelines also state that HLA DQ2‑/DQ8 determination and symptoms are not obligatory additional criteria for the non-biopsy approach. New evidence indicates that a non-biopsy approach in children has high diagnostic accuracy under the ESPGHAN criteria. This approach could avoid risks and costs of endoscopy for a significant proportion of children with suspected CD, and therefore we will revisit this section of the guideline once the British Society of Gastroenterology publishes its updated guidance in this area.

Annual monitoring

Topic experts advised on standard follow‑up serology as part of annual review, in addition to nutrition screening and the need for guidance on dual energy X‑ray absorptiometry (DEXA) scanning for osteoporosis. However, recommendation 1.4.3 in NICE guideline NG20 already advises offering annual review to include consideration of the need for assessment of diet and dietary adherence, plus the need for specialist dietetic and nutritional advice. Recommendation 1.4.4 also advises referral to a GP or consultant to assess the need for a DEXA scan for osteoporosis, and the need for specific blood tests. No new evidence was identified to signal any need for change to the existing advice.

Stakeholders also highlighted the need for more detailed advice on how adherence to a gluten-free diet should or should not be assessed at annual review. In developing the guideline, the committee noted that in their clinical experience, serological testing may inaccurately indicate non-adherence when patients have had a dietitian verify that they have ceased all gluten ingestion. For this reason, the guideline advises that serological testing should not be used alone to measure adherence.

The guideline committee highlighted, based on their own expertise and clinical experience, that people with CD benefit from regular dietetic assessment to monitor adherence to the gluten-free diet, review symptoms, and provide nutritional advice, and that this would represent a gold standard for annual review. However, there was a lack of good quality evidence to support this, and in view of the significant implementation ramifications of offering all people with CD access to a specialist dietitian, the guideline committee agreed that the recommendation should reflect that dietetic input should be considered as part of an annual review. A research recommendation was also made to stimulate investigation into the use of dietetic support as an integral component of an annual review for people with CD. The surveillance review did not identify any new evidence to inform more detailed advice to assess adherence to a gluten-free diet, or to address the research recommendation.

Stakeholders commented on the lack of guidance on serology as a marker for persistent villous atrophy. New evidence indicated that tests for serum IgA tTG and IgA EMA levels had low accuracy in monitoring CD patients for persistent villous atrophy. The evidence suggested that in the absence of these markers, signs and symptoms for this complication should be assessed at annual review and onward referral should be considered if concerns arise. This is consistent with recommendation 1.4.4 for assessing the risk of long-term complications or comorbidities.

Pneumococcal immunisation

New evidence and feedback from topic experts and stakeholders indicated a higher risk of hospital-acquired and community-acquired pneumococcal infection for people with CD, suggesting that preventive pneumococcal vaccination should be considered for these people, in addition to those with functional hyposplenism. However, vaccination guidance is set at a national level by the UK government through the Joint Committee on Vaccination and Immunisation and is not within the scope of NICE guideline NG20. New evidence identified in the current surveillance review is therefore unlikely to impact on the guideline.

Folic acid supplementation

Topic experts and stakeholders highlighted an inconsistency between the guideline, which does not advise on folic acid supplementation, and the NICE clinical knowledge summary (CKS) on coeliac disease management, which advises high-dose folic acid supplementation (5 mg once daily) for women with CD who are pregnant, or who are planning a pregnancy. The basis for this advice is that women with CD are considered at high risk of having a child with a neural tube defect. However, the CKS topic states that this is based on expert advice, rather than evidence, and what CKS considers to be good medical practice based on the potential risk of poor absorption of folic acid in women with CD. No evidence was identified to substantiate the CKS advice, which does not constitute formal NICE guidance, and until evidence indicates otherwise, no impact on the guideline is anticipated. The CKS advice will be amended to align with NICE guideline NG20. NICE's guideline on maternal and child nutrition provides further advice in this area.

Role of the dietitian

Topic experts and stakeholders asserted that the value of the dietitian should be made more prominent in both NICE guideline NG20 and NICE's quality standard on coeliac disease. The specialist knowledge and training of dietitians includes behavioural modification and counselling skills to support patients around early dietary management of CD. It was noted that there is an important role for dietitians to play in the community and that this should be reflected in the guideline. However, the role of the dietitian is already outlined in NICE guideline NG20, recommendations 1.5.1 and 1.6.2, which include referral to and information on specialist dietitians. There is also a research recommendation in this area, which remains ongoing.

Prescription of gluten-free foods

Topic experts and stakeholders highlighted a need for the guideline to recommend the prescription of gluten-free foods following changes in the legislation, the NHS (General Medical Services Contracts) (Prescription of Drugs etc.) (Amendment) Regulations 2018.

However, the guideline does not make recommendations on prescribing of gluten-free foods because policy and legislation in this area is set at a national level by the Department for Health and Social Care, with implementation passed to clinical commissioning groups at a local and regional level. Therefore, no impact is anticipated on the guideline.

Implementation issues

Stakeholders raised 2 guideline implementation issues concerning serological testing; NICE guideline NG20 recommends testing for total IgA and IgA tTG as the first-choice serological test. A stakeholder noted anecdotal evidence that the request to test for total IgA is not always automatically carried out. The guideline also advises using IgA EMA if IgA tTG is weakly positive. A stakeholder noted further anecdotal evidence that some healthcare professionals, including some secondary care settings, do not have access to EMA. These issues have been passed to the NICE system support for implementation team for further investigation.

Irritable bowel syndrome

Stakeholders highlighted that more work is needed to reduce the number of misdiagnoses of irritable bowel syndrome (IBS) in people with CD. The national charity Coeliac UK is in the process of commissioning epidemiology research, which will provide the incidence and prevalence of these conditions in the UK as of 2019. Information on prior diagnosis of IBS will also be available and preliminary prevalence figures are anticipated by May 2020. This research will help to identify key areas of underdiagnosis. This will be monitored for potential impact on NICE guideline NG20 and NICE's guideline on IBS in adults. No other evidence was identified to signal an impact in this area.

Dermatitis herpetiformis

Feedback from experts and stakeholders highlighted the absence of any reference to testing in people who have dermatitis herpetiformis in NICE guideline NG20. However, the guideline committee did not find any evidence meeting the search protocols to indicate that testing for the existence of dermatitis herpetiformis would be a reliable indicator of CD. The developers were therefore unable to include it in the list of criteria on when to offer serological testing in recommendation 1.1.1. No additional eligible evidence was identified in the 2019 surveillance review.

For further details and a summary of all evidence identified in surveillance, see appendix A.