A new approach to coeliac disease diagnosis?

It is well-established that UK endoscopy services are under pressure, with post-Covid waiting lists pushing demand to an all-time high.1 Whilst a no-biopsy approach has been advocated in the diagnosis of coeliac disease (CD) in children since 2012, British Society of Gastroenterology (BSG) guidelines issued in 2014 still advise four duodenal biopsies for the diagnosis of adult CD, including one biopsy from the duodenal bulb. Emergency guidance was issued by the BSG during the Covid-19 pandemic, suggesting that patients under the age of 55 with an anti-tissue transglutaminase antibody (TGA) greater than 10 times the upper limit of normal (ULN) should be treated as having CD without the need for biopsy – an approach already followed in some countries, including Finland. A recently published study examines the evidence for this as an ongoing strategy for adult CD diagnosis, using retrospective data from Scotland.2,3

There were 1429 patients in Scotland with positive coeliac serology in the period dating from 2016. 1037 patients (72.6%) proceeded to endoscopy and biopsy, suggesting a significant attrition rate at this point in the diagnostic pathway. Frailty, co-morbidity, and patients declining the procedure were the most commonly recorded reasons for not performing endoscopy, although no information was available as to why there was no endoscopy performed in the majority of this cohort. 796 patients (76.8%) who underwent biopsy were diagnosed with CD, but sampling of the duodenal bulb was only performed in 19%, indicating that this part of the current guidelines is rarely adhered to in routine practice.

324 patients with a TGA level >/=10x ULN had a biopsy. Of these, 320 (98.7%) were diagnosed as CD, conferring a positive predictive value of 99.4% for a TGA elevated to this degree. At lower TGA levels, however, the diagnosis is much less certain, with CD only diagnosed in 66.8%. One concern about not routinely performing endoscopy for diagnosis is the potential to miss co-existent gastrointestinal pathology. However, only one patient of 1037 biopsied was found to have a tumour at upper GI endoscopy. The patient was 55 years of age and was symptomatic with abdominal pain, loose stools and bloating, so would have been appropriately excluded from a no-biopsy diagnostic pathway.

This real-world study, therefore, suggests that treating a TGA of =/> 10x ULN as diagnostic of CD in IgA-sufficient adults under the age of 55 is a safe and robust approach, with the group estimating that around a third of new positive cases could be diagnosed without endoscopy.2 Although the majority of patients presenting with a positive TGA will still require a diagnostic endoscopy, this is likely to result in a significant reduction in the diagnostic endoscopy burden nationally, as well as being acceptable to patients.

With a rising incidence,4 we need to ensure that all aspects of CD services are streamlined and fit for purpose. Attempts have been made to modernise CD follow-up, with evidence that telephone clinics can help patients adhere to a gluten-free diet.5 However, attempts to move to a model of GP-led follow-up can lead to a complete loss to follow-up, with uncertainty about the long-term implications of discharging this cohort from secondary care.6

References:

  1. Penman ID. National endoscopy services: Reflections on the impact of COVID-19. Frontline Gastroenterol. 2022. doi:10.1136/FLGASTRO-2022-102202
  2. Hoyle A, Gillett P, Gillett HR, et al. No-biopsy strategy for coeliac disease is applicable in adult patients: a ‘real-world’ Scottish experience. Frontline Gastroenterol. August 2022. doi:10.1136/FLGASTRO-2022-102254
  3. Holmes G. No-biopsy approach to the diagnosis of coeliac disease. Frontline Gastroenterol. September 2022:flgastro-2022-102305. doi:10.1136/FLGASTRO-2022-102305
  4. Stroud C, Almilaji O, Nicholas D, et al. Evolving patterns in the presentation of coeliac disease over the last 25 years. Frontline Gastroenterol. 2020;11(2):98-103. doi:10.1136/FLGASTRO-2018-101170
  5. Muhammad H, Reeves S, Ishaq S, Mayberry JF, Jeanes YM. Telephone clinic improves gluten-free dietary adherence in adults with coeliac disease: Sustained at 6 months. Frontline Gastroenterol. 2020;0:1-7. doi:10.1136/flgastro-2020-101643
  6. Pritchard L, Waters C, Murray IA, Bebb J, Lewis S. Comparing alternative follow-up strategies for patients with stable coeliac disease. Frontline Gastroenterol. 2020;11(2):93-97. doi:10.1136/FLGASTRO-2018-101156

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