New guidelines on coeliac disease

Last month, NICE issued new guidelines on coeliac disease. Dr Sohail Butt examines the key points.

In May 2009, NICE published guidelines on the diagnosis and assessment of coeliac disease,1 the autoimmune condition in which children and adults develop a heightened immunological response to dietary gluten, found in wheat, barley and rye.

This article sets out the key recommendations.

Endoscopic view: duodenal bulb

The prevalence of coeliac disease is estimated to be one in 100 in the general population, although only 10-15 per cent of these are thought to have been clinically diagnosed. While many of the remainder will feel well, a significant minority will have chronic health problems such as GI symptoms, the effects of anaemia and lethargy. These symptoms may result in recurrent consultations with GPs and extensive investigations without a concluding diagnosis.

Coeliac disease can be effectively treated simply by a switch to a gluten-free diet so it is important for GPs to identify people with undiagnosed disease to improve their health.

Serological testing
NICE recommends that GPs offer serological testing for children and adults with any of the following signs and symptoms:

  • Chronic or intermittent diarrhoea
  • Failure to thrive or faltering growth in children
  • Persistent or unexplained GI symptoms, including nausea and vomiting
  • Prolonged fatigue ('tired all the time')
  • Recurrent abdominal pain, cramping or distension
  • Sudden or unexpected weight loss
  • Unexplained iron-deficiency anaemia, or other unspecified anaemia.

Furthermore, NICE recommends GPs offer serological testing to children and adults with any of the following conditions:

  • Autoimmune thyroid disease
  • Dermatitis herpetiformis
  • Irritable bowel syndrome
  • Type-1 diabetes
  • First-degree relatives (parents, siblings or children) with coeliac disease.

NICE also recommends that GPs consider serological testing for coeliac disease for adults and children with a variety of other symptoms and conditions.1

NICE suggests GPs advise patients that serological tests are only accurate if the patient continues to eat a diet containing gluten during investigations. It is suggested that some gluten should be eaten more than once a day for a minimum of six weeks before testing.

Patients also need to be advised that serological tests do not diagnose coeliac disease, but only indicate whether further testing is required.

NICE has suggested that laboratories undertaking serological tests should:

  • Use IgA tissue transglutaminase (tTGA) as the first-choice test
  • Use IgA endomysial antibodies (EMA) testing if the result of the tTGA test is equivocal
  • Check for IgA deficiency if the serology is negative
  • Use IgG tTGA and/or IgG EMA serological tests for people with confirmed IgA deficiency
  • Communicate the results clearly in terms of values, interpretation and recommended action.

Once implemented by local laboratories, the above suggestions should give GPs clear and useful laboratory results that will guide them on the clinical actions required.

Test results
NICE advises that GPs should refer to a GI specialist any patient with positive serological tests (either tissue tTGA or EMA). If serological tests are negative but coeliac disease is still clinically suspected, GPs should refer to a GI specialist.

Associated risks
People with coeliac disease, particularly those who have yet to be diagnosed and those who do not adhere to a gluten-free diet, have a higher risk of known complications such as malignancy, osteoporosis and fertility problems.

Studies suggest people with coeliac disease have a modestly increased risk of malignancy, particularly related to lymphoma. However, this risk appears to fall after diagnosis in those patients who keep to a gluten-free diet.2,3

At diagnosis, 40 per cent of patients have been found to have reduced bone mineral density. This translates in to a modestly increased fracture risk.4 For this reason, current guidelines suggest patients with coeliac disease should be considered for dual X-ray absorptionometry at diagnosis and then appropriate specified intervals at follow-up. Bone mineral density in people with coeliac disease has been shown to improve following management with a gluten-free diet.5

Subfertility, and increased risk of miscarriage and intrauterine growth retardation have been attributed to undiagnosed coeliac disease. These risks are thought to be reduced by keeping to a gluten-free diet.

Although being given a diagnosis of coeliac disease and starting a gluten-free diet may have an adverse psychological impact and be socially restrictive, most symptomatic patients have been shown to have an improved quality of life once diagnosis is made and they start on a gluten-free diet.

Management
The gluten-free diet is the cornerstone of the management of coeliac disease. Most patients struggle with accepting the diagnosis and the dietary requirement it brings. For that reason, education and support from a dietitian and the GP is vital.

The dietitian is a key source of information of managing the gluten-free diet in the variety of social situations patients face (home, work, school, restaurants and holidays).

The dietitian is able to advise patients so that they maintain adequate nutritional intake of calcium, iron, fibre, folate and vitamin B12.

Furthermore, some patients eating a gluten-free diet can experience significant weight gain, and will therefore need advice on appropriate macronutrient and calorific intake.

Patient compliance with the gluten-free diet may be assessed with repeat duodenal biopsy to ensure the villous atrophy has resolved, repeat antibody testing to ensure that antibody levels have become negative, dietary history and a resolution of symptoms.

Guidelines advise that patients should have an annual follow-up with a clinician to help compliance, because evidence suggests that regular follow-up with a clinician improves dietary compliance.6

Annual checks of serology and blood count may identify major dietary lapses.

Recent studies suggest patients on an established gluten-free diet may be able to introduce modest amounts of oats (<50g a day) under clinical supervision without adverse effects.7

If symptoms continue despite a gluten-free diet, careful dietary evaluation is required.

Persisting symptoms, or new alarm symptoms such as weight loss, rectal bleeding or change of bowel habit, may require referral to a gastroenterologist for further assessment.

Prevention
Studies suggest that breastfeeding has a protective effect and reduces the risk of the child developing coeliac disease in later life. For this reason, GPs should encourage breastfeeding, particularly in those parents who are coeliac themselves, for at least the first six months of life.

Current DoH guidelines recommend that foods containing gluten should be gradually introduced into infant diets only after six months of age, as earlier introduction is thought to increase the risk of developing coeliac disease.

  • Dr Sohail Butt is a GP in Ashford, Middlesex.

References

1. NICE Clinical Guideline 86. Coeliac disease: recognition and assessment of coeliac disease. London: NICE, May 2009.

2. Holmes G K, Prior P, Lane M R, Pope D, Allan R N. Malignancy in coeliac disease - effect of a gluten free diet. Gut 1989; 30: 333-8.

3. West J, Logan R F, Smith C J, Hubbard R B, Card T R. Malignancy and mortality in people with coeliac disease: population based cohort study. BMJ 2004; 329: 716-9.

4. Walters J R. Analysis of the absolute risks in coeliac disease indicates the importance of the prevention of osteoporosis. Gut 2007; 56: 310.

5. McFarlane X A, Bhalla A K, Reeves D E, Morgan L M, Robertson D A. Osteoporosis in treated adult coeliac disease. Gut 1995; 36(5): 710-4.

6. Bardella M T, Molteni N, Prampolini L et al. Need for follow up in coeliac disease. Arch Dis Child 1994; 70: 211-3.

7. Garsed K, Scott-Brian B. Can oats be taken in a gluten-free diet? A systematic review. Scand J Gastroenterol 2007; 42(2): 171-8.

Further Reading

Jones R, Sleet S. Coeliac disease. BMJ 2009; 338: a3058.

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