Assessing response to a gluten-free diet
The gold standard to assess the response to a gluten-free diet is normalisation of small bowel villi on biopsy. It is important to inform patients that the rate of response varies. Some patients report an improvement in symptoms such as diarrhoea within weeks; however, other symptoms such as fatigue and bloating may take months to improve.
Antibody testing may be repeated 6 to 12 months after a gluten-free diet has been introduced. It can be helpful for assessing response and adherence to a gluten-free diet, but it can take longer than 12 months for antibody levels to return to normal. If antibody levels are not improving after 9 to 12 months, refer the patient to an accredited practising dietitian. Some patients have a poor initial response to a gluten-free diet. The most common cause is inadvertent gluten ingestion, so the patient’s diet should be thoroughly reviewed by the dietitian.
Intestinal healing can take up to 2 years, so repeat duodenal biopsy should not be performed until the patient has been following a gluten-free diet for at least 12 months.
Patients who are not responding to a gluten-free diet should be screened for associated diseases, particularly thyroid disease, microscopic colitis and diabetes. If a patient has been assessed by a dietitian and there is still no response to the gluten-free diet after 12 months, refer to a gastroenterologist for further investigation and consideration of immunosuppressive therapy.
There is an association between coeliac disease and microscopic colitis. Patients who continue to have diarrhoea despite adhering to a gluten-free diet may need referral for further investigation (including colonoscopy).