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CF-related diabetes

Cystic fibrosis (CF) can cause a range of problems with the digestive system, requiring special dietary considerations, and medications that must be taken with every meal, even including insulin.


What is cystic fibrosis-related diabetes?

In most people with cystic fibrosis (CF), the pancreas doesn’t work properly, also known as ‘pancreatic insufficiency’, which causes two important medical issues.

Sketch of some food items for the Cystic Fibrosis TrustFirst, the small tubes that transport enzymes out of the pancreas become blocked with mucus. This prevents the enzymes from reaching the digestive system and breaking down foods such as carbohydrates, proteins and fats so that they can be absorbed in the gut. This is why most people with cystic fibrosis have to take pancreatic enzyme replacement therapy (Creon®) with food and snacks containing fat. Find out more about how CF affects the digestive system.

Second, inflammation and scarring of the pancreas can prevent the effective production of insulin, resulting in CF-related diabetes (CFRD).

How common is cystic fibrosis-related diabetes?

Cystic fibrosis-related diabetes is common in adults and adolescents with cystic fibrosis. Recent data from the UK CF Registry indicates that more than one-third of adults with CF are being treated for CFRD; for children the prevalence of CFRD almost 30%.

How is cystic fibrosis-related diabetes different from diabetes?

CFRD is distinct and different from type 1 and type 2 diabetes, but has features of both.

People with cystic fibrosis may be more at risk of episodes of CFRD or high blood glucose levels due to infection or drugs such as oral steroids or immunosuppressants. In some cases, this may be temporary and may resolve itself when the infection is treated, or when the steroids are reduced or stopped.

It is possible for someone with CF to get type 1 or type 2 diabetes mellitus.

What are the symptoms of cystic fibrosis-related diabetes?

With routine screening for diabetes, most cases of CFRD are picked up before any symptoms occur. However, it’s important to know and recognise the symptoms of CFRD. They can include weight loss, increased thirst and the need to pass urine more frequently, although some people will not experience any symptoms.

If untreated, high blood glucose levels can cause long term complications such as poor body weight, recurrent chest infections, reduced lung function, kidney damage, nerve damage and problems with eyesight.

How is cystic fibrosis-related diabetes diagnosed?

There are different methods for screening for CFRD. These include:

  • Serial blood glucose monitoring or continuous glucose monitoring (CGM)
  • The haemoglobin A1c blood test (HbA1c)

Diabetes may also be suspected if a random or fasting glucose level is abnormally high, but these measurements are less accurate for the early diagnosis of CFRD.

How is cystic fibrosis-related diabetes treated?

Sketch of a needle for the Cystic Fibrosis TrustAlthough diabetes can’t be cured, it can be treated and managed very successfully. While some people with diabetes can control their blood sugar levels by taking tablets, most people with CFRD are best treated with insulin. Insulin can’t be consumed orally because it is destroyed by acid in the stomach, so it is usually given as an injection.

If you have CFRD, you will probably be advised by medical experts to have a diet that consists of a lot of high-energy foods. They are also likely to recommend that your insulin dose is adjusted to your individual requirements.

Download our CFRD factsheet to find out more about how cystic fibrosis-related diabetes is treated.

Find out more

Our CFRD factsheet covers everything from how you might feel after you are diagnosed with cystic fibrosis-related diabetes to guidelines about treating the condition and how to adapt your diet. You can also find out more about our Strategic Research Centre investigating CFRD.

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