Cystic fibrosis-related diabetes (CFRD) is a unique type of diabetes that is common in people with cystic fibrosis. With early diagnosis and proper treatment, CFRD can be managed successfully.

Causes of CFRD

There are two types of diabetes in people without cystic fibrosis: type 1 and type 2. Type 1 diabetes is an autoimmune disease that occurs when the body’s immune system attacks and destroys the cells in the pancreas that make insulin (beta cells), which helps the body absorb and use the energy from food. Type 1 diabetes is most diagnosed in childhood and requires you to take insulin to stay alive.

Type 2 diabetes, which occurs more often in adults who are overweight or obese, is caused by the lack of a normal response to insulin in addition to the pancreas not making enough insulin.

Cystic fibrosis-related diabetes (CFRD) shares some features with both type 1 and type 2 diabetes. In people with cystic fibrosis, the thick, sticky mucus that is characteristic of the disease causes scarring of the pancreas. This scarring prevents the pancreas from producing normal amounts of insulin; so, like people with type 1 diabetes, they become insulin deficient. Their pancreas still makes some insulin, but not enough to stay healthy and maintain good nutrition.

Additionally, people with CFRD may not respond to insulin in the right way like people with type 2 diabetes do, especially when sick, taking steroid medication, or pregnant. This is referred to as being “insulin resistant.”

Symptoms, screening, and diagnosis

People with CFRD may not experience any symptoms. Some diabetes symptoms are like other cystic fibrosis symptoms and therefore diabetes may go undetected for some time. Many people with CFRD do not know they have CFRD until they are tested for diabetes.

Some common symptoms, like increased thirst and urination, are caused by high blood sugar levels, known as hyperglycaemia. Other symptoms of CFRD are excessive fatigue, weight loss, and unexplained decline in lung function.

It is recommended that people with cystic fibrosis ages 10 and older be tested every year for CFRD with an oral glucose tolerance test (OGTT). The OGTT is the best way to diagnose CFRD and is usually done in the morning after an eight-hour fast. When cystic fibrosis people are diagnosed with CFRD, they will receive proper treatment to feel better, gain weight, and improve their lung function.

Treating CFRD

The goal for treating CFRD is to keep blood sugar (glucose) at normal or near-normal levels. Doing so will help weight gain, maintain muscle mass, improve mood, and energy levels. Maintaining normal glucose levels also lowers the risk of problems caused by diabetes.

CFRD can be well managed with insulin, along with monitoring blood sugar levels, eating the recommended cystic fibrosis high-calorie diet, and staying active.

There are many types of insulin, which are grouped by how fast they work and how long they last in the body. Insulin is injected into the body and helps body cells absorb the energy (calories) from food. Calories in food come from carbohydrates, protein, and fat. Insulin helps the body cells absorb these three nutrients so that a healthy body weight and good nutritional status can be maintained.

People with CFRD still need to eat the same high-calorie, high-protein, high-fat, and high-salt diet to help achieve and maintain a healthy body weight. Since foods with carbohydrates turn into blood glucose when eaten, people with CFRD need to count the carbohydrates in the foods they eat so they can give themselves the right amount of insulin.

Physical activity like exercise is good for lung function and can also improve a person’s response to insulin. People with CFRD are encouraged to do at least 150 minutes of some type of moderate aerobic exercise — activities that require you to breathe in oxygen, like jogging or playing sports — every week. Monitoring blood sugar levels allows people with CFRD to remain active since exercise may cause the levels to drop when muscles use the sugar for energy.