Cystic Fibrosis-Related Diabetes

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

Causes of CFRD

There are two types of diabetes in the non-CF population. Type 1 diabetes (known as "insulin-dependent diabetes") is when the pancreas stops making insulin. Type 2 diabetes (known as "non-insulin dependent diabetes") is when the body lacks normal responses to insulin and the pancreas doesn't make enough insulin.

CFRD shares some features with both type 1 and type 2 diabetes. In people with CF, the thick sticky mucus that is characteristic of the disease causes scarring of the pancreas. This scarring prevents the pancreas from producing enough insulin, which is why people with CFRD experience a feature of type 1 diabetes when they become insulin deficient. Additionally, people with CFRD may not respond to insulin in the right way, a feature of type 2 diabetes. This is referred to as being insulin resistant.

Symptoms, Screening and Diagnosis

People with CFRD may not experience any symptoms. Some diabetes symptoms are similar to other CF symptoms you may already have. 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 hyperglycemia. Other symptoms of CFRD are excessive fatigue, weight loss and unexplained decline in lung function.

The CF care guidelines for CFRD recommend that people with CF 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 8-hour fast. If you are diagnosed with CFRD, you can receive proper treatment in order to feel better, gain weight and improve your lung function.

Listen to Andrea Kelly, M.D., talk about CFRD and what's changed since she's been in the field of CF.

Watch this webcast to learn more about CFRD diagnosis and screening.

Treating CFRD

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

CFRD can be well managed with medication while monitoring your blood sugar levels, eating a high-calorie diet and staying active.

Insulin is the medication used to treat CFRD. There are many types of insulin, which are grouped by how fast they work and by how long they last in the body. This is good news, because it means that there are many ways you can use insulin to control your blood sugar levels. Insulin is injected into the body so sugars and proteins can move from the blood into the body's cells. This process allows your body to create energy, build muscle and store fat.

Unlike people with type 1 or type 2 diabetes, people with CFRD need the same high-calorie CF diet they would normally eat in order to gain weight and build muscle. A healthy diet means eating a variety of foods that are high in protein, fat and salt. The only difference is that people with CFRD need to track or count the foods that affect their blood sugar levels the most.

Physical activity like exercise is good for lung function and can also improve your body's response to insulin. People with CFRD are encouraged to do 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 your blood sugar levels will allow you to remain active, since exercise may cause the levels to drop when muscles use the sugar for energy.

If you are diagnosed with CFRD, your CF care team may expand to include an endocrinologist (a doctor with special training in the treatment of diabetes) and a certified diabetes educator. Working with you, this team will design a treatment plan to help you manage your diabetes while also maintaining your health with CF.

Download the manual, "Managing Cystic Fibrosis Related Diabetes Manual, An Instruction Guide for Patients and Families."

The manual is also available in Spanish: "El Manejo de la Diabetes Relacionada con la Fibrosis Quística."