Cystic Fibrosis-Related Diabetes

What is CFRD?

In people with cystic fibrosis, the thick, sticky mucus 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 keep you healthy and maintain good nutrition. According to the 2021 CF Foundation Patient Registry, about 19% of people with CF have cystic fibrosis-related diabetes (CFRD). CFRD shares some features with both type 1 and type 2 diabetes. 

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

The goal for managing CFRD is to keep your blood sugar (glucose) at normal or near-normal levels, and to keep up with normal nutrition. Your CF and diabetes care teams can help you successfully manage CFRD. 

How Do I Know if I Have CFRD?

What Are the Symptoms of CFRD?

People with CFRD may not notice any symptoms. Some diabetes symptoms are like 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.

Testing for CFRD

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 eight-hour fast. If you are diagnosed with CFRD, you will 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.
Managing CFRD

The goal for managing CFRD is to keep your blood sugar (glucose) at normal or near-normal levels, and to maintain normal nutrition including muscle mass. 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:

  • Insulin.
  • Monitoring your blood sugar levels.
  • Eating your usual high-calorie diet.
  • Staying active.
”Many people with CFRD are unsure about what to eat to manage their blood sugar levels. Fortunately, certain meal planning techniques can help.” — Gretchen Garlow, MS, RD, LDN, a CF dietitian, from the CF Community Blog

Taking Insulin

There are many types of insulin. They are grouped by how fast they work and how long they last in your body. You inject insulin into your body and it helps your cells absorb the energy (calories) from the food you eat. Calories in food come from carbohydrates, protein, and fat. Insulin helps your cells absorb these three nutrients so that you can achieve and maintain a healthy  weight and good nutritional status.

What You Eat Is Important

Since foods with carbohydrates turn into blood glucose when you digest them, you may need to count the carbohydrates in your foods so you can know how much insulin to take. Many people with CFRD will 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. On the other hand, many people with CF find that taking highly effective CFTR modulators makes it easier for them to gain weight. Your diabetes care team can help you determine the eating plan that is right for you as well as the amount of insulin you need for your carbohydrates.

Physical activity like exercise can help you improve your body's response to insulin. People with CFRD are encouraged to do at least 150 minutes of some type of moderate aerobic exercise every week. Aerobic exercise includes that require you to breathe in oxygen, like jogging or playing sports. Muscles use sugar for energy. So checking your blood sugar levels will allow you to remain active since exercise can cause the levels to drop.

If you have CFRD, be sure to check your blood sugar before and after exercise.” — Lee Degiorgio, an adult with CF, from the CF Community Blog

The Emotional Impact of Finding Out You Have CFRD

A CFRD diagnosis can have negative emotional effects. Many people with CF express frustration at having another long-term condition that takes time and effort to manage.  

”CF already consumes so much of our daily lives. Do we really need to add blood sugar management on top of it all?" — Megan LePore, an adult with CF, from the CF Community Blog


Coping with a new diagnosis like this can be difficult, but discussing it with your CF or diabetes care team may help. You may also find help through CF Peer Connect. CF Peer Connect is a one-to-one peer support program for people with cystic fibrosis and their family members age 16 and older. You can talk with and learn from someone who has gone through similar experiences.

Help From Your Care Team

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 certified diabetes educators. Working with you, this team will design a plan to help you manage your diabetes while also maintaining your health with CF.

Download the manual, "Managing Cystic Fibrosis-Related Diabetes."

What Research Is Being Done?

The CF Foundation has funded researchers who are investigating the effect that the cystic fibrosis transmembrane conductance regulator (CFTR) protein has on the development of CFRD to find ways to treat it.

In this video, a panel of research experts and community members discuss several research studies aimed at improving CFRD diagnosis and treatment.
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