Cystic fibrosis-related diabetes (CFRD) is a complication of cystic fibrosis (CF), a lung disease. CFRD adds to the risk and seriousness of health problems in those affected by CF. This form of diabetes happens due to problems with how sugar is processed in the body, mainly due to lack of insulin and moving in and out phases of insulin resistance. It’s important to spot the early signs of sugar processing problems in people with CF for timely CFRD diagnosis. Detecting and treating CFRD earlier helps slow down the worsening of lung conditions and boosts growth. This summary aims to give you a basic understanding of CFRD.

The exact cause of diabetes related to cystic fibrosis isn’t fully known. What we currently understand is that it’s a complex condition likely caused by a combination of problems in the beta cells (cells that produce insulin in the pancreas) and a decrease in the mass and number of islet cells (clusters of cells in the pancreas that help regulate blood sugar).

Cystic fibrosis-related diabetes is a widespread condition among people with cystic fibrosis. The likelihood of having it increases as you get older. It affects 2% of children, 19% of teenagers, and up to 50% of adults aged 30 and above. However, the reported rate might be lower at healthcare centers that don’t regularly conduct oral glucose tolerance tests.

Cystic fibrosis-related diabetes is common among those with cystic fibrosis.
The risk of developing it increases with age.
It is found in 2% of children.
19% of adolescents have it.
Up to 50% of those 30 years and older have it.
Some health centers might report lower rates if they don’t routinely perform oral glucose tolerance tests.

People diagnosed with Cystic Fibrosis-Related Diabetes (CFRD) usually show no clear symptoms at first. Unlike with other forms of diabetes, increased thirst and frequent urination are less common in CFRD. Often, the first sign of CFRD may be difficulty in maintaining or gaining weight despite eating enough. In children with cystic fibrosis, growth slowdown and weight loss can occur several years before CFRD diagnosis. It’s also possible that there might be no noticeable decrease in BMI due to both height and weight decreasing together. Therefore, keeping track of growth and weight changes are very important in children suffering from cystic fibrosis.

Cystic Fibrosis-Related Diabetes (CFRD) may not always show the typical signs of diabetes. This is why regular testing for CFRD is crucial for people with cystic fibrosis. Medical organisations like the Cystic Fibrosis Foundation and the American Diabetes Association suggest a specific test. This test involves consuming a 75-gram oral glucose solution (or 1.75 gm glucose/kg for individuals under 42 kg body weight) and then checking the glucose levels in the blood after 2 hours. This is currently the most reliable screening method for CFRD. It’s recommended that all people with cystic fibrosis start getting annual tests for CFRD by age ten.

Other testing methods like checking glucose levels in urine, random blood glucose level checks, testing for a blood component known as fructosamine, and checking hemoglobin A1c levels aren’t recommended. This is because these tests aren’t sensitive enough to accurately diagnose CFRD.

The standard criteria, as provided by the American Diabetes Association, are used to diagnose CFRD. If the 2-hour glucose test shows a blood glucose level over 200 mg/dL, or a fasting blood glucose level is more than 126 mg/dL, or hemoglobin A1c is over 6.5%, it can indicate CFRD. Additionally, a random glucose level over 200 mg/dL in conjunction with clinical symptoms can point towards CFRD. During periods of severe illness, CFRD can be confirmed if the 2-hour after eating glucose test or a fasting glucose level is high on a consistent basis for more than 48 hours.

Continuous glucose monitoring (CGM) is becoming more popular among these individuals. Currently, studies are being conducted to create standard testing procedures using this method.

Insulin is the go-to treatment for people with diabetes related to cystic fibrosis (CFRD). It helps control blood sugar levels, promotes weight gain, and improves lung function. People with CFRD should continue to eat as they usually would and start taking insulin to help manage their blood sugar levels.

If they don’t have high blood sugar levels when they are not eating (fasting), they can manage their CFRD by taking fast-acting insulin with meals. How much insulin they need to take before meals is based on how much carbohydrate they eat.

If CFRD individuals have high blood sugar levels while fasting, they should start using a combination of long-lasting (basal) insulin and fast-acting insulin at meal times. If they’re getting fed overnight through a tube in their stomach, a mix of regular and NPH insulin could help manage the ongoing carbohydrate delivery.

People with CFRD can sometimes become resistant to insulin and need more insulin during times of significant sickness due to inflammation. These increased insulin needs can drop quickly once the sickness gets better. Blood sugar levels in people with CFRD need to be carefully watched during these times. At the moment, the suggested blood sugar target before eating is between 70 to 130 mg/dL, and below 180 mg/dL three hours after meals.

Currently, there isn’t enough evidence to advise using non-insulin injections or oral glucose-lowering drugs for CFRD. These medications should only be given to people within research studies.

Cystic fibrosis-related diabetes (CFRD) shares similarities with both type 1 and type 2 diabetes, but it’s important to understand how it’s different for proper diagnosis and treatment. Unlike type 1 diabetes which sets in suddenly over weeks to months, CFRD develops slowly over years. People with CFRD still produce some insulin, unlike those with type 1 diabetes.

In type 1 diabetes, a condition called ketoacidosis, where the body starts breaking down fat because it can’t access sugar for energy, is common. But in CFRD, this rarely happens due to the body still being able to produce some insulin. Another key difference is that the damage to insulin-producing beta cells in CFRD isn’t linked to autoimmune disease, and people with CFRD usually don’t have autoimmune-related diabetes antibodies.

Next, let’s look at how CFRD compares to type 2 diabetes. In CFRD, insulin resistance, a condition where the body doesn’t respond well to insulin, isn’t permanent. It’s usually temporary and results from being ill or from steroid treatments. On the other hand, in type 2 diabetes, insulin resistance is long-term and is there even when the individual is in good health.

Cystic fibrosis-related diabetes is a condition that lasts a lifetime and currently has no definitive cure. However, it can be treated effectively with insulin therapy. People with cystic fibrosis who also have this form of diabetes are at a higher risk of dying at a younger age compared to those who don’t.

Regular diabetes screening and the early use of insulin therapy have significantly lowered the risk of death from cystic fibrosis and this related diabetes. The most common cause of death from this condition is due to pulmonary, or lung, failure. While it’s not entirely clear why this form of diabetes accelerates lung decline, long-term high blood sugar levels are known to have harmful effects on lung function. They hinder the body’s ability to get rid of bacteria and increase oxidative stress in the lungs. This results in a decrease in lung function and ultimately, lung failure.

Microvascular complications are common in people with Cystic Fibrosis-Related Diabetes (CFRD). A research study that analyzed 285 individuals with CFRD who had high blood sugar levels in the morning, found out that numerous small vessel complications were quite prevalent. These complications occur less frequently in patients who have had CFRD with high fasting blood sugar for under 10 years. Additionally, there are no cases of microvascular complications in individuals with CFRD who do not have high fasting blood sugar levels. Interestingly, large blood vessel complications, while common in other forms of diabetes, are not often seen in CFRD.

Common Complications Found in CFRD:

Neuropathy in 55% of subjects.
Gastropathy in 50% of subjects.
Retinopathy in 16% of subjects.
Microalbuminuria in 14% of subjects.

So far, no specific treatment has been found to effectively prevent the progression to Cystic Fibrosis-related Diabetes (CFRD) in people who have Cystic Fibrosis. However, regular yearly check-ups can help doctors to catch problems with blood sugar control before full-blown diabetes develops. These check-ups provide an opportunity for the individual, and their family, to understand more about diabetes before the need for insulin treatment arises.

After a person has been diagnosed with CFRD, it’s important for them to see a specialist, known as an endocrinologist, who can start them on insulin therapy. Patients, or their families, may need to measure their blood sugar levels themselves, usually at least three times a day. Depending on the patients’ unique blood sugar tendencies, they may need to inject insulin as little as once daily, or as much as four to six times per day.

Treating CFRD effectively is a complex process and requires proper education and active involvement from the patient and their parents. This understanding and engagement are crucial for the best care and disease management.