Testing For CFRD

If you have been diagnosed with CF-related diabetes, this will likely affect your day-to-day living as you will need to be aware of the foods that you eat, monitor your sugars, and take insulin to help manage your blood sugars. Read more about why people with CF can develop CFRD by checking out our endocrine pancreatic function section.

We believe that aggressive and early replacement of insulin can improve lung function, increase muscle mass, stop weight loss, and help people with CF related diabetes to live longer, healthier lives. Once a year you will be tested for diabetes with a screening blood test (HbA1C) or an oral glucose tolerance test (OGTT).

As most people know, the oral glucose tolerance test (OGTT) is a regular part of your yearly tests. To have an OGTT you must be fasting. This means nothing to eat or drink other than water for 8 hours before the test. The test takes 2 hours. Your blood sugar is measured and then you are asked to drink a sugar-drink. Your blood sugar is then tested again 2 hours after the drink. Two hours is the normal amount of time the body should take to absorb the sugar into your cells from your bloodstream. In a healthy body, insulin is released from the pancreas in response to the high sugar load, which triggers the absorption of sugar out of the blood and into the cells.

A high level of sugar in the blood tells us that the cells in the body have not absorbed enough of the sugar and there is impaired glucose tolerance, or diabetes. It is best to have the test done at a time when you are not sick, since illness can affect your body’s ability to efficiently use insulin. If you are booked for an OGTT and are unwell, please call the clinic ahead of time so the test can be re-scheduled. Also, if you have symptoms of diabetes, are pregnant, or are on oral steroids (prednisone) we may do the test more often because these situations place you at higher risk for developing diabetes.

Within this section, you will learn the various ways that you can monitor your sugars, what is an optimal blood sugar range, how to carbohydrate count, the impact of CFRD on nutrition, pregnancy, and post-transplant among other things.

Monitoring Blood Sugars

These devices provide excellent medical and lifestyle benefits. People can now see in real-time the effects of food and exercise on your blood glucose levels, and can catch cases of high and low blood sugars as they happen, avoiding the potentially dangerous consequences. CGM and FGMs can essentially eliminate the need for those regular fingerstick tests, the long-standing only way to check blood sugar levels. Additionally, most CGMs can send alerts telling you when your blood sugar levels are rising too high or dropping too low. You can also set the alert parameters, customize how you are notified, and share data with both family members and your diabetes care team.

If you are interested in learning more about these devices, please contact your CF Diabetes Educators.

It is important to monitor your blood sugars regularly. High sugars can promote infection. Our goal is to help you achieve optimal blood sugar control. Follow the guidelines listed below to keep your diabetes under control.

Blood sugar targets are as follows:
Fasting: less than 7mmol
Pre-meals between: 5–7 mmol/L
2 hours post-meals: 5–10 mmol/L ( if HbA1C≤ 7%)
2 hours post-meals: 5–8 mmol/L ( if HbA1C> 7%)
Glycosylated hemoglobin (HbA1C): less than 7%

Goals of therapy are to:
-Avoid severe hypoglycaemia (low blood sugars)
-Maintain optimal nutrition
-Maximize psychological well being
-Prevent long term complications of diabetes

Click here to download a blood glucose monitoring record. You can either print this off and bring it with you to your next clinic visit or you can keep track of your sugars on your computer and email the completed sheet to our CF Diabetes Educators Sandee Westell RN, Lisa Mannik RD or Ronalee Robert RD.

A continuous glucose monitoring system, or CGM, is a compact medical system that monitors your blood sugar levels in more or less real time. To use a CGM, you insert a small sensor onto your abdomen that includes a tiny cannula that penetrates the skin. An adhesive patch holds the sensor in place, allowing it to take glucose readings in interstitial fluid (the fluid that surrounds cells in the body) throughout the day and night. Generally, the sensors have to be replaced every 10 to 14 days. A small, reusable transmitter connected to the sensor allows the system to send real-time readings wirelessly to a monitor device that displays your blood glucose data. Some systems come with a dedicated monitor, and many now display the information via a smartphone app, so you don’t need to carry an extra device around with you. Unlike a traditional fingerstick blood glucose meter, which provides just a single glucose reading, CGM systems provide continuous, dynamic glucose information every five minutes. That equates to roughly 288 readings in a day. Dexcom and Medtronic are two options available in Canada now.

Flash Glucose Monitoring (FGM) is a method of glucose testing that is seen as a hybrid between meters and CGMs. The FreeStyle Libre is currently the only flash glucose monitoring product available. In Flash Glucose Monitoring, a sensor is inserted on the upper arm and a separate touchscreen reader device or smart phone with the downloaded app is swiped close to the sensor. The sensor transmits both an instantaneous glucose level and eight-hour trend graph to the reader. This allows people to get individual blood sugar readings and trend information.

Carbohydrate Counting & CFRD

Carbohydrate counting is a meal planning method for people with diabetes.The amount of carbohydrate in foods is one of the factors that affect blood sugar levels (stress, activity, alcohol and illness do also). Counting carbohydrates allows you to add flexibility to your food choices without compromising your blood sugar control. At first, it takes a little work (record keeping) but many people find the results worth the effort.

Experience helping others with diabetes has taught us a few tricks that might help you. It is very important that you DO NOT cut down on the amount of food that you eat in order to try and control your blood sugar levels! You still need to follow your usual high-calorie, high fat diet (with NO restrictions on carbohydrates or sugars) to help you achieve and maintain a healthy body weight. Monitoring your blood sugars and taking the correct amount of insulin will help you to maintain your weight and stay healthy!

More information on how to carbohydrate count can be found here.

Insulin Therapy for CFRD

When someone is diagnosed with CF related diabetes, we will ask you to monitor your blood sugars for two weeks consecutively (see blood sugar monitoring in an above section), and based on your blood sugar results you CF team may start you on insulin therapy. There are many different types of insulin therapy depending on your unique blood sugar pattern. Your healthcare team will work with you to determine which insulin type is best for you. Insulin is given via sub-cutaneous injection. Usually people are started on multiple injections per day but in time, it may be possible to switch to an insulin pump.

An insulin pump is a small, computerized device worn outside the body that delivers insulin to your body through a tiny plastic tube. The pump is about the size of a cell phone and can be clipped onto your pants and hidden underneath your clothes. Insulin pumps deliver one type of insulin (rapid) in a way that is closer to a healthy pancreas.

More Flexibility
You can program the pump to give more or less basal (between meal) insulin at different times of the day. For example you could set the basal rate lower during exercise or higher when you’re taking medications such as prednisone.

Fewer Needles
Only one “needle stick” every 3 days when you change the infusion site is required, instead of a needle every time you take insulin. Also, you can eat a meal or snack whenever you want, without having to worry about giving yourself another needle.

Better Coverage
The pump allows a bolus (meal-time insulin) to be given over several hours, instead of all at once. This can be very helpful for those who snack over a period of several hours or for high fat meals that take a long time to digest.

Calculation Help
The pump can keep track of your insulin to carbohydrate ratio for each meal and your correction factor. If you enter your blood sugar result and the amount of carbohydrate you’re about to eat, it will give you an insulin dose suggestion.

According to research in patients with CFRD, the pump can help you to achieve better blood sugar control, a better weight and more muscle mass. Also, people using the pump had less low blood sugars.

If the infusion set is inserted properly, you shouldn’t feel it at all.

The needle does not remain under your skin. The needle is only used to insert the tiny plastic tube under your skin and then it is disposed of.

The pump is not for everyone. Ask yourself the following questions:

  1. Can you carbohydrate count or can you learn to?
  2. Do you check your blood sugar at least four times a day?
  3. Would you be comfortable wearing the insulin pump (which is attached to your clothing) most of the day?

If you answered yes to these questions, an insulin pump may be something to consider to manage your blood sugars. Talk to your CF team to get more information on how an insulin pump may help you.

  1. The first step is to see a diabetes doctor (endocrinologist) to assess whether you are a good candidate for a pump. They may want to see you a few times to make sure that you check your blood sugars often and know how to carbohydrate count.
  2. Then, the endocrinologist will refer you to a diabetes education centre. The St Michael’s Hospital diabetes education centre at 61 Queen St. E on the 7th floor. They will help you to apply for ADP funding from the government for the insulin pump and supplies.
  3. Once you have been approved, the pump will be shipped to you. You will then make an appointment at the diabetes education centre to learn how to use your pump. You will get lots of practice before you start receiving your insulin from the pump.
  4. Once you are up and running with your pump, you will be followed in the CF clinic for your blood sugar control as usual.

Nutrition & CFRD

To ensure good health, it is important to maintain a healthy body weight. With other types of diabetes, people are often told to eat a low-fat, low-salt and sometimes low-calorie diet. People living with CF-related diabetes still need the normal high-calorie, high-protein, high-fat, high-salt “CF diet” to help you achieve and maintain a healthy weight. Keeping your blood sugar at near-normal levels will help to maintain your weight and ensure good health.

The main change in terms of your diet when you have CF-related diabetes is learning how to measure or identify the foods that affect your blood sugars the most and adjust your insulin accordingly. It is still important to eat a well-balanced meal from all the food groups in addition to consuming extra fats and sweets for more calories.

Carbohydrates have the most effect on blood sugar levels as they are broken down into sugars that are absorbed into the blood. Protein and fats do not raise blood sugar levels but they are important as they can slow down the absorption of sugars which can help to stabilize sugar levels in the blood. The main way to control your blood sugar is to control the amount of carbohydrates in your meals/snacks. You should not avoid carbohydrates as they are an important component of weight gain. This means that foods that are sweet, including desserts, are all part of a balanced diet, even when you have diabetes. This is very different from people who have diabetes that is not related to CF. To learn how to manage your carbohydrates with CF-related diabetes your CF dietitian can help develop a plan that works best for your lifestyle.

See the Carbohydrate Counting content above or download our Insulin and Snacking document for additional information.

Pregnancy & CFRD

If you are considering pregnancy, you will need to do an oral glucose tolerance test (OGTT). Diabetes during pregnancy is more common in women with CF. The OGTT will need to be repeated once pregnancy is confirmed and then again in the 2nd and 3rd trimesters. Untreated diabetes may lead to a loss in energy, weight, and increase your risk for illnesses. It can also have harmful effects on your baby. If you have diabetes, monitoring your blood sugar is necessary so that you can achieve optimal sugar control prior to pregnancy. The target blood sugar values are different in pregnancy so make sure you review this with your CF team. After your delivery, your sugars should be re-checked within 6-8 weeks post-partum to ensure that they have returned to normal.

Lung Transplantation and CFRD

The chance of developing diabetes after transplant is high for two reasons: people with CF have a higher chance of developing diabetes and the steroids prescribed after transplant can cause high blood sugars. If you already have diabetes, continue to monitor your blood sugars and adjust your insulin dose with the help of your medical team. Be sure to check your blood sugar level approximately 6-8 hours after you take your prednisone dose. If you did not have diabetes before transplant, your blood sugar level will be checked as part of your transplant bloodwork. It is important for you to self-monitor your blood sugar levels approximately two hours after your meals. Also, watch for the following symptoms and let your transplant team know if you experience them:

  • Unexplained weight loss
  • Feeling more tired
  • Feeling very thirsty
  • Change in appetite
  • Urinating more often
  • Blurry vision
  • Skin infections
  • Wounds or sores that do not heal easily

If you want more information on this topic speak with our dietitians or your medical team.

Impaired Glucose Tolerance

People with CF and IGT often (although not always) still need a high-calorie diet to help maintain a healthy body weight. Foods such as sugary drinks (pop, juice, and sweetened coffee beverages), syrups, honey, and candy can cause high blood sugars. They also have low nutritional value. If you choose to have these foods sometimes, eat them in small quantities and try to have them with a meal so that the sugar is absorbed more slowly.  It is important to eat regular meals and snacks throughout the day to have a constant fuel source for your body. Monitoring your blood sugars to make sure they are near normal levels will help you to maintain your weight and stay healthy.

About 40-50% of the adults and up to 35% of children and adolescents 10-18 years of age with CF have impaired glucose tolerance at some point which requires them to check their blood sugars for a period of time. It is possible that with time, someone who has IGT will develop diabetes in the future. It is also possible you will develop IGT for a short period of time (i.e. when you are sick) and then have normal blood sugar readings again.

Yes. We will teach you how to use a blood glucose monitor to check your sugar levels at home. It is important to check that your blood sugar levels are normal because significant weight loss and a decrease in lung function have been shown to begin a few years before diabetes has been diagnosed. By monitoring your blood sugar levels regularly, we can diagnose and treat diabetes early on to prevent complications such as weight loss or decreased lung function.

A member of the CF team will teach you how to check your blood sugars at home by using a blood sugar monitor. As well, we will work with you to set-up a schedule so you will know when to regularly check your blood sugars during the day. It is important that you record all of your blood sugar readings and bring these and your monitor with you to clinic so that you can discuss the results with your healthcare team.

No. You still need to follow your usual high-calorie, high-fat diet (with no restrictions on carbohydrates or sugars) to help you achieve and maintain a healthy body weight. It is important to eat regular meals and snacks throughout the day to have a constant fuel source for your body. Monitoring your blood sugars to make sure they are near normal levels will help you to maintain your weight and stay healthy.

It is important to be physically active. Regular exercise will help to move the sugar from your blood into your tissues and muscles to keep your blood sugar levels normal. Try to be active for at least 20-30 minutes three to five days a week.